Saturday, January 25, 2014

Back in Action with Beagle Bone Black Experiments

Hey Folks, I have been away a long time. I once read advice about writing a letter, and the first thing the guy said was 'never start by apologizing for not writing'. So, no apologies for not writing. Instead, thanks for stopping by.

As we may or may not know, I am active with Bloomington, IN's hackerspace, Bloominglabs. I handle the social media and promotional stuff and am on the board. Sometimes I even hack or make things.

Recently we started a hackable thermostat project. We got the 'minimally viable' bit up and running, so for example if we have a meeting at 7, I remotely kick the heat on at 6. Also I can see what the temperature is remotely.

We experienced some heartache recently, however, when it got below zero and we forgot to think about the fact that the laser cutter has an exhaust running directly outside, letting the cold air into the laser cutter, far from the temperature sensor I installed, freezing the water used to cool it, breaking the tube. As LaserDan put it, we learned nothing from the destruction of the first Death Star.

So anyhow, back to the thermostat. Right now it's an Arduino with an Ethernet shield. We ran the cable across the space, so it's pretty awkward. Also the Arduino has pretty limited power, so we decided we are going to run things on the Beagle Bone Black.

So far, so good. I have various sensors running in my house including temperature. I tried using the DHT22, however the code I found SUUUUUUCCCKKKKKKEEEDDDD, the reason being the timing was way off. On our friendly Arduino, we can be assured, especially if we turn off interrupts (as is done in the handy library from the adafruit people) that our program is the only one running. On the BeagleBoneBlack with Ubuntu, no such luck. Some people claimed to get it to work, but nobody was happy with it. I got it to give me readings, but with more errors than good readings.

Now I could have gone down this rabbit hole forever, but as luck had it I also had a ds18b20 with the one wire protocol. This was (relatively) easy to set up, and way more reliable, as detailed here. Sometimes you just have to let go and move on.

I'll try to post more frequently on here about my experiments, Beagle Bone Black and otherwise, especially about things I get stuck on and then solve. Hopefully somebody else will benefit. But if life takes me elsewhere and I don't post as much, well, no regrets and I'm not sorry.

(I think I've covered myself from the sad 'HEY I'LL POST A BUNCH MORE' blog that hasn't had a new post for 10 years now.)

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