Difference between revisions of "Project:Traffic Lights"

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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''.
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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====

Revision as of 17:52, 16 March 2019