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Mon 2017.05.15
"It'll be my first IoT board purchase, i'm new to all that."
It is good that you are asking the right questions and I'm sure you will be excited making the correct IoT choice. Supporting @Gordon with an Espruino brand IoT board purchase would be appreciated.
"and could operate on something for months on a 2000mAh cell"
You are correct @Thinkscape under certain conditions. I believe it was @Gordon that covered this in a post I am still trying to locate. I'll do my best to summarize until that link is found.
The idea is to run the device on a 1% duty cycle running at the 20ua drain 99% of the time. These devices consume around 50ma to wake up, 100ma at impulse for mild number crunching, 200ma during warp drive, and up to 500+ma using WiFi etc. The GPIO pins can source around 25ma but the total chip source is only around 100ma for all IO out meaning around five LEDs at 20ma each. As one can see, during excessive WiFi use, an external (wall-wort) power source is recommended to save on battery draw.
Still seeking that link,
RobinESP8266 - NodeMCU - led and ds1820 temperature example
http://www.espruino.com/Wireless+Temperature+Sensor
http://www.espruino.com/Tutorials
EDIT Mon 2017.05.15
Still searching for that post but did find the following:
@allObjects posted the chip GPIO data:
'maximum current from the espruino pins'
http://forum.espruino.com/conversations/280779/#comment12746768See p.59:
http://www.espruino.com/datasheets/STM32F401xD.pdf- Each GPIO pin can source or sink only 25ma
- Total max all pins is 120ma
- Each GPIO pin can source or sink only 25ma
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Robin
Thanks for the explanation.
It'll be my first IoT board purchase, i'm new to all that.
As a side question, you've mentioned 500mA being too little to power it. I was under the impression that the SoC and Wifi would be much less power-hungry and could operate on something for months on a 2000mAh cell - my use case will be a temperature sensor: thermistor + resistor + Erduino WiFi, probing the temperature every 60s, posting a handful of small packets via HTTP via WiFi.
What is your experience with ESP8266 and power draw?