Hardware

Electronics

Currently DigitalRooster is built from these Components:

The total cost is about US$ 120 on digikey while the rotary encoder alone accounts for 25US$.

Caveats

The Raspberry Pi has few hardware PWM pins. One is used for SPI for the display, the other one I would like to use for Backlight control. Unfortunately the Pin is right next to the I2S pin for the speaker bonnet and may cause interference when connected through the speaker bonnet. As a quick fix I just cut the pin and soldered a flying wire from the Pi to the backlight pad of the TFT - not the most professional way to deal with EMI issues but it remedies the noise on the speakers.

Upcoming hardware DigitalRooster-MK3A

The third prototype of an extension PCB will have:

  • three audio channels with analog filters way better sound
  • a hardware shutdown line for the audio codecs so ‘off’ is really ‘off’ and there is no popping noise when changing tracks turning on.
  • Integrated Real Time Clock
  • I2C PWM LED driver for back-light and possible LED illumination. So you can wake up with a nice artificial sunrise next to your bed.
  • external I2C connection with interrupt line to support e.g. APDS9660 gesture and light sensor for dynamic back-light control and gesture snooze.

This will also be compatible with both Raspberry Pi and Banana Pi. So you have a wider choice of more powerful hardware!

rendering of red PCB

Casing

3D CAD view of the Casing

The housing is printed on a Prusa MK3. You can find the STL-files here.
Make sure you scale the housing with about 0.5% so the side panels fit in otherwise you will have problems mounting.