Constantin
Well-known member
So here is the PCB for the latest iteration. It uses 16A relays because the ultrasonic emitter vendor claims the unit may use up to 300W of power. One relay is for the emitter, the other for the water solenoid. The latter definitely does not need a 16A relay, it was simply convenient to use two of the same.
Here is the underside.
You may notice the ACS711 current sensor that tells me if the emitter is running or if the water levels are too low for the emitter to come on. Big diodes deal with any inductor-related currents coming from the relays. As always, a LTV844 keeps the higher voltage signals from the AC system very separate from the Teensy LC running the show. Small full wave bridge rectifiers and a cap on each channel hence provide the Teensy with a very clean on/off signal for each of the four zones that may be calling for humidity.
On the topside,
there is a header for Pauls touchscreen which will simply scroll text regarding current operating conditions. A three pin header handles a small 15 LED WS2812B strip that I will put int the duct. Whenever the unit is running, the duct will hence light up red, illuminating it. That helps identify issues such as wall condensation and it provides a visual cue from above that the humidifier is running.
As for safety, I still use a fully independent humidity controller to shut everything down in case the house fan is not running. The teensy also still controls a powerswitchtail that controls power to the ultrasonic and fan system.
The boards should be here soon, Digikey already delivered the components. Can't wait to reflow it all. The code compiles... but will it work? Future iterations may make use of Pauls touchscreen function. For now, it's simply a great passive way to show what the Teensy is doing without having to attach a CPU to make it happen.
Here is the underside.
You may notice the ACS711 current sensor that tells me if the emitter is running or if the water levels are too low for the emitter to come on. Big diodes deal with any inductor-related currents coming from the relays. As always, a LTV844 keeps the higher voltage signals from the AC system very separate from the Teensy LC running the show. Small full wave bridge rectifiers and a cap on each channel hence provide the Teensy with a very clean on/off signal for each of the four zones that may be calling for humidity.
On the topside,
there is a header for Pauls touchscreen which will simply scroll text regarding current operating conditions. A three pin header handles a small 15 LED WS2812B strip that I will put int the duct. Whenever the unit is running, the duct will hence light up red, illuminating it. That helps identify issues such as wall condensation and it provides a visual cue from above that the humidifier is running.
As for safety, I still use a fully independent humidity controller to shut everything down in case the house fan is not running. The teensy also still controls a powerswitchtail that controls power to the ultrasonic and fan system.
The boards should be here soon, Digikey already delivered the components. Can't wait to reflow it all. The code compiles... but will it work? Future iterations may make use of Pauls touchscreen function. For now, it's simply a great passive way to show what the Teensy is doing without having to attach a CPU to make it happen.
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