I have built some nifty occupancy detectors with IR sensors that basically fit under a piece of fastrack - it’s a relatively simple pcb, has two IR sensors, and sensitivity pot, and a esp8266 chip that sends occupancy data over wifi via MQTT. (I have a software dev/industrial IoT background). Currently this is all powered by a separate 3v dc buss. My question is since I have 18v ac right at the fastrack - is there a good safe and *compact* way I could just take power from the track and have everything inside a piece of fastrack? I know there are thing like the Lionel crossing gates that have lower voltage components - but they are not constantly on. I worry most about heat and of course building a board that is small enough to fit under the track. It’s not a huge deal to have a separate power source, but it would be good to have all this capability I built available in adhoc setups too and not having to run separate power. Compact and dealing with any heat seem to be my challenges.