ESP8266 Community Forum

SO, you are telleing us all the remote sensors are in the same location and are woken up by a timer?
If so, why are you not collecting the data from each sensor on one ESP by use of a multiplexer?

So a couple of things:
- the timer on the ESP is not very accurate. The devices will not all wake up at exactly the same time so you have no problems there. Even a delay of 200ms will be enough to separate them
- you can manually set the Wifi channel so no need for a scan
- you could also set the IP address manually, or have the server assign an address the first time a client registers, which means you avoid DHCP
- you could set up the server to wait for connections on UDP or even TCP and receive data. With a limit of 5 concurrent connections you would still get all the data received from 50 units within a few seconds
- if the client happens to be refused, you could retry or store and send the next period

Waking and sleeping every 90 seconds and using the transmitter every time just to send 10-15 bytes is going to be pretty power hungry. You would be better to wake and take the measurement, then save it and sleep again, and then send the grouped data every hour or so if that's possible. Does the data need to be received in real time or just taken in real time?

AcmeUK wrote:SO, you are telleing us all the remote sensors are in the same location and are woken up by a timer?
If so, why are you not collecting the data from each sensor on one ESP by use of a multiplexer?

Exactly that. An analog multiplexer or a shared (digital) bus.