While everybody seems to use a smartphone to get up in the morning, I still prefer a dedicated alarm clock. Since no available alarm clock matched all my requirements, I decided to build my own.
Requirements:
- Solar powered
- Long standby time (in the dark)
- Play music from SD card
- Dedicated "+8h" quickset alarm time button
- Warn before the battery runs out (the old one failed to do this)
- Radio controlled
The final clock is a 6cm cube (hence the name) full of batteries, circuitry and cables:
- Arduino-compatible ATmega328 @ 8 MHz
- DS3231 Real-Time Clock with a 3V lithium backup battery (>9 years runtime, temperature compensated = super precise!)
- DCF77 receiver with antenna that should be able to receive a time signal in all of Europe
- TPA2016 2.8W audio amplifier (+ speaker)
- 0.3 W solar cell
- 3 * 1.2V AAA battery (months of standby in the dark)
- Micro SD card socket
- 7-segment leds, buttons
This repo contains the design of the 3D-printed case, the circuit diagram and the software running the clock.
Several additional arduino libraries are required to compile the software:
- https://github.com/tfg13/DS3231 (to control the RTC)
- https://github.com/tfg13/TMRpcm (to play music from the sd card)
- https://github.com/adafruit/Adafruit-TPA2016-Library (to control the amplifier)
- https://github.com/greiman/SdFat (to access the sd card (official sd library cannot handle re-opening the card after sleep))
License:
- My code: Apache 2.0 (see LICENSE_code)
- Design for case, circuit: CC4 (see LICENSE_case_circuit)
(c) 2014-2015 Tobias Fleig - All Rights Reserved