Honors project to make a sunrise alarm clock.
- I am currently revising the design to use less hardware.
Hardware/folder contains hardware schematics.Arduino_Test/folder contains Arduino sketches to test the hardware designs.- Will soon include
src/andinstall/directories for implementation code and installation.
Currently I have custom hardware designed to multiplex the seven segment display and to generate signals for the NeoPixel LED's. The speaker can be driven directly from the Raspberry Pi Zero.
The seven segment multiplexer has the following major components:
- 555 astable oscillator to generate a steady clock pulse.
- Four 8-bit shift registers to hold the digit values, driven by the 555 circuit.
- 7-bit counter to select which digit is active on the display.
The NeoPixel signal generation circuit has the following major components:
- 3.2768 MHz oscillator to drive a counter.
- Two 64-bit shift registers to store the light values.
- Two 4-input multiplexors to generate either 1 or 0 signals.
- 12-bit counter to control the shift register and multiplexors.
Currently, the NeoPixel signal generation circuit does not work consistently.
- One possible issue is the parasitic capacitance on the breadboard is too high and causes inconsistent timing.
- It is hard to debug the timing problems because I have cheap oscilloscope probes.
- The circuit is large and would be expensive for PCB manufacturing.
The future plans are to reduce the overall size of the hardware and fix the consistency of the NeoPixel signal generation.
- Use an ATtiny85 to generate the NeoPixel control signal.
- Utilize thread scheduling to multiplex the seven segment display. This should not need its own hardware because the timing requirement is on the order of milliseconds.