Tuesday, December 27, 2016

Upgrading the sensor pods: Boxing the boards.

Now that I've confirmed that the CAI board works, it's time to put it in a box. For this project, I used one of the boxes I'd originally purchased for the energy monitor project.

This was a wired alarm housing when purchased, although I discarded the alarm board after removing some of the more interesting parts, like nice screw-terminal connectors. (They have the same footprint as the ones I used on the purple alarm relay board.) I didn't need the built-in board, and most alarm manufacturers won't talk to you unless you have a license. Into the recycle bin it goes.

I've made some minor modification to the box, which includes drilling some new holes inside (the original push-lock standoffs were kept and re-used) and putting a meter on the front. Since this box will be talking to the leak detector box, I decided to add the meter to this one. As this will sit on the wall as you open the closet door, you can immediately see the meter without peering around the corner. It's currently displaying 13.5, which is being provided by a power supply.

Inside is still pretty sparse. I've placed the terminal strip for the incoming power, mounted the CAI board, and wired it and the meter in place and tied everything down. There will be another board under the terminal strip, probably a rectifier and supply board as I'd like to add a current monitor to the unit, but I'm not sure. Since I'm keeping the same form factor for everything, I went ahead and punched the pilots for possible mounts.

The CAI board is connected to the local network via a wireless adapter, aka a repurposed WRT54GL, that will probably follow it into the closet. Both units are perfectly happy running at 13.6V, so no other regulator is needed save the battery. (From what I can tell, the WRT54GL is good up to about 18V or so, and is probably good to around 10V on the other end. I have not verified this, so YMMV.)

Something I've read in a few places is these boards like to lock up after a few days when running with multiple DS1820s. I've placed a solderless breadboard in the bottom for now with 4 sensors on it to see what happens. So far, nothing other than good solid temps. As the CAI board is capable of reading I2C units, I also have a BMP280 pressure sensor mounted, although this isn't hooked up as of yet. That, and possibly an I2C RTC board are projects for another day.