The greenhouse controller project


HPIM5289So one problem I had last year during the summer was during vacation there was no one to water the plants in the greenhouse for about a week and a half. That week also happened to be extremely warm and so it cooked all the plants inside and ruined most of the harvest. Not wanting the repeat that this year I dusted off my old Microchip ICD 2 device, pulled out my prototype boards, cleaned off my desk to give myself a work space and started putting together the pieces to have a internet enabled greenhouse controller.

HPIM5290I happened to have a PIC microcontroller and so I started working on a controller that would be able to water the plants is they get too dry, or vent out the greenhouse if it gets too warm and report the temperature, moisture and more through an Ethernet connection. One requirement that I have is that the controller needs to run off of solar energy and those panels can get voltage ranges that are over the limit for PIC microchips and especially for the PIC18LF14K22 microcontroller that I was using for the project. The solution was a large input voltage range step down voltage regulator that could take up to 60 VDC and step it down to 3.3VDC, which is what the microcontroller was expecting. This part is the middle left of the board with the giant capacitor.

HPIM5291So here is a picture where you can see the PIC in the middle, the Ethernet controller (right side) and the voltage regulator (bottom). Since the Microchip ICD 2 has too high a voltage on the Vpp supply to the chip and would damage the chip, I still need to put a voltage limiter on that output before hooking up any more of the wires.

As I continue to work on this project I’ll be posting more and more about the controller and the results of my testing. If you have any suggestions on what might be a good idea to add, please leave a comment below.

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