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Hex Color Picker Input Board Powered By Raspberry Pi Pico

Written by Stephen Vicinanza

The Dial Toner, developed by Guy Dupont, is a hex color picker input board powered by Raspberry Pi Pico. Dialing in hex values for LED colors just got easier. The Dial Toner is powered by Raspberry Pi RP 2040 and is small and very efficient. It is a hardware alternative way to find the exact color you want, for a couple of LEDs, that could be used in other projects.

There is a bit of fun to be had here, in a simple straightforward the Dial Toner works. There are six different potentiometers with stops at each setting, that can be twisted and turned to dial in a specific value. There is A-F and 0-9 that can be dialed in using the knobs to dial in a preferred hexadecimal string that corresponds to a particular color.

A LED is housed inside a clear keycap and shows the desired color. Pressing the key registers the color with the interface Dupont developed.

The interface can also be used to convert the hex value to other formats through a built-in tool, those other formats include CMYK, HSV, and RGB. The biggest additional benefit of this tool is the ability to see a digital value that corresponds to the real-life RGB LED color. This is a quick way to program RGB LEDs for multiple projects, making sure that you get the color you want right from the start.

The Dial Toner project required a custom PCB, that uses an XIAO RP2040 module as the main driver. There are two RGB LEDs onboard including one inside the4 mechanical button and one on the bottom of the board.

USB-C port is available for power and connecting to a PC. Any “choc” style keycap interface can be used, to replace the original keycap.

Dupont has stated in a statement that the board is programmed from scratch using CircuitPython. The CircuitPython code handles the potentiometer input to set the LED color value. The code also sends the command to set the color to the PC, by simulating a keyboard interface. The original thread was shared on Twitter and has a video of the color picker in action setting up an LED color.

The Dial Toner is still in development, and there is an availability of prototypes, that are fully functioning and work well. There are some upgrades coming but Guy Dupont’s Etsy page has the latest prototypes for sale.

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For the past 8 years, I have been writing about embedded technologies, added to my technical, academic, and medical editorial experience, with companies like Elsevier and Cambridge University Press. I tell people to read what I write, not try to pronounce my last name. I am always available for comments and suggestions you can reach me at and I promise I will take the time to reach back out to you. I live in the North East with my wonderful family.

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Hex Color Picker Input Board Powered By Raspberry Pi Pico

by Stephen Vicinanza time to read: 2 min