HI. I am working on a project which will involve displaying colours for young children. There will be three physical sliders for each of RGB and the children can slide these and see the colours. The system will also display a random colour and the children have to match it with the sliders. I am using a PCF8591 to read the sliders. I want a small display (say 3.5") that I can attach to the pi to display the colours. If the display was touch sensitive that would be good. I need to still be able to get access to some of the GPIO pins, particularly 3 and 5 (SMBUS) and a few general pins for input.
Any suggestions for a suitable display please?
I have a Raspberry pi 4B and a Raspberry pi zeroW. I will probably use the 4B but if it also worked on the ZeroW that would be a bonus.
We have a few displays available around that size that have a touch screen. Unfortunately, they do connect via the 20x2 header and act as HATS to cover most or all of the GPIO including pins 3 and 5, which is going to be an issue.
Here are the screens to start with, I think the first one looks most ideal for your use case:
A cheaper alternative:
Or a stylus operated version:
Regarding the issue of access to the remaining GPIO - these following boards would be a fantastic way to keep the functionality of the screen sitting on top of the Pi while also allowing the rest of the GPIO to be accessed:
Here’s another alternative that expands your access to the Pi GPIO, but isn’t as clean and has spring terminals rather than extra available header pins:
Alternatively, perhaps use a ribbon cable on the Pi GPIO and extend them out to a protoboard or breadboard for creating parallel connections off the Pi.
I may not have covered all the bases here so hopefully someone may pull me up if there is a product I’ve missed!
I believe I spoke on the phone with you about this one, Welcome to the forum!
Initially, I was going to suggest an IDC cable like this one for connecting to some spare pins not used by the display, but since you’re after pins 3 and 5, these will be covered by any display using a 2x13 or 2x20 female header
In this case, I’d suggest a HDMI or DSI interface screen, here are a few models in differing sizes and technologies:
Thanks Matt and James. James, I am looking at the PiTFT Plus 480x320 3.5 TFT+Touchscreen for Raspberry Pi, although it appears to be out of stock. It says:
The display uses the hardware SPI pins (SCK, MOSI, MISO, CE0, CE1) as well as GPIO #25 and #24. GPIO #18 can be used to PWM dim the backlight if you like. All other GPIO are unused. There’s a 2x16 ‘classic Pi’ connection GPIO header on the bottom, you can connect a 26-pin Pi GPIO cable to it to use any of the other pins as you like.
I think there is a typo - should be 2x13. It seems that the pins I need would be available from that connector without the need for an expansion board. What do you thi8nk? Do you know when stock might be available please?
I just checked and you are correct - sorry I linked you to an out of stock product! There is currently no ETA on ADA2441 PiTFT Plus 480x320 3.5 TFT+Touchscreen for Raspberry Pi as our supplier also has no stock. Likely due to the worldwide silicon shortage affecting many electronic components. Apologies for that.
I think your plan was a good one though.
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