Design a small USB keyboard for playing osu!: Blog posts
In addition to mandatory keyboard functionalities, USB audio and Micro SD support are also added. So it's now called USB Mix.
The PCB layout was made compatible with the original Nosumor v3 casing, which sells on the official osu! store.
However, as a hobby project for learning USB framework and achieving high performance, the parts used in this design are probably unnecessarily expensive.
- USB 2.0 high-speed connection with 8kHz polling rate
- 5 switches (2x Cherry MX switches & 3x tactile switches)
- RGB lighting!
- Audio output through headphone jack using USB audio class 2
- Micro SD card reader
- Application for dynamic reconfiguration and firmware upgrade
- Audio input (MIC) through headphone jack
- MPU-9250 9-axis motion sensor
- ADC waveform capture
- DAC waveform generation
- 50×50 (mm) board area
- 2 mechanical keyboard switches (Cherry MX RGB compatible) and 3 tactile buttons
- Keycap and bottom-side RGB lighting
- STM32F722RE Cortex-M7 high performance MCU @216MHz
- USB 2.0 high-speed PHY USB3370
- 3.5mm audio jack with TLV320AIC3110 audio codec
- InvenSense MPU-9250 9-axis motion sensor
- On-board FT2232D connected to UART & JTAG for debugging
- Test points for 2xADC & 1xDAC
- Extension UART port with 3.3V power
Gerber files for PCB manufacturer Seeed Studio provided.
| Configuration | Cost |
|---|---|
| Basic keyboard | £20 |
| With audio and Micro SD slot | £30 |
| Also with debugging USB port | £38 |