HealthyPi 5 Vital Signs Monitoring HAT Kit ₹24,995 Add to cart

Getting Started NEXT firmware

Hooking up the Sensors

Last updated Jul 10, 2026

This page walks through preparing the device, preparing the body, and connecting each sensor cable correctly so you get clean signal traces from your first measurement.

1. Inspect the device

Before you connect anything:

  • ECG electrodes — the disposable Uni-Gel electrodes are single-use, snap-on style with a thin layer of conductive gel. Check that the gel is intact and the snap is undamaged.
  • SpO₂ probe connector — the male connector inside the SpO₂ port has nine pins. Confirm none are bent or missing.
  • SpO₂ probe clip — wipe off any dust or dirt. The optical window needs to be clean.
  • Probe connectors on the HealthyPi 5 itself — keep them clean and free of debris.

2. Prepare the skin

Skin is a poor conductor, so a few seconds of prep makes a large difference to ECG trace quality:

  1. Avoid placing electrodes over hairy skin. In rare cases you may need to shave the contact area.
  2. The skin should be dry and oil-free — dead skin and oils dramatically increase contact resistance.
  3. Briskly rub the skin dry to bring blood flow to the surface.
  4. Press each electrode firmly so it makes full contact with the skin.

3. Connect the sensor cables

Each physiological signal has a dedicated input on the device — connect them to the correct ports.

Signal Cable Connect to
ECG + respiration ECG probe ECG probe connector
PPG + SpO₂ SpO₂ probe SpO₂ probe connector
Temperature Temperature Qwiic cable Qwiic port

Sensor cables connected to the HealthyPi 5 main board

Carrier board users

The temperature Qwiic cable can also plug into the Qwiic ports on the HealthyPi 5 carrier board if that’s more convenient for your wiring.

4. Place the sensors on the body

ECG (3-lead)

  1. The ECG cable has three leads: Right Arm (RA), Left Arm (LA), and Left Leg (LL). Snap each lead onto a disposable electrode.

    Three disposable electrodes snapped onto the RA, LA, LL leads

  2. Stick the electrodes to the body in the standard 3-lead positions (right shoulder, left shoulder, left flank or hip).

    Electrode placement on the body for 3-lead ECG

  3. Connect the cable jack to the ECG port on the HealthyPi 5.

SpO₂

  1. Open the upper and lower jaws of the SpO₂ probe clip and place your index finger at the base of the clip.

    Opening the SpO2 probe clip onto the index finger

  2. Slide the finger forward until it’s positioned over the sensor window, with the fingertip against the inside finger stopper.

  3. Orient the probe so the cable runs underneath the hand (not over the back of the hand).

    Correct SpO2 probe orientation with cable underneath the hand

If the index finger isn’t usable

A smaller finger works as a substitute. Avoid the thumb — it produces less reliable readings.

Temperature

  1. Plug the temperature Qwiic cable into the Qwiic port on the main board.

    Temperature Qwiic cable plugged into the Qwiic port

  2. Hold the stainless-steel contact at the end of the temperature cable against your skin to get a reading.

Two temperature sensors exist in the wild

Older kits ship a MAX30205 (I²C address 0x49); newer kits ship an AS6221 (address 0x48). The firmware probes for both at boot and adapts automatically, so you don’t need to know which you have. The only practical difference is resolution — 1/256 °C per LSB on the MAX30205, 1/128 °C on the AS6221.

Your HealthyPi 5 is now ready for vital monitoring.

After the session

  1. Power off the device.
  2. Disconnect all cables.
  3. Store the kit in the silver anti-static cover that ships with the unit.

Power options

The board can run from either:

  • A USB-A-to-C cable (not included)
  • A 3.7 V / 2000 mAh LiPo battery — ensure it’s charged

The main board has integrated power-path management, so you can leave the battery connected and just plug in USB to top it up.

Once everything is connected, pick a firmware path — Arduino Quick Start if you want to write code, or the ready-to-run firmware if you just want signals on screen.

What to avoid

For best signal quality and accuracy

  • Don’t use the thumb for SpO₂ — readings will be inaccurate.
  • Don’t take SpO₂ readings in bright direct light. Cover the probe with an opaque material if needed.
  • Don’t tape the SpO₂ probe shut. The venous pulsation from a tightened clip distorts saturation.
  • Don’t push your finger too far in — past the stopper distorts the probe’s optical alignment.
  • Don’t reuse disposable ECG electrodes. They dry out and lose conductivity.
  • Don’t submerge the temperature sensor in any liquid — it’s a skin-contact sensor only.
  • Be aware of factors that affect SpO₂ accuracy: excessive motion, nail polish, intravascular dyes, very poor finger perfusion, extreme finger sizes, or incorrect placement.