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Project:Traffic Lights: Difference between revisions
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→Wiring
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The traffic light is powered from 90-250v AC (50/60Hz). The controller contains an AC-DC convertor to bring it down to the 3.3V required by the ESP8285. The 4 relays output mains voltage, which is then dropped down to ~12v AC by an individual transformer ''per bulb''. | The traffic light is powered from 90-250v AC (50/60Hz). The controller contains an AC-DC convertor to bring it down to the 3.3V required by the ESP8285. The 4 relays output mains voltage, which is then dropped down to ~12v AC by an individual transformer ''per bulb''. | ||
It was suspected that the transformers were generating Electromagnetic Interference (EMI) when switching on and off, so an off the shelf snubber has been put in parallel with each. A commercial filtered IEC socket has also been added. Since these modifications no further EMI problems have been reported. | |||
====Lamp to GPIO mapping==== | ====Lamp to GPIO mapping==== | ||
