Hi. Very happy with the range i get with a temperature senor attached to an Esp8266 using WiFi. I need to ad hoc poll it couple of times a day from my phone, meaning it needs to be always on so battery power in this scenario is out of the question. In order to run it on batteries, I was thinking of putting the Esp to sleep and using a low power wake up receiver say on 433MHz band just for the Esp to do a single measurement then go back to sleep. The 433Mhz receiver would need to be active all the time.
The cheap 433MHz receivers that seem to be used everywhere still draw too much current. I believe 4mA has been reported. A cheap doorbell receiver I have only draws about .3mA however which is useable and I can get about 20 meters out of it which is adequate distance.
Having trouble reverse engineering the doorbell receiver and wondered if there were some good low power 433MHz receiver circuits someone could recommend. Or perhaps another way of doing this. Since the readings need to be on-demand, duty cycling the Esp for an acceptable battery power usage might introduce too much latency.
Thanks