Tag Archives: GPIO

Heat and humidity control

Winter… (well, at least  as it should be)


When you awake, the house is cold – only 15.5 ºC! – and dry…


Hopefully, it is possible to boost the heating system: an efficient solution is to add a fan in front of a radiator. Then it is warmer but definitely too dry – only 26%!


This is mere physic: a warm air can absorb more humidity and heating doesn’t add humidity.

Hopefully, it is possible to humidify the air: an efficient solution is to add an humidifier, next to the fan.


Then it is too wet – 48%!


Hopefully, it is possible to control the humidifier: an efficient solution is to add an humidity sensor to a remote outlet controller.

SHT1XThen the percentage of humidity is at last perfect – 40%.

TropChaudYet, it is a little too warm…
Hopefully, it is possible to control the fan: an efficient solution is to replace the big and very noisy fan by a tiny yet powerful very silent fan specialized for PC cooling. SilentFan


Eventually the temperature and humidity is under control 🙂




A Raspberry Pi Zero turned in a HomeEasy RX/TX


Last post about the relaxing geek was just a simple preparatory step for a more challenging project: controlling domotic devices with a open computer.

Incidentally, it was a perfect opportunity to illustrate the thought about what is better than open source. Many thanks to Gordon Henderson (UK, Devon) for his well documented Wiring Pi. It has proven the most helpful resource for this project, unlike all the misleading false information so easily found on the HomeEasy protocol. Actually, the same protocol is also used by many home automation brands: Chacon, DI-O, TellStick, Zibase, My FOX, RFXCom and much more.

Apart from the Raspberry Pi Zero, the main component used for this project is the RTX-MID-5V from Aurel SPA (Italy, Modigliana). This is an RF digital data transceiver working on the ISM free-license band of 433.92 MHz, in half-duplex way. Only the transmission feature was looked for in this product but its receiving capabilities helped a lot in understanding the HomeEasy protocol.

Of course the RGB LED played its useful part:

  • Red to monitor the direction, TX: on, RX; off
  • Green to monitor the data received 1: on, 0: off
  • Blue to monitor the data sent, 1: on, 0: off

The Proof of Concept is successful. Yet there is more to come. Being able to remotely control up to more than 134 million home automation devices from a computer opens an infinite range of possibilities for a geek:

Moreover, controls of all those devices can be synchronised and linked to other sensors. For example, the light is turned on when the shutters are closed and off when they are opened, depending on the time of the day and the ambient light detected by a light sensor.


Relaxing geek

pzgpiohwHaving finished a tough job in an even tougher schedule called for a welcomed rest.

The Raspberry Pi Zero was lurking on its hacking stand and a RGB LED was longing to be used in a cupboard…

Every conditions were thus set to build this mighty project: a multi coloured blink. It’s the equivalent of the famous “Hello world!” to the realm of GPIO.

Jeux de geek


Jeu du presse-bouton

Règles du jeu

Les 4 diodes de couleur rouge ou verte s’allument au hasard. Il faut les éteindre le plus vite possible en appuyant sur les boutons rouge ou jaune correspondants, placés à droite des diodes et ordonnés à l’identique.

Eléments du jeu

  • A gauche sur la photo : un Raspberry Pi, un ordinateur complet de la taille d’une carte de crédit. En l’occurrence, il sert à piloter les diodes par l’intermédiaire de son interface GPIO.
  • A droite : une platine d’essai avec un montage électronique à base de diodes, de résistances, de boutons pressions et de mini câbles de raccordement.
  • Entre les deux : une nappe de raccordements pour connecteurs 26 broches.

Et, oui, quand on passe ses journées devant son ordinateur à taper sur son clavier, le faire devant des iodes sur quatre boutons, forcément, cela détend !

A vrai dire, le vrai geek s’amuse davantage à concevoir, réaliser et programmer ce jeu qu’à y jouer. Que voulez-vous…