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Cinema Display LED control with 9V-12V ESP8266 Web Switch

I picked up one of the A 4 Cinematic Light Box devices to use as a team sign in an Agile Program Increment planning meeting.  The unit requires 6 AA batteries. That seemed wasteful so I added a 9V barrel jack to it to power it with a 9V wall wart.

The next step in turning a $15 box into a $40 project was to add an ESP8266 relay board to enable WiFi control for the sign light.  My controller is ESP8266 Link Sprite LinkNode R1 that was locally available at Microcenter for $11.

Basic Circuit. The basic idea is to turn the ESP8266 into a 9V switch that needed no external power. I wanted to tap the 9V intended for the display LEDs and drop it to 5V to run the ESP8266 without need of a 2nd power source.

Two diodes tap power from either jack and sends it to the ESP8266 and relay circuits.  It doesn't matter which jack is used as the inbound power source and which as the outbound to the display. Either will work because of the two diodes. They are arranged a way that doesn't limit whi…

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