ESP32 CoinCell is a Tiny, Coin Cell Powered ESP32 Pico D4 Board

ESP32 boards can easily be powered by batteries, either through an external USB battery shield, or direct connection to an ESP32 board fitted with battery charger circuitry. But Miek Rankin has done something a bit different, as he designed ESP32 Coincell board based on an ESP32 Pico D4 SiP (System-in-Package) powered by a rechargeable LIR2450 coin cell battery with 100mAh capacity.

ESP32 CoinCell

ESP32 CoinCell board specifications:

  • SiP – Espressif Systems ESP32 Pico D4 Wifi/Bluetooth processor
  • Connectivity
    • 802.11 b/g/n WiFi up to 150 Mbps
    • Bluetooth 4.1 LE
    • On-board antenna
  • Display – 0.69″ OLED display with 96×16 resolution
  • USB – 1x micro USB port for charging and debugging (via CP2102N USB to TTL chip)
  • Sensor – LIS3DHTR accelerometer
  • Battery / Power Supply
    • SE5218ALG-LF 500mA LDO power supply
    • SL4054ST25P LiPo battery charger
    • Socket for  for LIR2450 (3.7V/100Mah battery)
    • Consumption – 0.45mA in sleep mode
  • Dimensions – Small

ESP32 Coin Cell Battery

If you don’t connect the battery, the board can still be powered through the USB port. No battery life was provided, but let’s say if you kept the board in sleep mode, a 100mAh battery should last over 200 hours @ 0.45mA, or a bit over 9 days.

The project is somewhat open source hardware with PDF schematics, Gerber files, and Arduino sample code available on Github. Mike showcases the board and sample firmware in the short video below.

Mike explains the board “was not made for any specific purpose and was a design challenge to try and made it as small as possible”, so it may never be sold directly. You can also make it yourself if you are interested, or contact Mike via his Github page if you have a specific use for the board..

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Brian
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Brian

non-rechargables tend to have double the energy density of rechargables, so using a cr2032 instead (235mah) should do nearly 3 weeks.

Philipp
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Philipp

But a waste of resources, if you do not use rechargable ones. Every month replacing the battery… So, I would use a rechargable one. But I think the ESP32 just takes too much energy for running on a button cell.

Member

I don’t know about you, but with a few additional tweaks, this becomes something interesting in the manner of, “purpose,” and one could maybe see it being made.

Mario
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Mario

Looks pretty neat, but I don’t see any GPIO (to be fair, I didn’t listen to the video). With some GPIO, I can imagine using this on a gaunlet to control a robotic arm, or something like that!

DurandA
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> 100mAh battery should last over 200 hours @ 45mA

How did you calculate this estimation?