Help Launching Myself

[crbn60]

Good Morning,

I have solid Python experience, lots of Linux system experience, and lots of high-level system integration experience. But little electronics knowledge, only enough to be dangerous. Now, I want to go low and teach myself uPy and get my feet wet in the general field.

Due to the virus, I have the privilege of spending the next few months working remotely (from my day job) and want to take the opportunity to work on the following projects to monitor and control my little travel trailer (these are all completely separate and will require separate boards):

1. Communicate with my fridge via its serial interface to read data and send it commands;
2. Control my roof fan, probably by simulating its optional remote keypad using relays or other methods;
3. Record multiple voltage and temperature readings in my electrical system;

All of these would transmit telemetry using MQTT to my existing broker, either directly or using an onboard Linux host as a gateway. The trailer has a WiFi network.

My power source is a solar-powered 12v system, meaning it might see voltages from 10 through 16v. If my boards can not handle that, then I will need to find a good external power supply for them. I'm hoping some boards have that built-in, though.

Note: I need to place a large order(s) now for everything I could conceivably need, as I will not be able to easily procure components later. So I am looking for your collective advice as to where to start.

Cost is not a huge issue, since I won't be shipping hundreds of these things. I don't mind spending more to get reliability and simplicity.

Main Question:

Which development board will give me the most flexibility to do whatever I want along with good support so I'm not tripping over too many issues outside of my current knowledge? My general desires are smaller with WiFi.

Secondary Question:

Should I be looking beyond WiFi for this application? My Linux host (A balena Fin supporting a Pi CM) also has BLE, but I know nothing about it. I could also get a LoRaWAN card for the host and start working with that. (This may enable some future tinkering to collect data from other sources in a cottage…)

Please send me any and all thoughts or recommendations, I would really appreciate help starting this journey on the right foot.

Thanks to all that have made this incredible project a reality!

A.

[T-Wilko]

Hi A,

Your applications seem to not be overly time-sensitive or high frequency, so I would say the faster speed and interrupt times (thanks to the bare-metal uPy build) of a more expensive STM32 board are probably not required. Between the remaining popular platforms of ESP32 and ESP8266, I've found the larger amount of RAM (and often ROM) found on ESP32 boards comes in handy rather quickly.

As for a specific board that would meet your requriements, I'm not too sure. Your peak voltage of 16v means most regulators found on ESP32 boards (that I've tried) won't handle it. If cost isn't an issue, what I'd do would be to buy a suitable number of buck (step-down) converters that are cheap as chips on aliexpress/anywhere online instead.

In terms of suitable wireless methods, I would stick to WiFi for now as BLE documentation and example code is still a little lacking in comparison. But I suppose it depends on how adventurous you're feeling, especially since you say you have a few months to work at this!

If you're considering long range LoRa options to future-proof your system, having one of these as a tranceiver for your system might work well. It's an ESP32 board that has a Semtech LoRa chip, u-blox GPS chip (potential use maybe?), backup battery holder (to take over if your solar power system fails?) and also an on-board power chip (with uPy repo) to switch the aforementioned peripherals on and off to save power. Even better is the fact that I know that that board works well, as I own one myself and I've managed to get most features working on it in uPy!

Not sure if this was the sort of info you were after, but I hope it helps.

Thomas

[crbn60]

Your applications seem to not be overly time-sensitive or high frequency, so I would say the faster speed and interrupt times (thanks to the bare-metal uPy build) of a more expensive STM32 board are probably not required. Between the remaining popular platforms of ESP32 and ESP8266, I've found the larger amount of RAM (and often ROM) found on ESP32 boards comes in handy rather quickly.

Perfect, your advice is what I need: ESP32 it is.

I'll look for a good regulator. Anything specific I want, other than the correct output voltage and wide input voltage?

I will start with WiFi, your advice makes complete sense.

Are the LilyGO boards generally good quality?

For a basic WiFi board, I found these:

LILYGO® TTGO T7 V1.4 Mini32 ESP32-WROVER-B PSRAM Wi-Fi Bluetooth Module Development Board
https://www.aliexpress.com/item/3297737 ... 2246UcFf1b

LILYGO® TTGO T8 V1.7.1 ESP32 8MB PSRAM TF CARD 3D ANTENNA WiFi & Bluetooth ESP32-WROVER Micropython
https://www.aliexpress.com/item/3285142 ... 2246UcFf1b

I am not familiar with all the ESP32 terminology, what should I be looking for?

If you're considering long range LoRa options to future-proof your system, having one of these as a tranceiver for your system might work well. It's an ESP32 board that has a Semtech LoRa chip, u-blox GPS chip (potential use maybe?), backup battery holder (to take over if your solar power system fails?) and also an on-board power chip (with uPy repo) to switch the aforementioned peripherals on and off to save power.

That's a really neat board, I will order one to play with.

What about the PyCOM boards? The WiPy 3.0 looks like it also does what I need?

Not sure if this was the sort of info you were after, but I hope it helps.

That is exactly the kind of advice I was looking for, thank you very much for taking the time to reply.

[rcolistete]

TinyPICO board has ESP32 with PSRAM, high quality components, excellent documentation and very low deepsleep current (10-18 uA) :
https://www.tinypico.com/
[TinyPICO/ESP32] TinyPICO is live and available for purchase!
There are cheaper ESP32 boards with deepsleep current of up to 1 mA due to the choice of voltage regulator, etc.

[crbn60]

TinyPICO board has ESP32 with PSRAM, high quality components, excellent documentation and very low deepsleep current (10-18 uA) :
https://www.tinypico.com/
[TinyPICO/ESP32] TinyPICO is live and available for purchase!
There are cheaper ESP32 boards with deepsleep current of up to 1 mA due to the choice of voltage regulator, etc.

The TinyPICO looks nice, unfortunately it is sold out everywhere that I looked.

Do I need an RTC?

[rcolistete]

The TinyPICO looks nice, unfortunately it is sold out everywhere that I looked.

Pimoroni has :
https://shop.pimoroni.com/products/tinypico