Summary

Minimalist remote controller for smart TV (or something else).

Remote controller with reduced instruction set. Massive 12 mm tactile switches in color. Arduino Mini. Optional small OLED display. Recycled mobile phone battery for power, USB charged.

Firmware : Less than 8k code size. Switch activation interrupt wakes processor from sleep, scans 16 switches for commands, OLED display shows command, IR diode drive. Repeat and power save.

In sleep state the 4-5-6-7 outputs are held low. Input 2 has the pull-up activated. Pushing a switch pulls 2 low via 4148 diode and activates interrupt. Processor wakes up, turns display on and scans keyboard. Fetches IR remote code from a table and drives IR LED. Scans keyboard again for code repetition. After timeout, turns off OLED and goes to sleep.

Copy your controller : choose keys to operate your smart TV. I found that 12 keys are enough for everyday use. Run the following to find out more about your remote : https://github.com/Arduino-IRremote/Arduino-IRremote. Determine the protocol your remote is using and arrange the selected 12 or 16 key codes in the tab[] array. Optionally you might want to display the name of the key so prepare a text array as well. You can remove the repetitive code parts from the array to save some memory, and add it only when sending code to IR LED.

Uncomment the "test" tab[] temporarily so you will see the indexes which are output when you push a key. Arrange the IR codes and text according to your key switch arrangement and you are done.

Use Serial.begin() etc. for building/debugging without the OLED display.

Construction : Lasercut 3mm plywood box, 3D printed lid. Switches on perfboard. Arduino Mini 168 8Mhz module for minimal power consumption. Disconnect power supply chip and LEDs of the Arduino, strip all unnecessary components using power. Processor runs on LiIon battery 3.6-4.2V. TFT 0.91" has its own PMOS power switch and built-in 3.3V regulator. TP4046 charger module has reduced current (1k2 resistor on pin2 of the chip is replaced by 6k8). Powerful IR LED with 13mm optical lens integrated in lid.

Files : PDF schematics, LYZ files for K40 laser, cut and ingrave layer. Paint was used to create the files.

Update : removed delay(1000); from the program list (displaying "Power down!") - it was useful for debugging only.