Pulse sensor (analog): specs and pinout
An optical pulse (photoplethysmography) sensor: an LED lights the skin, a light sensor reads the reflected light, and the analog output follows the pulse waveform. For learning and experiments only. The specs are from the maker's PulseSensor datasheet for the original board; the listing may be a clone and its board is not covered. The output goes to an ADC, so it needs a board with an analog input (a Raspberry Pi has none).
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage Vdd | 3.0 V min, 5.5 V max | source Electrical specifications table, page 4 of 6 |
| Analog output voltage | 0.3 V min, Vdd/2 typ (signal baseline), Vdd max | source Electrical specifications table, page 4 of 6 |
| Supply current | 3 mA min, 4 mA typ | source Electrical specifications table, page 4 of 6 |
| Operating temperature | -40 to +85 C (electrical range, not a skin-contact rating) | source Electrical specifications table, page 4 of 6 |
| Sensor diameter | 15.8 mm | source Physical reference, page 4 |
| Populated thickness | 3.5 mm | source Physical reference, page 4 |
| Cable length | 610 mm (24 in) | source Physical reference, page 4 |
| Output type | Analog; read with an ADC input | source What it measures, page 1 |
Power
| Value | Source | |
|---|---|---|
| Supply | 3.0-5.5 V | source Electrical specifications table, page 4 of 6 |
| Current | 4 mA typ (3 mA min) | source Electrical specifications table, page 4 of 6 |
Pinout
Wire colours and specs are from the maker's PulseSensor datasheet (World Famous Electronics), which describes the original board. The listing may be a third-party copy whose board is not covered by an official document, so check its printed pin labels.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| Purple wire | Analog signal | 0.3 V to Vdd | source Page 4 | |
| Red wire | Vdd supply | 3.0-5.5 V | source Page 4 | |
| Black wire | GND | source Page 4 |
Build with it
Project ideas for the Pulse sensor (analog). Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Heartbeat LED: Power the sensor from the Uno 5 V pin and read it on A0. Add a resistor in series with the LED. Learning project only.
- Pulse waveform on OLED: Power the sensor from the 3.3 V pin so its output stays inside the ESP32 ADC range. Learning project; the maker's datasheet says it is not for diagnosis or patient monitoring.
- Pulse BPM on an LCD: Power the sensor from the Uno 5 V pin and read it on A0; the 5 V Uno also suits the LCD backpack. Learning project; the maker's datasheet says it is not for diagnosis or patient monitoring.
Common mistakes
- Feeding the analog output to a 3.3 V ADC while powering from 5 V: the signal can approach the supply voltage (source: link, page 4)
- Skipping insulation: the circuit board is exposed and must be insulated before skin contact (source: link, page 2)
- Connecting it to a board with no analog input: the output goes to an ADC (source: link, page 1)
Not covered by the official source
- Maker datasheet is for the original PulseSensor; the listing may be a clone.
- The cited edition C-RC2 is an unpublished candidate; the electrical values are stated to be retained from published revision B (2024-11). The English revision B PDF is no longer linked on the maker's datasheet page (only other-language 2024-11 copies).
- The listing title says Raspberry Pi compatible; the sheet sends the output to an ADC and a Raspberry Pi has none (flag to listing owner).