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Comment by darkwater | Hacker News Reader

Unrelated but trying the HN wisdom here: any suggestion for a cheap touchscreen with a CPU attached and a battery that can be used as a control panel for Home Assistant? Yeah, probably some Android tablet but something that actually works well for this job and costs as less as possible? I cannot power it properly where I want to put it so it needs battery and then I can charge it as needed. Suggestions?

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Something like a SenseCap from Seeed Studio?

https://www.seeedstudio.com/SenseCAP-Indicator-D1S-p-5645.ht...

Oh, nice! maybe not as central controller (that would be still better on a bigger screen) but for each room control it could work very well! Thanks for the idea!

I just got a couple of ESP32-S3 devices direct from China (AliExpress), one with a 5" TFT screen and the other with a 7".

I don't know what home assistant is, but these will run C++ or MicroPython just fine. My application is an industrial controller and they are really nice. Dirt cheap at around $30 each shipped (arrived in just over 2 weeks) to USA.

[edit] They have very little I/O since the display is driven in parallel mode and that takes up most of the EPS32 pins. There's a SPI connector and a couple other pins that could probably be redirected for I2C. I haven't gotten around to to checking that. I did use one of the available pins for serial input to read a GPS module and that was trivial to setup though.

I use an stm32f103 as an io extender for my esp32-a1s, they cost about 2$ per board and the chip programmer cost about 10$. I use I2C to communicate between the esp32 and the stm32.

I do my development in VSCode using platformio with the Arduino framework and FreeRTOS. It is really convenient to have the same os and framework used for all the MCUs of a project. That's why I use the 2$ stm32 instead of a 1$ stm8.

Yeah, I decided to use an "Arduino" 10MT "PLC" board as my I/O extender since it comes with optically isolated inputs, 4-20mA analog input and a 24VDC power input, all of which I can use. At the improbable price of $22.75!

Thank you, I did not know about those PLC, it's incredible what you can obtain for that price.

You can find used iOS devices that run iOS 15, and therefore modern safari, for like $80.

Agree with this. You want something with the least headaches as possible. You should be able to run the the Home Assistant App as well.

If you get a old iPhone and buy a replacement battery still more than likely be cheaper than buying a Rpi + screen + lipo-hat + battery.

Does it even need to be a current version? If it's only used to access the web interface of a local device that you trust, I've wondered if you couldn't get away with an even older device/OS/browser. The only problem I can think of is if ex. HA ships an update that uses newer browser features, and even that wouldn't be a problem if you did the dashboard custom.

You'd be able to strap something together with a Pimoroni Hyperpixel and a raspberry pi with a lipo hat, if that was a direction you wanted to go in. It's a very nice little screen. No idea about how power efficient it is, though.

I mean, You are spot on -- A cheap android tablet sounds like the fastest/best/most aesthetically pleasing option. Otherwise Waveshare screen + some PI board is the "easy hacker-aesthetic way"

Kindle tablets with fully Kiosk browser.

m5stack.com

I love M5Stack and in fact just shipped my first project with an M5 Tough. However, those screens are tiny. Even 3" would be a huge improvement.

True that. They do have a phone-size e-reader device which is great, but obviously is subject to the limitations of e-ink. I suggest reaching out to them, they're very responsive on Twitter and @lovyan3 has developed a universal graphics library for the ESP32 stack and works closely with them.

Sorry, that's @lovyan03 if you were looking to follow up.

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