| So it's built and calibrated/tested. Just got to photoshop a meter scale and print a few labels for the switches and leds.
Meter scale is -25 to +25 degC. Push buttons are set-point and alarm-point. Toggle switch is alarm mute. Red leds are alarm and mute(flashing). Green leds are Power Request, Request Acknowledge, and Power Available. The 2 RJ connectors are one for the LM335 temp sensor and one to connect to the control box which turns on and off the UPS.
The control box will have a number of inputs, 2 of these boxes (fridge & freezer), as well as manual buttons for the microwave and washing machine and anything else. The control box has interlocks so you can't run everything at once.
The UPS is an APC 1600 watt pure sine wave. These have manual buttons for start and stop. The control box will switch a relay across the start & stop switches, so we have power-on-demand. Each power circuit also has a solid-state relay so the 240 volts is only fed to where it's supposed to go.
Main components are the LM335 temp sensor, an LM324 quad op-amp, a TL431 voltage reference, and a pair of BC547 to drive the alarm led/buzzer, and an open-collector feed to the control box. I had t run flying leads to the RJ connectors because it's only a single-sided board.
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