w3p706

I did exactly this for my finnish anki flashcards. you can see the implementation here: https://github.com/w3p706/anki-gen-fin/blob/main/ankigenfin/...

If you are looking to convert very short texts or words into speach, I had best result with eleven_multilingual_v2 with the following text for tts "Hän sanoo rauhallisesti ja hitaasti: <break time=\"1.0s\" /> '${text}'" An then i use a postprocessing to split at the silence.

This was nessesary as you cannot set the language explicitly and it is detected from the input.

With eleven_turbo_v2_5 you can set the language, but the results are not as good.

I use most the paperwhite 2nd generation (212ppi resolution) as this had good availability and price. but the devices are quite hard to keep apart

the mobileread forum ist full of good information e.g.: https://www.mobileread.com/forums/showthread.php?t=267541

I buy old kindles for this, ~50$ per piece. they have a linux os & battery included. you get in through a serial port and a password generated for your serial number. downside is that you fight the kindle os in certain aspects.

see for example: https://github.com/Neelakurinji123/kindle-weather-display

No, I did not, but I made tests with a configuration that was using more power. I measured total runtime per wakup, and number of wakeups until the battery was depleted. I used this data to estimate the runtime if I take a measurment only every 5 minutes. This does not fully take in account the deepsleep current & battery self discharge. But wake up from deepsleep is definitly working.

From 3.7V to 2.7V I coud activate 37'000 times with a total runtime of about 8h.

Schematic is found here: https://github.com/LilyGO/LILYGO-T-Energy/blob/master/t18_v3...

You also have the battery voltage on IO35 with a 2x100kOhm Voltage divider.

The setup is not perfect, but good enough so far, and practical.

If I start over, i would look into * taking a processor with lower speed und power. * taking CR 123 or a battery optimized for very low self discharge current. * Use a wireless protocol with very low overhead. I use ESP-Now now, WLAN would cut battery life in half.

LILYGO® TTGO T-Energy (http://www.lilygo.cn/prod_view.aspx?TypeId=50033&Id=1170&FId...) is my favorit. It has a 18650 battery holder and charging circuit.

With a BME 680, 2 seconds of measuring every 5 minute and esp-now protocol for sending, I estimate a 200+ day battery life. Esp-now protocol sends the message in a fracture of the time than wifi. Also you can tune the cpu & flash frequency depending on our workload. I have to wait 2s for the measurements to complete, so I lower the frequency to use less energy.