PulseSensor on CYD (Cheap Yellow Display)
PulseSensor on CYD
Standalone heartbeat display — no coding required
What's a CYD?
The Cheap Yellow Display (CYD) is the nickname for the ESP32-2432S028R — a $15 development board with a built-in 2.8" color touchscreen. Irish maker and YouTuber Brian Lough coined the name and built a thriving community around it. His GitHub repository is the go-to resource for CYD projects, from Spotify displays to retro game emulators.
We thought it would make a perfect standalone PulseSensor display — and it does.
What You Need
| CYD Board | ESP32-2432S028R — search "Cheap Yellow Display" on Amazon or AliExpress (~$15) |
| PulseSensor | Get one here |
| USB Cable | Micro-USB, must support data (not charge-only) |
| Browser | Chrome, Edge, or Opera (WebSerial support required) |
Wiring
Connect your PulseSensor's three wires to the CYD:
[INSERT: Wiring diagram or photo showing connections]
What You'll See
Once flashed and wired, your CYD becomes a standalone pulse monitor displaying:
- BPM — Large, easy-to-read heart rate
- Waveform — Smooth scrolling pulse wave across the full screen width
- IBI — Inter-beat interval in milliseconds
- Heart indicator — Flashes red with each heartbeat
When no finger is detected for 3 seconds, the display resets and shows "Place finger on sensor."
[INSERT: Photo or GIF of CYD showing heartbeat]
Troubleshooting
No serial port appears in the flasher?
Try a different USB cable — many cables are charge-only and can't transfer data.
Flat line on the waveform?
Check that the purple wire connects to GPIO 35 on the P3 connector.
Erratic readings?
Apply gentle, steady pressure. Make sure the back of your PulseSensor is insulated with the velcro dot from your kit.
For Developers
Want to customize the display or build from source? The full Arduino sketch is available on GitHub:
The code features flicker-free rendering, RGB LED heartbeat effects, and easy color customization through #defines at the top of the sketch. MIT licensed.
Questions? help@pulsesensor.com