Friday, November 22, 2013
Circuit Board Finished and Working
Milwaukee Makerspace today and finished my hand soldered circuit board to detect water for the Home Environmental Sensor Array. I started it last week but only got about halfway done. Today, I soldered the second half of the detection circuit, and added two screw terminals.
One pin on the first screw terminal connects to a pin that constantly puts out 5v of power on the raspberry pi. The other terminal goes to a ground pin. That terminal will be used to power the fan on the power supply box.
The other screw terminal connects to pins 7 and 9 on the rapsberry pi. Pin 7 will output 3v of power to turn on the PowerSwitch Tail. Pin 9 is ground.
It probably took about three hours to get everything soldered. I took my time testing each connection and looking for shorts with the multimeter to make sure I did not do anything wrong.
I plugged the Raspberry pi's ribbon cable to the pin headers on the breadboard and fired up my HESA program. It worked perfectly (more-or-less). The fan spins, the PowerSwitch tail has power, the program alternately sends power out one of the four circuits, and it detects power coming back in when a circuit is closed. The only thing that did not work is that it did not detect current when using water from the Makerspace tap. However, that did not work last time I tried it but the circuit did work with New Berlin water from my well. So, I'm hopeful that the circuit will work at home as well. If not, or if I want something more reliable, I can replace the test leads with a float that closes the circuit when the water gets too high.
Next step: Build an enclosure.