This is a strange way to do this. Linux already supports such displays to be used as a real framebuffer. Why all the python and screenshotting?
Couldn't make it work with those modules.
Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
11–20 of 136 posts
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#12There is a weird spot in the display market that is painful as a embedded developer:
Displays under 400x240 pixels, usually the gfx buffer can be managed in the ram of the MCU. Nothing fancy needed, can get decent framerate on SPI bus running at 16 MHz. Anything above this range gets super ugly: no good displays exist and if they do, they're expensive or outdated (800x480 resolution is basically impossible to obtain). Furthermore, driving this display requires crazy shit like multiple SPI channels (QSPI), or some neutered version of DSI protocol...impossible to find docs for and if they have docs, theyre in Chinese.
Then there are ultra high resolution displays, for e.g. cell phone market or laptop screens. You're now looking an entirely different beast. MIPI/DSI hardware support is required and a bunch of NDAs, need dedicated GPU and a proper linux running.
Ideal display tech would be 5"inch diagonal, OLED (low power consumption), 800x480 (or similar) and can be run using ARM Cortex-M4 or similar microcontroler arch. That would open up opportunities for so many device categories that doesn't exist today. Imagine a VT100 terminal clone running on 8" 1024x768 resolution screen with a cheap ESP32 + display driver chip. Or a slightly more beefy Cortex-M7 running zephyr/linux. So many things we could build.
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#13where would I get the display for 2 USD?
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#14There is a weird spot in the display market that is painful as a embedded developer: Displays under 400x240 pixels, usually the gfx buffer can be managed in the ram of the MCU. Nothing fancy needed, can get decent framerate on SPI bus running at 16 MHz. Anything above this range gets super ugly: no good displays exist and if they do, they're expensive or outdated (800x480 resolution is basically impossible to obtain)…
It's an interesting challenge, but MIPI DSI is sort of the right interface for small size displays too high resolution to drive with SPI. There are a range of Cortex-M4 and M7 MCUs that have DSI output (e.g. https://wiki.st.com/stm32mpu/wiki/DSI_internal_peripheral). The solution is probably just better documentation for the panels and their DDICs.
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#15Earlier quoted context omitted.
Other than watch-like functions, can you give me some ideas?
watch lofi hip hop radio, of course. https://learn.adafruit.com/lofi-hip-hop-raspberry-pi-radio-b...
That's pretty cool. That joystick looking thing made me think it would be cool to have some old school knobs to change the (youtube) channel.
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#16You may think this is "tiny", but I got a lot done on my Apple ][ back in 1978 with a 280x192 pixel display.
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#17Earlier quoted context omitted.
Other than watch-like functions, can you give me some ideas?
Originally I was just using it to display the IP addresses after reboot on a smaller 0.96" 80x160. Then a screen shot... then zoom. I'm thinking more about some QR code with basic sysinfo.
QR for status or info on anything is the winner here...
can you array these off a single PI?
Imagine this:
An installation where there is an array of these screens - they are associated with whatever you want info on - they cycle btwn a screenshot of the item, some basic text (like IP/UPC/Barcode/QR to a fully detailed product/item page, uptime/health status...) etc...
And you can just have a PI running a bunch of these on a 42" rack, or on shelves of retail items etc....
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#18where would I get the display for 2 USD?
I got them from AliExpress - Google for ST7789 240 IPS TFT
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#19You may think this is "tiny", but I got a lot done on my Apple ][ back in 1978 with a 280x192 pixel display.
You’re 280x192 pixel display was probably 13” or even larger. This display is 1”x1”. You can get about six lines of 12-15 characters on it if you want to be able to read it from further than 6” away.
Re: Show HN: Raspberry Pi 400 with a $2 IPS 240x240 micro display
#20This seems really great for times when I want to boot up a PI but don’t want to bother with finding a display and PSU for that display, and I don’t want to unplug my computers display. A quick display for simple things.