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The Internet of Things is eating everything alive, and the world wants to know: how do you make a small, battery-powered, WiFi-enabled microcontroller device? This is a surprisingly difficult problem. WiFi is not optimized for low-power operations. It’s power-hungry, and there’s a lot of overhead. That said, there are microcontrollers out there with WiFi capability, but how do they hold up to running off of a battery for days, or weeks? That’s what [TvE] is exploring in a fantastic multi-part series of posts delving into low-power WiFi microcontrollers.
The idea for these experiments is set up in the first post in the series. Basically, the goal is to measure how long the ESP8266 and ESP32 will run on a battery, using various sleep modes. Both the ESP8266 and ESP32 have deep-sleep modes, a ‘sleep’ mode where the state is preserved, a ‘CPU only’ mode that turns the RF off, and various measures for sending and receiving a packet.
The takeaway from these experiments is that a battery-powered ESP8266 can’t be used for more than a week without a seriously beefy battery or a solar panel.
Power consumption and battery life remain limitations for IoT applications. How can they be overcome?
(Score: 5, Interesting) by coolgopher on Tuesday December 18 2018, @12:24AM
Haven't read the article(s), but if they're only getting a week out of it, they're doing it wrong. At $work we're using the ESP8266 for one of our products, and on a standard (good quality) 18650 battery we get a year, sampling every 30sec, uploading once an hour or so. If we upload less frequently, we can easily extend it a year and a half, at which point the self-discharge of the battery is becoming quite significant in its own right. This is on a combination of pure C and NodeMCU [github.com] for the higher-level logic (which only gets booted when we need WiFi).
If you're on battery, you have to approach the solution with that constraint as the first and foremost. The what-appears-to-be-typical attitude of glue-high-level-components-together-until-it-kinda-works doesn't fly in this space. Not if you want things to not run out of juice in a hurry.