Blog & White

Seizième volume de Trolls de Troy Publié en 2012. Les trolls et Trollane arrivent à Eckmül tandis que les deux transporteurs essayent de vendre leur colis à Fuquatou. Sur ces entrefaits, tous les trolls du village, miniaturisés, arrivent en ville et sèment la pagaille. Ils se font enchanter par les sages qui leur ordonnent de retrouver le colis; seuls Waha et quelques autres échappent à l'enchantement. Waha utilise alors son pouvoir aléatoire et grâce au colis (une respiration de magohamoth) rend leur taille aux trolls qui avaient été enfermés dans une bouteille et jetés à la mer par Fuquatou; un plongeon dans l'eau rompt l'enchantement.

Dixième et dernier volume de De cape et de crocs, où l'on découvre que Séléné est en fait Roxanne, la princesse de la Lune qui avait disparu après sa naissance, et qu'elle est amoureuse du Maître d'armes. Don Lope se brouille avec Armand, et repart vers la Terre. Ils sont capturés par Mendoza, lui aussi en voyage vers la Terre. Pendant ce temps Armand repart vers la Terre avec les pirates et l'aide de Bombastus, et découvre ce qui arrivé à Don Lope. Armand arrive au secours de son ami, jettent Mendoza dans l'espace et finissent par arriver sur Terre. Ils découvrent qu'Hermine s'appelle en fait Yasmina et qu'elle est la fille perdue du Raïs Kader.

Vetinari forces Vimes to take a holiday. The latter leaves with his wife for the Ramkin estate in the countryside. Vimes soon suspects something is wrong, and is subsequently framed for the murder of the local blacksmith. Using his natural authority over the poor local constable, he forces the latter to help him investigate instead of arresting him. Goblins (considered as vermin) living in a nearby cave ask him to investigate the murder of a young goblin girl (the blood of whom was used for framing Vimes). A writer of children books, who had been raised by goblins before being raised by humans, has started to teach some goblins to read and write; one of them also plays wonderfuly well the harp. Vimes then discovers that a large number of goblins had been abducted three years back and sent to some unknown destination; one of the persons involved in that abduction is also co-responsible for framing Vimes and for smuggling tobbaco to Ankh-Morpork, and the tobacco smuggling is additionally a cover for smuggling illegal troll drugs. In the city, Fred Colon gets mysteriously sick because of a goblin artifact found in a cigar, which leads to the Watch finding out that goblins are used as slave labour in Howondaland, growing tobacco. Meanwhile in the countryside, Vimes learns that a new group of goblins is being shipped by boat over the river, and after a long chase in a stormy weather, he manages to save them. Having heard the goblin play the harp, Vimes' wife organizes a concert at the Ankh-Morpork opera house, making all influential persons on the Disc understand that goblins are sentient beings and must not be considered as vermin anymore.

“chocolate malts giving rise to hedgerow fruit, espresso and liquorice”

Quite strong, sweet, coffeeish and with a chocolate aftertaste. Contains barley malt, oats and wheat.

Black Isle Brewery, Black Isle, Highlands, Scotland. 7% alcohol.

“using Hersbrücker Lager hops…grapefruity tastes. Hops: Challenger, Styrian Goldings and Hallertau Hersbrüker.”

Quite flowery and a bit bitter. Quite nice, but not extraordinary. Contains barley and wheat.

Harviestoun Brewery, Alva, Clackmannanshire, Scotland. 4.8 % alcohol.

Five years after having left Metropolis, Superman is back. Clark Kent discovers that Lois has a boyfriend, and won the Pullizer price for an editorial on “Why the world does not need Superman”. At the same time, Lex Luthor manages to find Supermans' Fortress of Solitude and steals the crystals that have built its struture. Luthor's plan is to grow using the crystals a new continent in the Atlantic Ocean, that will eventually destroy North America. The first experiments have caused massive power outages, and Lois Lane, investigating the causes of the outage, inadvertently finds Luthor's base. She and her five year old son are made prisoners on Luthor's boat; Luthor takes them to sea where he uses one crystal and kryptonite to seed his new contient. Lois's son accidentaly makes a demonstration of his super-strength, and Luthor abandons them in the sinking ship. Lois's boyfriend attempts to save them, but gets trapped, and they are eventually saved by Superman. The latter then tries to catch Luthor on the newly grown island. Since its ground is laced with kryptonite, Superman is beaten by Luthor's goons and left for dead in the sea; e's saved in the nick of time by Lois and her family. Superman then lifts the island from the ground and throws it into space. He's however wounder by a shard of kryptonite, and ends up in a coma in the hospital. There, Lois reveals him that he's the father of her son. Soon after, Superman gets better, and Lois writes an article on “Why the world needs Superman”.

“fresh and tangy flavour and a light, citrus aroma”

Just another ale. Contains malted barley and malted wheat.

Hooker Brewery, Roscommon, Ireland. 4.3% alcohol.

Est-on moins mouillé si on court sous la pluie au lieu de marcher ? En modélisant un piéton comme un parallélépipède rectangle de hauteur h et d'épaisseur l, et en notant v_m la vitesse du piéton et v_p la vitesse de chute de la pluie, on obtient une vitesse v de la pluie relativement au piéton. Le vecteur vitesse fait un angle a avec la verticale. On peut alors calculer que la projection de la surface frontale du piéton dans la direction de ce vecteur est S_h, et la projection correspondant à la surface supérieur est S_l. Le produit de ces surfaces avec la vitesse de la pluie donne le débit d'eau, et si on multiple par le temps mis pour parcourir un trajet d'une longueur donnée d sous la pluie, on obtient le volume d'eau qui s'est déversé sur le piéton. Le détails des calculs est laissé en exercice au lecteur, mais le résultat est V = d(h + l v_p / v_m).

En conséquence, pour minimiser le volume d'eau V, il faut maximiser que v_m / v_p >> l / h. Si on considère un piéton de 1,80 m de hauteur et 0,3 m d'épaisseur, il faut que la vitesse du piéton soit plus grande que 1/6 v_p. Diverses sources sur le Web ont indiqué que la vitesse de la pluie en arrivant près du sol est d'environ 9 m/s, il faut donc que le piéton se déplace à plus de 1,5 m/s, soit 5,4 km/h.

In a near future, most people stay home and send surrogates (humanoid robots) outside to interact with other people, work, etc. It is supposed to be perefctly safe, but the son of Canter, the inventor of the surrogates, gets killed through his surrogate, despite the failsafes. FBI agent Tom Greer investigates, and manages to track the killer to a reservation where the few people who refuse to use surrogates live, led by a kind of prophet preaching revolution. Greer's surrogate is destroyed, and he is suspended. Greer decides to continue investigating, going out by himself, and discovers that the weapon is virus-based, had been made by the company making the surrogates for the army, but the project had been cancelled since it also injured the robot's operator. Greer also finds out that the killer was payed by his boss, and that the real target was Canter. During an army raid to the reservation in order to recover the weapon, the prophet is found to actually be a surrogate, controlled by Canter. The latter's goal is to kill all the people using surrogates using the hijacked surrogate of Greer's partner, through the FBI's not-so-legal network that allows to tap into anyone's surrogates. Greer prevents the virus from uploading to all surrogates, but uses the system to disable definitely all the robots.

Quatrième volume des aventures d'Oksa Pollock

Oksa et les Sauve-Qui-Peut sont de retour à Du-Dedans, sous le contrôle d'Ocious. Oska pénètre dans la chambre de la pèlerine et soigne le coeur des deux mondes. Elle réussit ensuite à s'enfuir, et rejoint les Sauve-Qui-Peut qui ont aussi réussi à échapper à Ocious, à Gratte-Feuillée. Les habitants protègent Oksa d'une attaque des Félons, durant laquelle Abakoum d'éclipse et profitant que Du-Mille-Yeux est vidée des félons, il construit avec l'aide des Corpusleox une bulle de protection. Après un filtrage à l'unique entrée, la ville ne contient plus que des personnes loyales à Oksa. Oska organise alors son gouvernement et entame la reconstruction de la ville, tandis que les Félons attanque régulièrement la bulle pour en éprouver l'efficacité. Oksa apperçoit un jour Tugdual discuter avec Mortimer, le fils d'Orthon. Elle apprend de Tugdual que Mortimer ne partage pas le point de vue de son père, et veut rejoindre Oksa. En gage de bonne foi, il a apporté une herbe qui pourra soigner la mère d'Oksa. Cette dernière décide alors d'aller dans le repaire des Félons pour voler la dernière fiole existante d'élixir Murmou qui pourra soigner Gus. Elle y assiste au meurtre d'Ocious par son fils Orthon, qui prend le commandemant des Félons. Aidée de Mortimer, qui a eu la même idée qu'elle, elle vole l'élixir et rejoint Du-Mille-Yeux. Elle annonce alors que le portail s'ouvrira bientôt, et les Félons qui n'attendait que cette occasion attaquent alors la cité, Orthon ayant l'espoir de retourner sur Terre. Les partisants d'Oksa gagnent la bataille et Orthon est tué. Peu de temps après, les Sauve-Qui-Peut de la lignée des Gracieuses, les seuls pouvant traverser le portail cette fois-ci, retournent sur Terre. Oksa découvre alors qu'Orthon s'était fait passé pour un Sauve-Qui-Peut (ce dernier ayant été tué par Orthon sous l'apparence de ce dernier, à la fin de la bataille) et a rejoint la Terre avec ses deux fils.

À la mort de leur mère, Gabrielle Chanel et sa soeur sont abandonnées par leur père à un orphelinat. Adultes, elles sont couturières le jour et chantent dans un cabaret le soir. Gabrielle, surnommée Coco à cause de la chanson qu'elle y chante rencontre Étienne Balsan, un homme riche. Coco n'est pas séduite par ce dernier, qu'elle trouve trop arrogant, mais lorsqu'elle se fait renvoyer du cabaret, elle va lui rendre visite dans son chateau, et s'incruste. Elle y rencontre nombre de riches qui lui font horreur, mais certaines femmes s'intéressent à ses chapeaux, nettement plus simples que la mode de l'époque, et elle en fabrique quelques uns. Coco refuse de porter les vêtements féminins en vogue, et s'habille plutôt comme un garçon. Chez Balsan elle fait la connaissance d'Arthur « Boy » Capel, un jeune homme d'affaire anglais dont elle tombe amoureuse. Ce dernier doit faire un mariage d'argent et elle refuse de l'épouser, mais ils restent amants, et Boy lui fournit les fonds nécessaires pour ouvrir une maison de couture à Paris. Il meurt peu après dans un accident de voiture, mais Coco persévère et réussit dans le métier.

“aromas and tastes of light bitter lemon, hints of subtle herb spiciness and a long hoppy finish”

Very strong first whiff of flowers (kind of honeysuckle?), quite bitter but very nice nonetheless. Contains malted barley and wheat.

Thornbridge brewery, Bakewell, Derbyshire, England. 3.5% alcohol.

“light biscuit palate… frsh, grassy aroma”

It reminds me a bit of apple juice, otherwise just another ale, not bitter at all.

Black Isle Brewery, Black Isle, Highlands, Scotland. 4.5% alcohol.

Twenty-five years ealier, MiB agent K has refused to help Queen Lauraana and keep the Light of Zartha on Earth; the treasure was sent back, preventing at the same time Serleena to put her tentacles on it. Now K has left the agency and works at a post office. But Serleena is back on Earth and is looking for the Light of Zartha, and K is the only one who knows where it is. J therefore de-neutralizes K and allows him to recover his memory, but the latter had neutralized his memories of the Light of Zartha twenty-five years ago and cannot remember, he only left a set of clues for himself. Meanwhile, Serleena had killed the owner of a pizza shop (that happens to be related to the clues leading to the Light of Zartha) and J didn't want to neutralize his employee, Laura. The latter therefore tags along with J and K. Serleena then invests MiB headquarters, that is therefore locked down, J and K are on their own. Serleena finally concludes that the Light is in Laura's bracelet, but after defeating Serleena, K reveals that the Light is still on Earth, that Laura *is* the Light of Zartha, and that she has to leave Earth before midnight or the planet will be destroyed. K also hints that Laura could be his and Lauraana's daughter.

Just another ale. Contains malted barley.

Fuller, Smith & Turner, London, England. 5.3% alcohol.

Jackie, an orphan, is contacted by a private detective who tells him that his father, a wealthy Korean man and a former spy, is still alive but dying, and wants to give him his inheritance if he can follow the clues. Jackie ends up in Turkish bank where he retrieves a large sum of money and a small package. He soon gets attacked but fences off the thugs. Then he meets two women: Carment, a Koran reporter and Yong, whose scarf is embroidered with the same text as one of his father's clues, before being attacked again. The reporter happens to actually be a CIA agent and she tells him that the thugs are after a plant producing a super-opium. The other woman appears to be working for Lee, a crime lord, to whom Jackie's “father” had promised the plant. Jackie escapes Lee's clutches, and the latter offers Jackie the life of the woman in exchange for the plant. Jackie eventually finds out the location of the plant (2 vials, hidden by a Turkish priest, friend of his “father”) and gives it to Lee. Jackie tells Carmen what he has done, but as Yong dies, he tries (and after a long car/truck chase, manages) to recover the vials, but is severely wounded. Waking up in hospital, he is told by the “private detective” (actually a US agent) that this was all an intelligence mission with Jackie as the main agent to recover the plant.

“classic country ale… First Gold are dwarf hops that grow in log hedgerows… hints of orange and spice from the hop”

Orange? maybe, not really convinced. Bitter but not too much. Just another ale.

Hall & Woodhouse Ltd., Blandford, Dorset, England. 4.0% alcohol.

“pithy bitterness, malty backbone and lemon and lime aroma”

Quite bitter (but reasonnably so); the first sip tasted a lot like lichi in my opinion. Contains malted barley.

Adnams, Southwold, Suffolk, England. 4.5% alcohol.

This is, in a nutshell, how to send commits to the (single) maintainer of a project by e-mail.

Add the maintainer's e-mail address to the repository's config:

git config --set sendemail.to "John Smith <john.smith@example.com>"

Make a set of patches from the commits e.g.,

git format-patch HEADˆ

or

git format-patch origin/master..master

Send the patches by e-mail:

git send-email *.patch

(this sends one e-mail per patch).

On the receiving side, the maintainer can then feed the content of each e-mail into git am to apply the patches and record new commits.

The git send-email command is packaged separately in Debian, the package git-email needs to be installed.

This post is based on this page from the Chromium project.

Resolve a binary file conflict with Git

Found on lostechies.com

In case of conflict with a binary file during a merge, you have two choices for resolving it:

• Use your own version:

  git add thefile

• Use the other version:

  git checkout --theirs -- thefile; git add thefile

Then commit the changes.

Show the content of a deleted file

Found on stackoverflow.com

git show commitid:path/to/file

The trick here is that one must use the full path to the file (relatively to the repository's root)

Restore a deleted file in a Git repo

Found on stackoverflow.com

Find the last commit where the file was deleted:

git rev-list -n 1 HEAD -- thefile

Then checkout the file from the commit before that:

git checkout commitid -- thefile

“sweet nutty palate, hoppy aroma and a hint of Seville oranges”

Just another ale, but quite good. Contains malted barley.

Hall & Woodhouse Ltd., Blandford, Dorset, England. 4.4% alcohol.

Je me suis récemment intéressé aux jeux de dés, et j'ai découvert Zombie Dice. Le principe est très simple, le jeu est rapide, mais le thème ne me plaisait pas. Alors j'ai décidé de changer le thème en Super Mario. J'avais d'abord songé au Super Mario Bros. original tournant sur NES, mais je trouvais les graphismes de la réédition pour SNES (Super Mario All Stars) nettement plus beaux, et donc j'ai repris les graphiques de cette version là.

Les dés viennent de blankdice.co.uk, chez qui j'ai déjà acheté un certain nombre de dés. Les faces ont un léger creux, qui permettent de coller un autocollant carré de 14,5 mm de coté. J'ai imprimé sur un autocollant au format A4 et découpé les carrés avec un cutter rotatif sans trop appuyer, ce qui permet de couper l'autocollant sans couper le papier-support et donc de décoller les petits autocollants bien plus facilement.

Zombie Dice est vendu sous blister et ne comprend qu'un gros gobelet et 13 dés. Il nécessite quelque chose pour marquer le score (papier/crayon, jetons…) J'ai donc fabriqué une piste pliante de 13 cases plus une case départ, encore une fois en imprimant sur un autocollant A4. À la place du gobelet, je vais fabriquer un sac en tissu, assez grand pour contenir tous les composants (il reste à trouver le tissu).

Une amie m'a proposé de fabriquer des pions en forme de personnages de Super Mario en échange de quoi je lui fabrique quelques copies du jeu. On verra ce que ça donne.

While scanning phone numbers in the hope of accessing a game company's server, David Lightman unknowingly connects to W.O.P.R., a computer that integrally and automatically controls the USA's response to a nuclear attack (this scheme was implemented after the military noticed that 20% of the personel affected to missile launching was unwilling to actually launch them). The computer lists games, from chess and backgammon to global thermonuclear war. One of the game's title hints that Stephen Falken had programmed the computer. Falken had disappeared mysteriously, and David, convinced there is a backdoor in the system, spends a week out of school trying to figure out the secret password, which happens to be “joshua”, Falken's dead son. David then asks the computer to play global thermonuclear war, without noticing that he started a simulation that made the militray at NORAD believe that USSR was actually attacking. The military manage to understand that no such attack is actually happening, but the computer continues its simulation, and through a TV broadcast, David discovers what he has done. He is arrested by the FBI and brought to NORAD, where he discovers that Falken is still alive and lives under a false identity. David escapes NORAD with a group of tourists, and with the help of his friend Jennifer, visits Falken. The latter refuses to help them at first, but eventually goes with them back to NORAD. There the military have lost control of the situation and truly belive the soviets have launched their missiles. David then makes Joshua play tic-tac-toe agains itself, and the computer then notices that there are games that cannot be won. It then plays all possible scenarios of thermonuclear war and learns that the same applies to that game. The computer relinquishes control of the missiles just in time.

“a blend of traditionally crafted beer infused with Cider Apples”

Smells good, very sweet, even too much. But it has this I-don't-know-what taste I don't like in some styles of beers, and mixed with the over sweetness, it made me a bit queasy.

Wychwood Brewery Co. Witney, Oxfordshire, England. 4.2% alcohol.

Peter works as an unhappy software developer, in a company plagued by bureaucracy and uncaring managers. One day, his girlfriend takes him to a session with a hypnotherapist. The latter has a heart attack in the middle of the session, leaving Peter in an out-of-character state. Peter then decides not to care about work anymore, and becomes much happier at work. He even gets promoted, while two of his friends are kicked out. Together, they decide to plant a virus into the company's accounting system that would re-route the fractions of cents normally rounded down to their bank account. But because of a mistake in the virus, much more money than what they expected gets transferred. No knowing what to do and facing jail time, Peter decides to return the money to the company and to take all the blame. But another disgruntled worker (he had been laid off five years earlier, but because of a glitch in payroll software, continued to be paid; the management decided to repair the glitch, but didn't tell the guy, and moved him to an “office” in the basement) finds the checks Peter slipped under his manager's door and takes the money before setting fire to the company. All traces of the fraud has disappeared in the fire, and Peter is much happier in his new job as a construction worker.

“Fugles and Challenger hops plus a blend of 4 local barley malts… dark chocolate cream stout… bittersweet aftertaste”

Defintely chocolaty, and with a hint of the strange fruity taste found in the the brewer's Honey Porter beer. Oddly, the aftertaste sometimes (but not systematically) reminds me of a cold ashtray.

St. Peter's Brewery, Bungay, Suffolk, England. 6.5% alcohol.

“a combination of five different malts, some heavily roasted for a near jet black appearance… red berry notes, toasty aromas and a dry, bitter finish.”

Just another stout, tastes clearly of roasted malt, but red berrys? Contains malted barley.

Fuller, Smith & Turner, London, England. 4.5% alcohol.

Conan's people are killed by Thulsa Doom's warriors, who are seeking steel. Conan is taken as a slave and eventually grows very strong. He's then trained to be a gladiator, and later freed by his master. Conan then searches for his people's crest in the hope to find Thulsa Doom and avenge his parents. He befriends two thieves, Subotai and Valeria, and together they steal a large jewel from the Tower of Serpents. Thulsa Doom has become the leader of a powerful cult and the Tower of Serpents is home to some of his followers. King Osric then asks the three adventurers to bring his daughter back from Thulsa Doom's influence. Conan leves alone on his quest, but is caught by Doom and left to die. He's saved by his two friends who have eventually decided to join him on his quest. They sneak into Thulsa Doom's temple and free the princess. Doom attacks their camp to retrieve the girl, but fails; when he attempts to kill the princess, the latter finally understands that Doom is a monster and wants to go back to her father. Valeria was killed in the attack, and Conan then sneaks back into Doom's temple and kills him while the latter is addressing his followers.

“thrice hopped with three types of hop… Goldings and Cascade combine to provide a citrus-grapefruit and floral aroma, while First Gold carries the bitterness… match with roast lamb and spicy Thai dishes”

Very flowery, only slightly bitter, overal quite good. Contains malted barley.

Hall & Woodhouse Ltd., Blandford, Dorset, England. 4.4% alcohol.

In 2018, two Americans land on the dark side of the Moon, officially in an attempt to promote the reelection of the president, and unofficially to search for helium 3. They discover a large industrial complex, built by the Nazis who had fled Earth in 1945. One of the astronauts is killed, but the second one, James Washington, is taken prisoner. There he meets Renate Richter, the daughter of the local mad scientist. Renate's father finds out that Washington's mobile phone is way more powerful than their computer, and is exactly what they need to power the Götterdämmerung, a gigantic space ship meant to take over the Earth. Renate is kind, has a naive understanding of the Nazi ideology, and she wants to help Washington return to Earth. Following her advice, the latter pretends to have succombed to his brainwahsing, and accompanies Klaus Adler, who wants to become the next Führer as soon as possible. Upon their arrival in New York, Adler and Renate accidentally meet the PR agent of the president who sees in them a possibility for getting the president reelected, promoting the positive aspects of Nazi ideology. After a few months, the Führer arrives on Earth and confronts Adler, having discovered his plan, but gets killed. The space-Zeppelin fleet that has been following him however starts launching an attack on New York. Adler returns meanshile to the Moon with a load of mobile phones for powering the Götterdämmerung. The president of the USA is thrilled by the war, which should ensure her reelection. At the UN, she discusses the space attack, and it turns out that every nation has weapons in their spacecrafts (except Finland) ; their joint armada defeats the Zeppelins, then bombs the Moon base and turns to the Götterdämmerung. Meanwhile, Renate and Washington have flown back to the Moon as well and sabotage the huge ship, killing Adler in the process. Renate and Washington decide to stay on the Moon, re-educating the locals to teach them about tolerance, while the nations of Earth fight each other for the control of the reserves of helium 3 from the Moon.

Neuvième volume des Arcanes du Midi-Minuit publié en 2012. Trois kamikazes font exploser leurs bombes simultanément dans des lieux publics, mais les attentats ne sont pas revendiqués. Des témoignages conduisent les enquêteurs du bureau royal sur la piste d'un patron de la pègre, mais d'autres rapportent que les kamikazes avaient un regard étrange. Ce dernier fait conduit les enquêteurs à soupçonner un hyptnotiseur qui est justement en tournée dans la ville. On découvre à la fin que le père de ce dernier, un hypnotiseur encore plus puissant que son fils, est à l'origine des attentats. Il veut ainsi se venger le massacre de sa famille, durant une guerre civile qui a eu lieu des années auparavant que l'armée du Roi aurait pu empêcher mais ne l'a pas fait parce qu'elle avait promis de rester neutre durant le conflit.

“Hops are added late in the brewing process… refreshing citrus aroma and flavours… pairs best with light flavours such as white fish and cheese”

Very nice, flowery smell, with a hint of fresh bread. Contains barley malt.

S.A. Brain & Co. Ltd., The Cardiff Brewery, Cardiff, Wales. 4.7% alcohol.

For my car heater controller I decided to use Alan Burlison's scheduler. I like it, because it leaves the main program file reasonnably short and allows to separate the code into multiple objects. I don't know if it makes the software more or less easy to write/maintain, but I find it fun to do it this way, and that's all that counts.

To implement 2-way communication between the JeeLink (master) and the JeeNode (slave) using Jean-Claude Wippler's RF12 library, I created a Listener object and a Speaker object that deal with receiving data and sending data respectively, while the Protocol object implements the higher-level protocol.

Here' how the slave's .pde file looks like. Notice how it contains only definitions and a bit of initialization, but no big mess of code?

#define NB_ELEMENTS(a) sizeof(a) / sizeof(a[0])
 
Speaker speaker;
Protocol protocol(&speaker);
Listener listener(&protocol);
 
Task * tasks[] = { &listener, &speaker };
TaskScheduler scheduler(tasks, NB_ELEMENTS(tasks));
 
void setup() {
  rf12_initialize(SLAVE_ID, RF12_868MHZ, HEATER_GROUP);
}
 
void loop() {
  scheduler.run(); // infinite loop
}

Here's a sample of the slave's Listener.

class Listener: public Task { // Task from Alan Burlison's scheduler
    public:
    Listener(Protocol * protocol):
      protocol(protocol)
      {};
 
    bool canRun(uint32_t now); // Taks's interface
    void run(uint32_t now);    // Task's interface
 
  private:
    Protocol * protocol;    // higher-level protocol handler
    uint8_t recv_buffer[BUFFER_LEN];
    uint8_t recv_buffer_len;
};
 
bool Listener::canRun(uint32_t now) {
  if (rf12_recvDone())
    return (rf12_crc == 0 &&  rf12_len <= BUFFER_LEN);
  return false;
}
 
void Listener::run(uint32_t now) {
  recv_buffer_len = rf12_len;
  memcpy((void *)recv_buffer, (void *)rf12_data, recv_buffer_len);
  if (rf12_hdr == (RF12_HDR_CTL | (MASTER_ID & RF12_HDR_MASK)))
    protocol->got_ack();
  else {
    if (RF12_WANTS_ACK) {
      rf12_sendStart(RF12_ACK_REPLY, 0, 0);
      rf12_sendWait(0);
    }
    protocol->handle(recv_buffer, recv_buffer_len);
  }
}

And there's the slave's Speaker. Note that the Spaker tries to send data only if its buffer_len is greater than zero. This prevents calling rf12_canSend() when it's not necessary (according to the RF12 driver, you must not call rf12_canSend() only if you intend to send data immediately after calling it). When the Protocol wants to send something, it needs to get the Speaker's buffer with get_buffer(), fill the buffer with data, and then call send(). Also, I implemented a retry mechanism in case no ACK has been received from the master.

class Speaker: public Task { // Task from Alan Burlison's scheduler
  public:
    Speaker();
    uint8_t* get_buffer();
    void send(uint8_t len, bool ack);
    void got_ack(); // called by the Protocol when it gets an ACK
    bool canRun(uint32_t now);  // Task interface
    void run(uint32_t now);     // Task interface
 
  private:
    uint8_t buffer[BUFFER_LEN];
    uint8_t buffer_len;
    bool with_ack;
    uint8_t retry_count;
    unsigned long next_retry_millis;
};
 
bool Speaker::canRun(uint32_t now) {
  if (buffer_len > 0 && retry_count > 0
                     && millis() > next_retry_millis)
    return rf12_canSend();
  return false;
}
 
void Speaker::run(uint32_t now) {
  if (with_ack && retry_count == 1) {
    buffer_len = 0;
  }
  uint8_t header = (with_ack ? RF12_HDR_ACK : 0)
                  | RF12_HDR_DST | MASTER_ID;
  rf12_sendStart(header, buffer, buffer_len);
  rf12_sendWait(0);
  if (with_ack) {
    retry_count  – ;
    next_retry_millis = millis() + SEND_RETRY_TIMEOUT;
  }
  else
    buffer_len = 0;
}
 
void Speaker::send(uint8_t len, bool ack) {
  with_ack = ack;
  buffer_len = len;
  retry_count = SEND_RETRY_COUNT + 1;
  next_retry_millis = millis();
}
 
void Speaker::got_ack() {
  buffer_len = 0;
}

The master's code is very similar, you can check it there.

Finnish winters are cold, and petrol engines don't like starting when it's very cold. That's why cars are often equipped with an electric heater that preheat's the cooling liquid for some time before starting the engine. The duration of this pre-heating depends on the temperature (in French). Moreover, since I don't leave home every morning at the same time, I don't want to start heating the car at the same time every day, even if the outside temperature doesn't change much from day to day. Hence this project of a remote-controlled switch for the car heater.

The system is composed of two Arduino-compatible parts: one master, connected to the home computer (always on), and one slave, in the garage. The master is a JeeLink and the slave is based on a JeeNode. Master and slave communicate with each other with a radio (868 MHz, a free Low-power_communication_device band in Europe).

The master

Not much to say about the master, the hardware is a standard JeeLink, which for the purpose of this project is really only a radio transceiver on a Serial-over-USB interface.

The slave

The electronic is very simple, and only a few components are needed. I paid special attention to selecting components that are specified to work from -40 °C (although I have no idea how well the device works at that temperature).

The slave is organised around a JeeNode (vertical, in the right-hand corner of the picture), and has the following three features.

It controls a relay (the black box above the orange PCB on the picture), which can be open or closed.

It measures the outside temperature with a DS18S20 sensor.

It measures the current flowing out of the relay using a current transformer (the black ring aroung the brown wire on the left side of the picture).

Moreover, it has a power supply (the black box on the lower left corner of the picture).

You can also notice that the mains cable (a 5 m, outdoors prolongation cord) has an earth wire that has not been severed. The live (brown) and neutral (blue) wires have been cut and connected to the relay. Power for the power supply is taken from the plug-side of the cable, before the relay (so it's always connected to the mains).

Power supply

The power comes from a compact switching power supply that converts 230 V AC into 12 V DC (maximum output power: 4 W). In case the power supply fails, the 1 A fuse (in the holder on the big red wire on the lower-left corner of the picture) should blow before the whole thing catches on fire. Also, although the power supply is designed to be placed on a PCB, I decided not to have any 230 VAC on the PCB, so I soldered the wires straight to its input pins, and isolated them with heat-shrink tube and added epoxy for strenght (the pins are not so strong, I don't want to break them once they are connected to the thick and not-so-flexible wires).

The relay requires 12 V, hence the output value for the power supply. The JeeNode requires a 3.3 V supply, and the onboard voltage regulator could take the 12 V, but would ouput only a low current (less than 100 mA). By adding a 5 V regulator (7805) to supply the JeeNode, the latter can get more current from its on-board regulator.

Relay

The relay (specified to switch up to 400 VAC and 30 A) requires 160 mA to be activated. It is therefore controlled via a BC337 transistor, which is strong enough to withstand the current. The base of the transistor is connected to one digital pin of the JeeNode via a 2 kΩ resistor, which allows to open or close the relay by applying a High or Low signal to that pin.

Temperature sensor

The DS18S20 transmits the temperture information digitally over a 1-Wire bus, and therefore requires really nothing more than a 4.7 kΩ pull-up resistor. It works quite happily with 3.3 V at the end of a 15 m cable (an old phone extension cord). Note that since I have three wires in the cable, I didn't even try to power the sensor with parasitic power (anyway, I read somewhere that it doesn't work well at 3.3 V). The Arduino OneWire library does all the work for you, all you need is to connect the data pin of the sensor to one digital input of the JeeNode.

Current sensor

Finally, the current transformer is placed around the live wire coming out of the relay. The design is based on a page at OpenEnergyMonitor that does not appear to exist anymore, but this one should give a good start.

Basically, the current transformer produces a current (not a voltage) that is proportional (depending on the number of turns, my transformer has 1012 turns) to the current flowing through the mains wire that goes through the transformer. A burden resistor (68 Ω in my case) across the two wires produces an AC voltage that is proportional to this current and varies between -1.65 and +1.65 V (corresponding to mains current between -23 and +23 A peak-to-peak). Then one wire of the transformer is connected to a voltage divider made of two 20 kΩ resistors (with a filtering 47 μF capacitor) and the other wire goes to one of the analog inputs of the JeeNode. This way, the analog input sees a voltage that varies between 0 and 3.3 V, which is within the tolerance of the device.

After that, the software samples the analog value 3000 times, applies a high-pass filter to remove the DC offset, and simple math computes the RMS current. After a bit of calibration (using a 60 W lamp, and 500 W halogen lamp, a 1400 W flat iron and a 2300 W electric kettle, and comparing my measurments against those of a wattmeter), I noticed that the reported current is quite accurate (to about 0.01 A, which is more than enough for my purposes).

Box

The PCB and the relay a screwed on a piece of plexiglas, and the whole device is placed in a project box to protect it from dust. Zip ties around the cables near the holes prevent the cables from being accidentally pulled out of the box.

Schematics

The schematics are available as a PNG picture, and in Eagle format. Note that since I used strip board to assemble the circuit, I haven't paid attention to choosing the right component packages, nor the right type of component. The Eagle schematics is therefore provided for information purposes only, generating a board from it is not going to produce correct results.

The Software

It's all available there. You can obtain it with git using the command

git clone http://weber.fi.eu.org/software/arduino/heater_controller/.git/

Scaling the solar system down to human sizes leads to more interesting comparisons. Let's assume the Earth is the size of a pin head (2 mm in diameter). We then have the following results:

• A human being living on the surface of the pinhead would be 0.30 nm (the size of two dihydrogen molecules)
• Mount Everest would be 1.4 μm tall (1/5 of the thickness of a strand of spider's web silk)
• Geostationary satellites would orbit the pin head at 5 mm from its surface but the International Space Station would be at only 60 μm from the surface (the thickness of a hair)

• A lightyear would be 1500 km long (the distance between Copenhagen, Denmark and Rome, Italy), so the closest star (Proxima Centauri) would be 6600 km away (distance between Paris, France and New Dehli, India, or between New York, USA and Berlin, Germany)
• The Oort cloud would be 3000 km in diameter (the distance between Madrid, Spain and Helsinki, Finland, with the volley ball representing the Sun located somewhere near Cologne, Germany)
• The diameter of the Milky Way (our galaxy) would be equivalent to the distance between the Sun and Earth
• The whole universe would be 20·10¹² km in diameter, that is 2 lightyears (diameter of the Oort cloud, or half the distance to Proxima Centauri)

The solar system is big, that's well known. But how big, exactly?

Let's assume the Sun is the size of a volleyball (about 21 cm in diameter). We would then have the following relative planet sizes and distances to the ball:

• Mercury: 1 mm diameter (a small pin head), 9 m from the ball (a bus)
• Venus: 2 mm diameter (a pin head), 16 m from the ball (a semi-trailer truck)
• Earth: 2 mm diameter (a pin head), 23 m from the ball
• Mars: 1 mm diameter (a small pin head), 35 m from the ball (a blue whale)
• Jupiter: 22 mm diameter (a walnut), 120 m from the ball (maximum length of a football/soccer field)
• Saturn: 19 mm diameter (a smaller walnut), 220 m from the ball (one TGV train)
• Uranus: 8 mm diameter (a cherry's kernel), 460 m from the ball (a double TGV train)
• Neptune: 8 mm diameter (a cherry's kernel), 700 m from the ball (length of the Avenue de l'opéra, Paris, France)

By comparison, the Moon would be 0.5 mm in diameter (a grain of sand) and 6 cm from the pin head (the length of the little finger).

My daughter asked me yesterday what is the largest number I know. The answer was “a Googolplex”, which is 10^googol with googol = 10¹⁰⁰.

While you can write a googol on a sheet of paper (it's a one followed by 100 zeros), you cannot write a googolplex on paper. Or can you? how much paper do you need for that?

Let's assume you can write 10 000 digits on one sheet of A4 paper. You therefore need 10⁹⁶ sheets of paper. One tree can produce 10 000 sheets of paper, and there are about 10¹² trees on Earth. You'd need 10⁸⁰ Earths to provide all the paper. Not going to work.

Now let's see if there's even enough matter in the universe to make all this paper: assuming that all the matter in the universe can be converted to paper, is there enough of it? Paper is made of cellulose, chains of D-glucose, the latter weighing 128 g/mol. So a 5 g sheet of A4 paper contains about 2.5·10²² molecules of linked D-glucose, each of which is made of 128 hadrons (protons and neutrons). A sheet of paper is therefore made of 3·10²⁴ hadrons, which is almos the same thing as an atom of hydrogen. The universe contains roughly 10⁸⁰ atoms, which translate roughly as 10⁵⁶ sheets of paper. We'd need 10⁴⁰ universes to make all the needed paper. Not going to work either.

That was a very big number.

The disembodied mind of Jean le Flambeur, a famous thief, is forever prisoner and forced to play the Prisoner's Dilemma until he learns to cooperate. One day he is extracted by Mieli (a Sobornost) from the prison and given a new synthetic body made of another kind of material, which is however under Mieli's control. During the escape, a piece of Archon, the replicating, smart material the prison is made of gets trapped into Jean's body. Mieli then takes him to Mars, where he is supposed to steal something on behalf of Mieli's goddess, the pellegrini. Mars is the home of the Oubliette, a city moving on gigantic legs that eternally flighs before the phoboi, dangerous self-replicating weapons that infestate the surface of the planet, left over of the Mars civil war. In the Oubliette, people have a limited lifetime as Nobles, after which their mind is transfered to mechanical bodies and they start a period as Quiets, working to maintain the city, before stating a new Noble/Quiet cycle; time (to live) is the local currency. There is also a global exomemory used by everyone, where personal memories are controlled by private cryptographic keys. In the Oubliette, Jean finds out he used to live there under the name of Pierre Sernine, but has somehow lost his memory. With the help of the technology available to Mieli, he manages to steal one minute of the life of Christian Unruh, a man who became very rich in time and has never gone through the Quiet stage who had decided on the precise time when he would die. A local detective, Isidore Bautrelet, investigates the theft and starts following le Flambeur's trail. After Unruh's body has been transfered to a machine, Jean and Mieli inspect his mind, and discover that it has been tampered with during the transfer, and conjecture that everybody's mind in the Oubliette has been tampered with by the cryptarchs who secretely rule the city. When the news spreads (along with a protection against the security hole made by the cryptarchs), riots start on the street and between the Quiet who keep the city moving forward, and the city stops progressing, in danger of being caught up by the phoboi. Meanwhile, Jean recovers traces of his past, and discovers that he had split hie memories into nine pieces. When he has to decide whether he should recover his past memory and decides not to, the king of the Oubliette (a copy of Jean's mind from before he went to prison) does it for him. The Oubliette actually used to be a prison (a virtual Panopticon) and Jean le Roi was an inmate who, with the other cryptarchs, managed to hack into the panopticon system and use it for getting power over the other inmates. A catastrophe wiped out all traces of their doings, and in time le Roi wiped out the other cryptarchs. They also got help from Zoku refugees, a warrior collective that lost a war against the Sobornost. Le Flambeur and le Roi eventually fight and the piece of the prison in the former's body starts to build a new prison around the latter's mind, while Mieli saves le Flambeur in the nick of time.

“hint of ginger and citrus”

Not as heavily sweet and gingered as other ginger beers, this one is even slightly bitter. Contains barley malt.

Little Valley Brewery, Hebden Bridge, West Yorkshire, England. 4.0% alcohol.

Holmes arrests Lord Blackwood, a practitioner of black magic who has killed several persons. He is sentenced to death, hanged, and Watson pronounces him dead. He has however warned Holmes on the day of his execution that something bigger than him was going on. Holmes is then asked by Irene Adler (who is working for a mysterious man) to find a midget with ginger hair. The man is found in the coffin on Lord Blackwood, who has been seen earlier that day coming out of his grave. Holmes is then asked by important members of the government to stop Blackwood. They reveal that they (and Blackwood) are members of a secret society that controls all key areas of the British Empire. Soon after, a few of them are killed in mysterious circumstances that look like sorcery. Holmes then tricks one member of the society, secretly working with Blackwood, into reavealing their plan: killing all the members of the Parliament who don't want to follow Blackwood in his conquest of the world. A wirelessly-triggered machine that will deliver poison to the Parliament's ventilation system is hiddenn in the sewers. With the help of Watson and Irene Adler, Holmes prevents the poison to be released, and eventually gets Blackwood killed. He also learns from Irene that she is working for Moriarty, and her escape with the poison part of the machine was just a diversion allowing Moriarty to steal the wireless component fo the device, which is what he was really after. Holmes finally explains that Blackwood was not a real sorcerer and that all was made with tricks.