ATtiny based altimeters

I am working on a couple of altimeters using the ATtiny 84 and 85 microcontrollers. The idea is to be able to have some smaller devices that can work in low power rockets.

Those are the altimeters I am working on

Preparing the dev environment

First of all you need to patch the Arduino ide so that you can use the ATtiny microcontrollers.

You need to download the following files:

attiny-master.zip

tinyBMP085

TinyWireM

TinyWireS

The attiny has to go to your hardware directory. It is better to create a hardware directory under your sketch directory.

If you do not know where your sketch directory is go to File->Preferences

so the directory structure is:

[your sketch dir]/hardware/attiny

The tinyBMP085,  TinyWireS and TinyWireM have to go in your libraries directory. Again put them under your sketch directory.

so the directory structure is:

[your sketch dir]/libraries/tinyBMP085

[your sketch dir]/libraries/TinyWireM

[your sketch dir]/libraries/TinyWireS

Patching the linker

The linker has a bug with the attiny microcontroller which stop it to work with program greater than 4K so you need to download a patched version.

Compiling the programs

You can download the programs here. They will compile only after you have downloaded and installed the tiny libraries.

I have tried to optimise the code because the ATtiny 84 and 85 microcontrollers have only 8k of memory. Just rewriting a more efficient pow function saved 1k of memory.

Open the program and the select the appropriate microcontroller.