Right now I'm looking to create smart blinds. The motors don't use that much power, but the issue is the MCU listening for commands. The ESP32 support BLE, but it's power consumption is still rather high, so batteries would only last a few days at most.
Even at once every 10 minutes, it should manage almost 3 weeks without requiring a recharge.
Some options that definitely help is to quicken the Wifi reconnect. ESPHome has options to disable AP scanning and doing a fast-and-dirty connect&send. Using MQTT also helped a lot compared to using HTTP.
The most important part is to reduce the on-time as much as possible. 30 seconds is still way above the lower limit that I can do. If you halve it you can double the amount of data points without additional energy by reducing the sleep time.
I'm working on replacing the battery with a solar panel and supercap to power it from ambient shadow light entirely, the numbers to agree that it is possible in my case. Would help to keep it alive in cold weather.
After a few months it stopped working, I think some moisture got in and the DHT11 failed.
A bare chip makes it much easier, and you need to balance what comes online and how long it sleeps to still work in your use case.
It's not all that easy in some cases, but it can be done. I've used [1] as a resource before in my own projects.
[1] https://github.com/z2amiller/sensorboard/blob/master/PowerSa...
Biggest problem we found was enterprise networks would randomly kick you off if you were using DHCP. I think because they would assume that if you hadn't transmitted in five to ten minutes it meant you'd gone away. Using static IP fixed that.
Edit: Friend of mine that mucks with ESP8266's uses the low power timer to reset and wake the device up out of deep sleep. (Via a simple hack I think just connecting a timer pin to the reset).
Star-mesh topology, with batteries on the leaf nodes. Solar further in. Excerpt: "I’m expecting about 3 months at a 5min log interval using a 2000mAh lipo battery."
on Banggood they show that they sold 242338 of them:
https://www.banggood.com/SONOFF-Basic-10A-2200W-WIFI-Wireles...
on Amazon the 4 pack listing has 548 customer reviews and there are other listings with hundreds of reviews and probably lot more people bought it than the reviews.
https://www.amazon.com/Sonoff-Remote-Control-Compatible-Andr...
It's used mostly for lights, fan, AC, heating, so not that much critical, but still lot of devices.
There are way, way more moneyed companies in the wifi MCU game, but I have not seen a single competitor chip outside sales demos yet.
Redpine had big dotcoms backing, but it seems that even they dropped the ball on them in favour of Chinese chipmakers. Amazon and Google recently reached out for MXCHIP and Espressif, and their Redpine based solutions never went beyond the tech demo stage.
The real advantage of the ESP8266 however is its raw popularity. It has an Arduino environment, tons of ready to run sketches, Basic, Javascript, Lua and Python interpreter environments and lots of interesting projects already done with it.
The ESP32 follows right in its foot steps with even more features, power and power saving features. Espressif really saw the market the DIY community means and did some minor tweaks to its policies to cater to it, which probably helped its popularity with commercial hardware makers as well.
Plus, since it comes from "another China" it's subject to Chinese customs duty which negates whatever cost advantage it could have.
Any recommendations for good, affordable dev boards (say under 20Euro/USD), that are easily available?
(I have been playing with RobotDyn Blue Pills and Rust, but no wireless or Bluetooth connectivity.)
No. Espressif is used because it is _cheap_ and has relatively good support libraries. Just the chips/modules from other vendors are usually 15 to 20€ in single quantities while you can get an ESP8266 minimum development board (almost all normal arduino boards are minimum development boards) for like 3€.
Unless other vendors reach that same level, they will always stay back.
I work with a mid sized engineering consultancy.
We began switching to ESP as our primary platform just around 2 years ago, just as wifi gadgets were starting to boom.
To date, we got 500 megs of MCU project in our repo. Though most of code is repetitive, there is no chance we will part with such a huge codebase.
Being able to complete a $200k project in a few weeks through code reuse, instead of few months is huge, and imagine how it is for bigger companies with own hardware. No chance anybody switching now.
No. It was first comer advantage in affordable wifi MCUs since they existed just fine before but only as more expensive solutions as I mentioned. You can keep on claiming otherwise but the facts don't support you in claiming that there weren't wifi MCUs before.
Technically, and conceptually they were hopelessly behind an integrated WiFi MCU.
Espressif did not innovate in the technology space but in pricing and having enough documentation available that hackers could piece together an open source toolchain and libs for the chip.
These chips are the first hits for searches such as "Arduino wifi module", "breadboard wifi", "IoT wifi module", and many, many more as they're the downright easiest way to add wifi to something that doesn't have it out of the box.
I'm not sure how applicable these attack vectors are in the real world, but they affect a very large number of devices for sure.