1
\$\begingroup\$

I am making a wireless doorbell that uses ESP8266 microcontrollers. To save power, I am considering two possible approaches:

  1. Use normal wifi, but put the modules in modem-sleep, where the processor continues to run but the radio goes into a low-power state. Every 200ms or so (depending on router settings), the router will send a DTIM beacon which wakes the ESP8266 radio up. The ESP8266 will then receive any packets the router sends it, before switching its radio off again. (Admittedly I'm a little unclear on how exactly the ESP8266 can receive a DTIM beacon when its radio is switched off. That would seem to be a catch-22. If someone can explain this, please do.)

  2. Use ESP-NOW, which is a point-to-point wifi protocol that doesn't involve any routers or IP addresses. However there are also no DTIM beacons, and so the ESP8266s will need to avoid any form of sleep, lest they miss messages. I get the general impression that ESP-NOW may be less power-hungry than full TCP/IP wifi though.

So basically my questions are:

  1. Which method consumes less overall power, given that option 1 can use modem-sleep and option 2 cannot (at least, the receivers can't)?

  2. Are there other reasons to choose one solution over the other?

  3. Does ESP-NOW really consume less power than standard TCP/IP wifi (assuming sleep is not used in either case)? How much less? And why?

  4. If the sending ESP8266 were to use modem-sleep or light-sleep, how quickly could it wake up from either of these states and transmit an ESP-NOW packet when the bell is pressed?

\$\endgroup\$
4
  • 1
    \$\begingroup\$ For TCP/IP, the scan of network searching for SSID to setup WiFI would take up to at least 6 seconds, plus establishing a TCP/IP connection, the overall awake time would probably at 6-8 seconds. While a round trip of ESP-NOW took around 100mS. My ESP-NOW doorbell has an ESP-01 with a LDO that consumed together of about 25uA running at 80MHz. With a 1000mAh battery, it estimated last for 1204 days (i.e.> 3 years), and with a 2900mAh battery would last for 3373 days! (> 9 years!). My ESP-Now transmitter is in deepsleep mode, and the receiver is always on. \$\endgroup\$ Commented Jul 21 at 7:57
  • \$\begingroup\$ You can read about my ESP-NOW doorbell project which provides more implementation details. \$\endgroup\$ Commented Jul 21 at 7:59
  • \$\begingroup\$ But how much power does your receiver consume, given that it cannot sleep? \$\endgroup\$ Commented Jul 21 at 13:32
  • \$\begingroup\$ For receiver running at 80MHz (you don't need running it at 160MHz), it is around 20-30mA with WiFi on, which is why it needs to be powered. During the short burst of receiving data the current is about 80mA for about 100+ milli-seconds. \$\endgroup\$ Commented Jul 22 at 2:04

0

Reset to default

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.