Hardware & Modules
Everything about the physical side of Palpable -- the Pi, the modules, and how they connect.
The Raspberry Pi Zero 2 W
This is the tiny computer at the center of your setup. It's about the size of a stick of gum and runs the Palpable bridge software, which talks to your sensors and connects to the cloud.
Things to know:
- WiFi: Only works on 2.4 GHz networks. If your router has both 2.4 and 5 GHz, make sure you're connecting to the 2.4 GHz one.
- Power: Use a USB-C charger rated at 5V, 2.5A or higher. Most phone chargers work. Avoid powering it from a laptop USB port -- it usually doesn't supply enough power.
- SD card: Needs at least 8 GB, formatted as FAT32. Most new cards work out of the box.
Other Raspberry Pi models may work but are not officially tested. The Pi Zero 2 W is recommended because of its small size, low power consumption, and WiFi support.
Connecting modules
All Palpable modules use the Qwiic connector system. These are tiny 4-pin cables that click into place -- no soldering, no wiring diagrams, no pin counting.
How to connect
- Find the Qwiic port on your Pi (or a Qwiic adapter board if your Pi doesn't have one built in)
- Click a Qwiic cable into the port
- Click the other end into your first module
- To add more modules: each module has two Qwiic ports. Plug a cable from the second port to the next module. You can chain them like this:
That's it. The Pi automatically detects every module on the chain.
Good to know
- Hot-swappable -- add, remove, or swap modules at any time without powering off. The Pi detects changes automatically.
- Up to 8 modules can be chained reliably
- Order doesn't matter -- the Pi finds them all regardless of position
- Keep cables short -- total cable length under 50 cm works best. Longer runs can cause connection issues.
Module not detected? Try these steps in order: reseat the cable on both ends, try a different cable, shorten the chain, power-cycle the Pi (unplug and replug USB-C).
Available modules
Palpable supports 30+ plug-and-play modules. Here are the most popular ones:
Sensors (they measure things)
| Module | What it measures |
|---|---|
| Modulino Thermo | Temperature and humidity |
| BME280 | Temperature, humidity, and air pressure |
| SCD41 | CO2 concentration |
| SGP40 | Air quality (volatile organic compounds) |
| Modulino Distance | Distance to the nearest object (up to 2 meters) |
| ICM-20948 | Motion and orientation (accelerometer + gyroscope) |
| MAX30101 | Heart rate and blood oxygen |
| NAU7802 | Weight (with a load cell) |
| VEML7700 | Ambient light level |
Inputs (you interact with them)
| Module | What it does |
|---|---|
| Modulino Knob | Rotary encoder (turn to change a value) with push button |
| Modulino Buttons | 3 tactile buttons, each with an RGB LED |
| Modulino Joystick | Analog joystick with push button |
| Qwiic Button | Single illuminated button |
| Qwiic Keypad | 12-key number pad |
Outputs (they do things)
| Module | What it does |
|---|---|
| Modulino Buzzer | Plays tones (100-10,000 Hz) |
| Modulino Pixels | 8 individually addressable RGB LEDs |
| Modulino Light | Single LED (adjustable brightness) |
| SSD1306 OLED | Small screen (128x32 or 128x64 pixels) |
| Qwiic Relay | Controls high-power devices (lights, fans, pumps) |
Modules are available in the Palpable store inside the app. Want support for a new module? Request it on our feedback board (opens in a new tab).
Status LED
Your Pi has a small LED that communicates what's going on:
| What the LED does | What it means |
|---|---|
| Stays on | System is booting up. Wait about 30 seconds. |
| Blinks slowly (1x per second) | Connecting to WiFi or the cloud. Wait. |
| Blinks fast (4x per second) | Something went wrong. Check WiFi credentials or power supply. |
| Off | Everything is running normally. |
The button
Your Pi has a physical button that provides quick controls:
| What you do | What happens |
|---|---|
| Short press (under 2 seconds) | The LED flashes to show device status |
| Long press (hold for 10+ seconds) | Factory reset -- clears all settings. You'll need to re-flash the SD card. |
Changing WiFi after setup
If you move your Pi to a different network:
- Power off the Pi and remove the SD card
- Open the SD card on a computer
- Edit the file at
palpable/settings.txt - Update the
WIFI_SSIDandWIFI_PSKlines with your new network details - Put the SD card back and power on
Or, generate a fresh setup from the Palpable app (Devices > Add Device) with the new WiFi credentials and copy it to the SD card.
Power tips
- Use a dedicated USB-C charger, not a laptop USB port
- If your Pi keeps rebooting or losing WiFi, the power supply is probably too weak
- Modules with LEDs at full brightness (like Modulino Pixels) draw more power. If you have 6+ modules and see instability, try a stronger power supply