EasyEDA schematics
Fritzing diagram
Powered by a 18650 battery with the capacity of 3300mAh.
| State | Consumption | Period |
|---|---|---|
| Wake - with onboard LEDs ON | 100mA | ~1s |
| Sleep - with onboard LEDs ON | 30mA | ~1s |
| Wake - with onboard LEDs OFF | 160mA | ~5s |
| Deep Sleep - with onboard LEDs OFF | 4mA | ~15 min |
Over an hour period we expect to have 4 times 5s spent on reporting. During these intervals the energy consumption is 160mA.
In the remaining time we expect to consume 4mA. This period lasts for 3600s - (4 * 5s)) = 3580s.
The total battery consumption over an hour is around 160mA * 5s * 4 for the reporting periods, and 4mA * 3580s for the deep sleep.
Consumption over an hour is (3200mA + 14320mA) / 3600s ~= 4.86mA
On average expected reporting time should be 28 days (3300mAh / ~4.86mA / 24h)!
- Current reporting time without deep sleep and both LEDs blinking ~22 hrs
- Last reporting time with deep sleep ~3 days (on balcony, but suspecting continuous connection problems. See issue #12)
- Last reporting time with deep sleep ~14 days (on balcony with a step-up converter)
In order to reduce power consumption Node MCU requires hardware modifications. This is mainly due to the fact, that the CP2102 UART bridge is getting powered even if we use the 3V3 pin. The estimated power consumption is around ~15mA. This can be done with an exacto knife.
Programming and flashing firmware for the ESP8266 can be done with an FTDI chip (see Fritzing diagram)
First we scrape off the resin from the surface to reveal the ciruit.
Next we break the connection.
Another improvement we can do is to include an external antenna. You can solder it directly, or use an U.FL connector for nicer look & feel.
If you want to solder in an U.FL socket, you need to arrange it the following way. Start with cutting off the connection for the onbard antenna.
Arrange the U.FL socket the following way:
For the direct wire connection you can secure your work usgin hot glue. See the images below:
More about this topic is available on YouTube and on other sites, here and here.
Measurements made using an oscilloscope through a shunt resistor of 1 Ohm. See the setup below:
Wake - with onboard LEDs ON shows 60mA usage on average.
Deep sleep with periodic wake times - shows 17mA usage on average with 80mA peak. See the table above with estimated battery life.
Deep sleep after hardware modifications - shows 4mA usage on average with 160mA peak. See the table above with estimated battery life.
- https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/
- https://randomnerdtutorials.com/esp8266-bme280-arduino-ide/
- https://arduinomodules.info/ky-015-temperature-humidity-sensor-module/
- https://nothans.com/thingspeak-tutorials/esp8266/building-the-internet-of-things-with-the-esp8266-wi-fi-module-and-thingspeak
- https://github.com/nothans/thingspeak-esp-examples/blob/master/examples/RSSI_to_ThingSpeak.ino
- https://www.thingiverse.com/thing:144665
- https://www.thingiverse.com/thing:4805867
- https://www.thingiverse.com/thing:1718334
- https://www.thingiverse.com/thing:1985125
- https://hackaday.io/project/167731-testing-cheap-linear-li-ion-chargers-for-solar
- https://forum.arduino.cc/t/how-to-power-esp8266-ch304-with-18650-li-ion-battery/1179338/14
- https://randomnerdtutorials.com/esp8266-voltage-regulator-lipo-and-li-ion-batteries/
- https://randomnerdtutorials.com/power-esp32-esp8266-solar-panels-battery-level-monitoring/
- https://www.youtube.com/watch?v=f2yMs-JAyQM
- https://www.youtube.com/watch?v=ttyKZnVzic4
- https://youtu.be/6DY767kQnUM?si=SXygTiLH4zx0RgAH