This Microchip ATtiny84-Powered 3D-Printed Remote Improves Accessibility for the Visually Impaired

Pseudonymous maker "lhm0," who recently released 3D-printed breadboards for wider microcontroller boards, has built a chunky infrared remote designed for accessibility by visually impaired users, with a satisfying 3D-printed shell and low-power operation driven by a Microchip ATtiny84 microcontroller.

"Modern TV remotes are often full of tiny buttons and complicated features," lhm0 complains of the problem that inspired the build. "This project shows how to build a simple, tactile, and accessible TV remote for visually impaired users that focuses only on what really matters: power, volume, and three direct channel buttons. The remote was specifically designed for Philips televisions and uses the RC6 infrared protocol for full compatibility."

The 3D-printed shell, held together by M2 screws and nuts, houses a custom-built PCB with six push-button switches and Microchip's low-cost eight-bit ATtiny84 microcontroller, plus a transistor, infrared LED, battery connector, and programming header. As the name implies, the ATtiny84 isn't exactly a powerhouse: the eight-bit AVR-architecture part offers just 512 bytes — not kilobytes — of static RAM (SRAM) plus 512 bytes of non-volatile electrically erasable programmable read-only memory (EEPROM) and a somewhat more generous 8kB of program storage.

Being as simple as it is, though, can be an advantage: as well as its low cost, the part doesn't need much power. Running the remote control code — which wakes from sleep when a switch is being pressed then triggers a preprogrammed infrared transmission — takes so little power that its creator estimated the remote can run for years on two AA batteries.

"A special detail is the battery contacts," lhm0 notes. "Instead of using a complete battery holder, this design uses the spring from a standard AA battery holder, which is removed from a commercially available part. For both battery contacts, place an M3 nut into the corresponding recesses in the printed enclosure parts. Solder the wires to cable lugs, then fix them to the M3 nuts using short M3 screws. This creates robust and reliable battery contacts."

The build is detailed in full on Instructables, with 3D print files, PCB files, and source code on GitHub under the reciprocal Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license. The maker has also shared a simple Raspberry Pi Pico project for capturing signals from an existing infrared remote, if your target device isn't a Philips TV.