ESP8266 current / power usage charts

After a first test with a 4.7 kΩ resistor it was time to connect the INA219 to the ESP8266 + DS18B20 setup I wrote about some time ago. But first I extended the VB.Net app so that I could do the following with it:

  • Set a trigger value so that the app will start collecting the samples after the measured current rises above that trigger value;
  • Set the INA219 Calibration mode from the app, not hard-coded in the Python script running on the RPi;
  • Tooltips for the data points on the chart;
  • Leave a comment in a textbox and a ‘screenshot’ button to save the whole form as .jpg file;
  • Automatic Y-Axis scaling, automatic re-sampling, automatic screenshots (yeah, I love automation…)

I finished most items last Tuesday so now I’m ready to start charting the ESP8266 power usage 🙂

The setup is the same as in the post I mentioned above and I changed the code so that it would mimic Harald Kleins code as much as possible (DHT22 became DS18B20 and MQTT was added) so that we could compare our measurements: Haralds measurements were done with a digital scope + uCurrent Gold and mine with the INA219 (duh). Here’s my current chart (click the image for a larger version with a bigger chart area)  and Haralds version:

INA219 sample of ESP-8266 + DS18B20

What do we see here? A detailed analysis of what’s going on inside the ESP8266 in terms of current draw. The chart is in fact a detailed ‘power map’ cause by calculating the area (mA * milliseconds) between the blue line and the X-Axis we know the power usage for a single sample. With the sample interval, deep sleep current and the power the battery can deliver it should be possible to make a good estimate of what can be expected in terms of battery life. To be continued…

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2 Responses to ESP8266 current / power usage charts

  1. Stephen says:

    So how are the battery life calculations going? Any update to this post?

    Thanks!

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