What it is?

This project is a custom-designed, battery-powered wireless remote control built around the ATtiny816 microcontroller and the nRF24L01+ 2.4GHz RF transceiver. It features a fully integrated power management system with USB-C Li-Po/Li-Ion battery charging, a smart push-button on/off controller, tactile buttons for user input, and multi-color LED status indicators. It also includes an onboard USB-to-serial bridge to allow for seamless firmware programming and debugging directly through the USB-C port.

Why have I built it?

Many of the DIY remote controls based on NRF24 use ready made modules. Since I was stubborn to use the shell of a remote control found in the garbage, I had to experiment with NRF24 on PCB and inverted F antenna, to make it compact.

How to use it?

Power it on: Use SW4 (bottom right) button to power on the device. To power off, long press the same button. Of course, connect it to a LiPo battery using the J2 connector.

Program it: The ATTiny816 can be programmed via USB-C through UDPI protocol running. The CH340 chip takes care of the translation from D+/- to UDPI pin.

Charge it: The remote is equipped with a MCP73871 charger chip. The load sharing feature enables power source selection (USB or Adapter) to supply system load while simultaneously charging the battery.

Notes:

Revision A of the board was successfully tested. Hope to upload some videos soon.

Revision B has the USB C on the front of the board. The decision to have the USB on the back was conscious to fit into the shell of the remote control. Thinking the community will 3D print the shell, it makes more sense to leave the back of the board empty to fit a battery.

The design of the inverted F antenna is from here.