Need a low profile RGB pushbutton with removable cap. Ideas?
T Chap
Posts: 4,198
I made a controller with an MX non tactile PCB TH mount with removable clear keycap. I'm looking for a low profile (shorter) alternative. This one with cap and switch is around 1". There is a WS2812 next to each button to color code the cap for visual reference. Ideally I'd like to find an RGB button internal alternative but worst case have some LED in it to backlight the text paper inside the keycap. This alternative shown on Ali is a good looking replacement, it is listed as tactile with a click which is not a good feature(ideally silent). Cherry seems to be showing an RGB LED option with 4 pins on the LED, so it would need a dedicated chip to control from the Prop. This is minimum 32 buttons, up to 48, 56. The Cherry on Digi is .71USD in <1000 pieces and the keycaps are .50USD although I just found an alternative for the cap for much cheaper in china.
Does anyone know of an option to get a 1/2" x 1/2" approx keycap, <1/2" high with removable cap that the end user can easily manage to pop off? I see vendors with a 250USD device with 32 OLED displays, I see the cheapest version of those at 17USD on Ali, 32 x 17 is more than 250 retail, not sure what their source is or volume. The cost is a factor on this, so I'm trying to beat the WS2812 + switch + cap. I have a thousand SW2812 on a reel that was not even 150 so those are cheap in bulk. But adding a controller to a standalone LED will be a cost. Prop is the controller.
Any ideas? Thanks for suggestions.
Comments
I should think there would be an 8-pin PIC or AT chip (<$1) that could be installed on a DIY pcb under your 4-pin switch and act as an addressable multi drop controller, maybe not the '2812 protocol, but something like that. But alas, I couldn't find any exact fit either.
But there was this:
Serial Controlled RGB LED PWM Driver PIC12F629 based PWM controller for RGB LEDs
It is unidirectional input only at 9600 baud, data to control the RGB levels. But with 5 data lines on a PIC12F629, 1 for open drain coms and 3 for the RGB, you could use the additional line with a scheme to read and return the button status, debounced even.
There are these that come in an RGB version:
https://www.mouser.com/datasheet/2/140/ESCH_S_A0000503984_1-2545623.pdf
The datasheet doesn't indicate whether the keycaps are removable, though.
-Phil
Some NKK's KP series push button switches on Digi-Key and Mouser seems like a possibility. 0.5" square removable key cap, RGB, but you would need to control each LED individually in the switch. Most seem to run between USD$10-20. Then again, if it is a one-off, maybe take a cheap standard part with the removable keycap and replace its light with a ws2812 internally if it can be done or under the snap off keycap if a flexible enough connection can be made
Thanks guys for the tips. I just talked to Cherry and they recommended a low profile version of the MX called MX1B-52NA which is quite a bit shorter. I am going to drop the LED for now as there is no perfect solution to suit the need to low cost and simplicity, and look for a clear keycap to make it easy to drop in a graphic.
Actually I found a nice solution. There is a similar part to that Cherry by Kailh called the Choc V2 that is low profile, uses standard MX key caps. There is an LED window in the bottom just over 5m wide which will allow the WS2812 to fit with just a minor plastic mod to the bottom of the switch( cut or melt a notch). This would be a simple mod.
Probably way off the mark here but I have been considering something like this for a smart-switch.
It's the Picomite that plugs directly into the back of a waveshare display/touchscreen.
This particular graphic is quite large and so it requires the on-board SD.