Reddit mentions of SUNKEE DS18B20 Temperature Sensor - Waterproof Digital Thermal Probe Sensor DS18B20DS18B20 Temperature Sensor - Waterproof Digital Thermal Probe Sensor DS18B20

M:Thanks guys, I wasn't sure if I was bothering the wrong people with this junk. So did you know there is like one model of peltier that is freaking cheap, and everywhere, and everything else is crazy specialized and expensive beyond reason? The TEC1-12706, you can get 10 of them for 17.50 on ebay, but I actually found a 3 layer one that runs off 3.3v, 0.5a, about half the amperage a raspberry pi can output and the same voltage, the stupid little thing costs, I kid you not, $137 USD. If I commit to this project, I think I am going to buy a peltier, dissect the first one, and see if I can cut the thing in quarters. One that runs off 12V/6A, might be fine if I cut it in quarters and try to run each quarter at 3.3V/0.26MA. Amperage will only be at a quarter of projected safe capacity, but it will be a little over voltage. So a Raspberry Pi 2 might be able to run this thing.

Right, the thing, I want to make a working geth arm. I have a friend with a 3d printer that can make hard parts for me if I buy the plastic. I would need some of these, http://www.ebay.com/itm/5x-TEC1-12706-Thermoelectric-Cooler-Heat-Sink-Cooling-Peltier-Plate-Module-6A-US-/281688835346?hash=item4195f68512:g:99sAAOSwpDdVUF4R

Model: TEC1-12706
Size: 40mm x 40mm x 4mm
Operates from 0~15.2V DC and 0~6A
Operates Temperature: -30℃ to 70℃

You know what, screw cutting them down, I should just shoot for 40mm as target muscle width.... I should make this it's own thread, shouldn't I?...
Once I export some game models and build the frame in sketchup.... which is going to happen after homework.

So, the muscle, coiled up fishing line becomes a linear actuator when heat is applied. Run a bunch of them parallel to each other and attatch a heater/cooler (peltier) and suddenly you have a high power linear actuator.

I want to insulate it with mylar, which you can get a large blanket of for like 5 bucks. I would need to enclose it in a flexable pouch though, something that could hold a low viscosity oil, to both lubricate and spread heat faster.... actually, a mixture of cooking oil and toothpaste should be fine. You can use no grit tooth paste as thermal grease for your CPU by the way, but it is recommended you thin it down a little first with 25% petrolium jelly.... I want it to be a lubricant too, so I would probabaly go 50%. Both of these can be found at dollar stores.

You would need one of these if you wanted to report the tempurature back to the Raspberry Pi, from which you could gather the muscle's position.
http://www.amazon.com/365buying-DS18B20-Temperature-Sensor-Waterproof/dp/B008HODWBU/ref=sr_1_1?ie=UTF8&qid=1453260689&sr=8-1&keywords=raspberry+pi+temp+sensor

All of the parts I have found so far that I need can be gotten on a pretty cheap budget except for the flexable hoursing.... Scratch that, bicycle inner tube, clamped at either end using a radial screw clamp, also dirt cheap. It won't be as pretty, but it will be easy and cheap.

That leaves the mechanical arm design, I should just go rip one off thingiverse and slap exported geth models onto it.

I need to do something that isn't this for a while now.

Here is the finished product:
https://www.dropbox.com/s/42gitcg9l4986mb/Screenshot%202014-09-30%2018.25.07.png?dl=0

Here is some open source libraries and parts I used:
https://github.com/Mikhus/canv-gauge

http://www.chartjs.org/docs/#line-chart-introduction

http://socket.io/

http://nodejs.org/

http://amzn.com/B008HODWBU

http://amzn.com/B00FJNGH8M

Parts List - There is a decent list in brewpi docs as well but I will list what I bought below as well. BrewPi Doc's Build Planning

What I purchased:


Arduni Uno - RevC

RaspPi Model B

4GB SD Card
and SD Card Reader

2 Solid State Relays

LCD Module

BrewPi Arduino Shield You can buy this assembled for 10 more Euros. I chose to solder it myself.

2 DS18B20 Single Line Temp Sensors

Some kind of case to hold it all. BrewPi makes their own but I chose to hack up a cash box for all the electronics.

This does not include the things needed for the chamber (cooling and heating elements), the rectangular wall socket to hook up to the relays, wiring, etc. Amazon also may not be the lowest price for everything either so shop around.

I did one with a Rpi, Arduino, and http://www.amazon.com/gp/product/B008HODWBU?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00 . Worked. But it was so much more complicated than an off the shelf wireless thermometer and the added utility wasn't enough to justify the complexity.

I've got several on the way for me to use, and have read pretty much all the literature related to them.

Yes, the DHTxx sensors look like good products, assuming you don't need to check the temperature ridiculously often, and you don't need very many sensors (each sensor will use one GPIO pin, besides the power and ground.)

Note that you need a pull-up resistor to make them work, (most digital temp sensors will require one) and some of them don't include that, while some do, just have to look around, and make sure it includes one, or make sure you've got a couple on hand.

Personally, I wish I had known about the DS18B20 that /u/mightyfaggot mentioned, because those use a true 1-wire interface, thus allowing you to have hundreds of them, while only using one GPIO pin, and you can find them pretty cheap... $2.78 WITH shipping! Do note, however, that these are just temperature, while the DHTxx sensors also do humidity.

You could do this, but I prefer to use a digital sensor that's already 'waterproof' and is also widely supported on the Arduino, the DS18B20.

• Amazon
  
  
• Aliexpresss

I'm currently looking into setting up my rpi2 as doing something similar. Just ordered this with a python. Also what's ORP? I know pH probes are expensive, but what pH and TDS probes are you using?