4 layers92.7 × 63.1 mm
555 doom kicad
nickbild/555_doom_pcb
The circuit plays the opening riff from "At Doom's Gate" without a microcontroller, computer, or any software.
89 parts1MIT
2 layers
Alarmclock
trstephen/alarmclock1ceng 299 project - an STM32F407 functions as an alarm clock. It plays .mp3s
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 43
- Nets
- 56
- Pads
- 151
- Tracks, vias
- 412, 115
- Routed
- Yes
- KiCad
- KiCad 3
- Created
- 5 Jun 2015
- Updated
- 12 Aug 2015
Overview
Alarmclock is an open-source printed circuit board by trstephen, from the trstephen/alarmclock repository on GitHub. It is a 2-layer board with 43 parts on 56 nets, routed with 412 tracks and 115 vias.
It is built around the LM386 and 74HC14. Its parts include 23 resistors, 5 capacitors, 5 transistors, 4 connectors and 1 IC. It belongs with the lEDs and displays boards and the STM32 boards of this library.
Main components
2
LM386
SOP-80.2% 0℃~+70℃ 4V~12V 4mA 50dB 700mWx1@8Ω Analog voltage gain SOP-8 Audio Amplifiers ROHSGcoreAudio Power OpAmps
74HC14
SOP-14-40℃~+85℃ 1.9V、3.98V、4.4V、5.48V、5.9V 100mV、260mV、260mV 20uA 25ns@4.5V,50pF 2V~6V 6 74HC Noise suppression function Schmitt trigger SOP-14 Inverters ROHSJSMSEMIInverters
README
README.mdalarmclock
What is CENG 299?
CENG 299 is a second year project course at the University of Victoria. Students execute the full design cycle to create an alarm clock with mp3 audio playback capabilities. A STM32F407VG microcontroller is responsible for handling I/O, decoding the mp3 and generating the audio output. A custom-designed PCB filters and amplifies the audio output from the STM and contains the circuitry for driving the 7-segment display and cleaning up button input.
What's in the repo?
Schematics
Detail the four main components of the circuit design:
- I/O
- Audio amplification and filtering
- External button connections
- 7-Segment display controller
The files will open natively in KiCad.
Printable schematics, with some helpful notes, are here.
TODO: Include files for the PCB.
Code
A skeleton was provided that handles the USB On-The-Go communication and audio decoding. The bulk of the project code is in:
main.c
state_machine.c
buttons.c
clock_display.cThe included .coproj file will open the project in CoIDE but the project should work wherever the GCC-ARM compiler is used.
Known Issues
- mp3 playback
- Only works with 128kb/s encoding
- Stops playback after ~2min and needs to be hard reset before playback can continue
Parts
43| Qty | Value | Footprint | References |
|---|---|---|---|
| 9 | 300 | R3 | R1, R2, R4, R5, R6, R7, R8, R9, R10 |
| 5 | 100k | R3 | R14, R15, R16, R17, R18 |
| 5 | 1k | R3 | R3, R20, R21, R22, R23 |
| 5 | 2N3906 | TO92-CBE | Q1, Q2, Q3, Q4, Q5 |
| 2 | 10k | R3 | R11, R12 |
| 2 | CONN_2 | PINHEAD1-2 | P4, P6 |
| 2 | P*** | 1pin | 1PIN, 1PIN |
| 1 | .047uF | C2 | C3 |
| 1 | 0.01uF | C1 | C5 |
| 1 | 10 | R3 | R13 |
| 1 | 100uF | C1V8 | C2 |
| 1 | 220uF | C1V5 | C4 |
| 1 | 2N7000 | TO92DGS | M1 |
| 1 | 74HC14 | DIP-14__300 | U1 |
| 1 | 800pF | C1 | C1 |
| 1 | CONN_02X12 | pin_array_12x2 | P3 |
| 1 | CONN_3 | PINHEAD1-3 | P5 |
| 1 | LM386 | DIP-8__300 | Audio2 |
| 1 | R | R3 | R19 |
| 1 | STM32_F4_DISCOVERY | STM32F4DISC | STM1 |
Questions
What parts does the Alarmclock use?
43 parts, built around the LM386 and 74HC14. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Alarmclock KiCad files?
From the trstephen/alarmclock repository on GitHub, at the commit this page was made from: the board is kicad/alarm_clock.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Alarmclock design in my own project?
Its repository states no licence, so its author keeps all rights: ask trstephen before reusing the design.
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