The Coop CPU (Computer) and connections

One of the incentives for computerizing the coop
was a chance to use the new single board computers.

I had worked with single board computers in the late 1980s
but the new ones have so much more in the way of I/O and control.

Here is the main computer board and add ons used in controlling the coop.

The Computer board is a Raspberry Pi model B 
Not all of the GPIO pins are available for PIR sensor input but three work fine.
I did not buffer the GPIO pins connected to the PIR sensors.

The GPIO pins are used and are made accessible by the second board
which is a Pi Plate Prototyping board
This board is great for prototyping as one can add buffer ICs and such
My main reason for using it was to make the GPIO readily available
with the screw terminals that come with the Pi Plate kit.
The Pi Plate also connects to the buffered I/O and relays on a Pi Face Digital board, the top board on the stack.
coop cpu interconnect
The ribbon cables from the PiPlate connect to a distribution board which has two more boards with two relays on each board.
The interconnection to the GPIO uses three wire connectors which you can see labeled here with the GPIO pin number.
The three wire connectors supply 5VDC ground and the GPIO. This allows direct connection to the PIR modules
and most other available modules like the temperature and humidity sensor (lower right).
distboard

This brings up a caveat in design.  When purchasing add on relay boards, check the activation voltages.

The fully assembled coop cpu is installed into the cupola on top of the coop roof.
In this image you can see the Camera board for the internal view of the coop,
the router and connections for additional devices and cameras
coop cpu installed
On further pages I will describe the light modules and the code to operate the coop.

written by Doug Wyman

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