A miner’s canary(‘s) cage

The gas sensors and stepper door control are now together, sensing high levels of Carbon Monoxide or Methane will open the bird cage door (See previous post). I put in a small push button to act as a test switch- like on smoke detectors. I don’t think it is quite ready for a bird just yet. Need to take it off the breadboard and put it onto something more permanent and clean up the wires. Thought it would also be good to put clear acrylic behind the electronic components- so the canary can’t attack the exposed parts.

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Canary in a Coal Mine: In two parts

I am taking a miniature break from my Sims Needs Meter, to make a carbon monoxide and methane gas sensor unit for a canary cage.

Today it is in two parts, hoping to put them together tomorrow. First part is the arduino powered cage door:

Above is a unipolar stepper being driven by a darlington array. I am just using the stepper example in the arduino ide. There are a few different versions- one step, full rotation etc. Arduino reference for wiring a stepper. The stepper has a small robot wheel attached to it’s shaft- which i have glue some fishing line to. The groove in the wheel is designed to fit a small rubber tire into it- but here it is perfect for the fishing wire to be wound up onto it. And that is about it. Super simple. Now to find a way to attached it to the bird cage that does not involve gaffa tape.

And the second part is the:  Carbon Monoxide (Top) and Methane (Bottom) sensors:

These sensors are soldered to the sparkfun gas sensor breakout boards, and using a simple analog read to extract data. There are very limited tutorials available for gas sensors, unless you are making a breathalyser or fart-meter. So after I put these two parts together, I will attempt to create a comprehensive tutorial. Still searching for some more info on calibration and interpreting the readings.

Arduino Flip Clock

This is an old work I had started a while ago, hope to finish it soon. It is an arduino connected to a old flip clock. Clock is connected to a stepper motor (stepper tutorial)– delay time is determined by the pot. The steppers steps and the clock gears don’t match up, so next thing i need to do is make some gears to go in between. At the moment it skips each 8-9th number.

The final work I wanted to do was have the clock switch off when there is no one in the room. Then quickly speed back up to the correct time when someone enters the room.

Arduino Bots

These are my arduino bots. They are made of pan and tilt servos and LCD screens. They “talk” to each other via their screens. Images or video of these do not show up the text on the LCD screens, so i will have to make a version with subtitles (On my list of things to do). They are basically little robots who are trying to collaborate. They talk about potential ideas, try a few things out, have some discussions and a couple of fights.

LCD

The Monochrome LCDs are 16×2, one is I2C interface the other is a 3 wire interface– this is what i had, so is what i used. more on LCD…

Servo

Their bodies are each made of two servos for the pan and tilt movement. External power is needed if you are connecting multiple servos to your arduino… just make sure you connect the grounds together. On servos: http://www.arduino.cc/playground/ComponentLib/Servo

etc

Using large amounts of text for running a dialogue heavy project like this will use up all your ram and cause a stack overflow. I learnt this a little bit too late in my project and just switched to a mega (the 8KB was enough). but next time I will save text strings to flash(progmem). The uno has 2KB of sram compared to 32KB of progmem.

I would also like to have these bots running from independent arduino and communicating with each other. With my limited experience was slightly too ambitious for this project- but once i get them back I will give it a try and post my results.