The microcontrollers

The heart of the project is based on the microcontrollers progress. These cheap integrated circuits (few euros) are like tiny computers used in cars, DVD players, microwave ovens, etc ...

Some microcontrollers integrate Analogic to Digital Converters (ADC) which allow to measure a voltage (at the feet of a sensor for example)  and deduce a physical value (temperature, pressure, humidity, etc ...). There  are many  microcontrollers manufacturers. There are even microcontrollers you can program in BASIC but they are often expensive and slow.

For our first prototype we have chosen the AVR family from ATMEL manufacturer. These microcontrollers have many  advantages:

- very fast (RISC Technology)
- excellent ratio price/quality (from 3€)
- can be programed with good Free and Open Source software on Windows, Linux (and Mac ?)

The microcontroller we use is the atmega8 that we can find from 3€ (see picture above).

For this price you have in particular:

- 23 possible digital input/output (switch on LED, "read" a switch...)
- 6 Analogic to Digital Converters (ADC) 10 bits
- a serial interface (RS232) to communicate with your PC
- up to 16 MIPS (million instructions per seconds) processed
- an internal clock up to 8Mhz
- Flash memory, RAM, ROM, EPPROM, etc...

In order to work the microcontroller need to be nested in an electric circuit (which can be more or less complex depending on what we want to achieve). For this we designed the "Liberlab" card (see the card section).
You will also need to give a brain to the microcontroller: the firmware software (see the firmware section).