Building my automatic coop door opener. Wifi, Open source, ~$60

[detz]

 

[Toddrick]

I've decided to buy a Raspberry Pi 2 and a big sensor kit to play around with a bit of everything. I don't have a specific project in mind since I already ordered a coop door.

So I still have one question about using a 12v motor, which seems like would be the minimum required to power anything other than a toy. I believe the Pi only outputs 5v, plus it must be shielded from the motor by a special GPIO controller right? Which one did you go with? I see tons for the Arduino, but not for Pi.

 

[tcstoehr]

I've decided to buy a Raspberry Pi 2 and a big sensor kit to play around with a bit of everything. I don't have a specific project in mind since I already ordered a coop door.

So I still have one question about using a 12v motor, which seems like would be the minimum required to power anything other than a toy. I believe the Pi only outputs 5v, plus it must be shielded from the motor by a special GPIO controller right? Which one did you go with? I see tons for the Arduino, but not for Pi.

You surely don't want to power the motor from an Arduino or Raspberry Pi GPIO pin, even if you had a 5V motor. The amp draw is too much. Instead you'll need to use your GPIO pin merely as a way of sending a control signal to a transistor or a relay or motor controller, or some device capable of handling higher current loads to the motor. Other than that I don't know anything useful. As I recall YouTube is full of tutorials on this sort of stuff. Even if they're Arduino tutorials it should be easily adaptable to the Raspberry Pi environment.
BTW the Ador1 commercially available auto-chicken-door motor operates fine on 5 volts, optimal at 6-7.

 

[Toddrick]

Okay, I think I understand well enough to do some tinkering. I could have a 6v motor connected to a battery with a transistor in between that is controlled by the GPIO, or I can use one of those GPIO controller boards to do the same thing, except without me having to worry so much about the wiring.

 

[gpop1]

if you are uncomfortable with electronic side just use a pre made shield and a double relay. If you understand electronics then a mosfet H bridge is the way to go. (I prefer the double relay as theres no was that you should be able cause a short)

 

[detz]

Yeah, the other two posts are right. You can not drive the motor from the PI (or an Arduino) because they were not build to support the level of current a motor draws. There are a bunch of options depending on your goal but the easiest (not cheapest) is to get an h-bridge circuit which will work with any micro-controller/computer. Something like:

https://www.sparkfun.com/products/9670

I used a simple h-bridge ic in my build, same thing without the fancy stuff and much cheaper as you can see.

https://www.sparkfun.com/products/315

You provide a higher voltage/current source to that chip and then control it using something else that way to the two power sources don't touch.

 

[detz]

Update:

Door opens and closes daily so I'm confident the code is right. I've add three new sensors, two temperature/humidity sensors and one water proof temperature sensor. With these I'll be able to tell the temperature/humidity in and outside the coop as well as my water temperature for the winter.

 

[gpop1]

im interested in trying the rassberry especially as I want to go touch screen on my next project. What program are you using to write and edit the text in.

 

[Toddrick]

I'm probably getting this kit. It doesn't have the sensors I want, but it has all the other miscellaneous stuff. Do you buy your sensors individually or is there a sensor kit that you recommend?

http://www.amazon.com/gp/aw/d/B00P2E9W30/ref=ox_sc_saved_image_1?ie=UTF8&psc=1&smid=ADHH624DX2Q66

 

[gpop1]

I'm probably getting this kit. It doesn't have the sensors I want, but it has all the other miscellaneous stuff. Do you buy your sensors individually or is there a sensor kit that you recommend?

http://www.amazon.com/gp/aw/d/B00P2E9W30/ref=ox_sc_saved_image_1?ie=UTF8&psc=1&smid=ADHH624DX2Q66

Its more about getting your hands on some parts and some lessons in how to use the parts that count. Once you get that far then you come up with a project and order what parts you think you will need. There are free books online in pdf format which will help you in the beginning. The kit you are looking at includes lessons to follow using the parts in the kit.