meshtastic/docs/configuration/gpio-peripherals.mdx

---
id: gpio-peripherals
title: Configuring GPIO Peripherals
sidebar_label: Setup GPIO Peripherals
slug: /hardware/peripheral/
sidebar_position: 6
---

## Remote Hardware

:::warning
GPIO access is fundamentally dangerous because invalid options can physically damage or destroy your hardware. Ensure that you fully understand the schematic for your particular device before trying this as we do not offer a warranty. Use at your own risk.
:::

### Supported Operations

- Set any GPIO
- Read any GPIO
- Receive notification of changes in any GPIO

### Setup

You can get the latest python tool/library with `pip3 install --upgrade meshtastic` on Windows/Linux/OS-X. See the [python section](/docs/software/python/cli/installation) for more details.

To prevent access from untrusted users, you must first make a `gpio` channel that is used for authenticated access to this feature. You'll need to install this channel on both the local and remote node.

The procedure using the python command line tool is:

1. Connect local device via USB
2. Create a GPIO channel:
   ```shell
   meshtastic --ch-add gpio
   ```
3. If doing local testing, you may also want to change the speed of the channel:
   ```shell
   meshtastic --ch-mediumfast
   ```
4. Check the channel has been created and copy the long "Complete URL" that contains all the channels on that device:
   ```shell
   meshtastic --info
   ```
5. Connect the remote device via USB (or use the [remote admin](/docs/configuration/remote-admin) feature to reach it through the mesh)
6. Set it to join the gpio channel you created:
   ```shell
   meshtastic --seturl theurlyoucopiedinstep3
   ```

Now both devices should be able to talk over the `gpio` channel. Send a text message from one to the other to verify. Also run `--nodes` to verify the second node shows up.

### Masks

To determine the appropriate mask for the pin(s) that you want to know. The python program (and output) below might help:

```python
>>> for i in range(1,45):
...     print(f'GPIO:{i} mask:{hex(2**i)}')
...
GPIO:1 mask:0x2
GPIO:2 mask:0x4
GPIO:3 mask:0x8
GPIO:4 mask:0x10
GPIO:5 mask:0x20
GPIO:6 mask:0x40
GPIO:7 mask:0x80
GPIO:8 mask:0x100
GPIO:9 mask:0x200
GPIO:10 mask:0x400
GPIO:11 mask:0x800
GPIO:12 mask:0x1000
GPIO:13 mask:0x2000
GPIO:14 mask:0x4000
GPIO:15 mask:0x8000
GPIO:16 mask:0x10000
GPIO:17 mask:0x20000
GPIO:18 mask:0x40000
GPIO:19 mask:0x80000
GPIO:20 mask:0x100000
GPIO:21 mask:0x200000
GPIO:22 mask:0x400000
GPIO:23 mask:0x800000
GPIO:24 mask:0x1000000
GPIO:25 mask:0x2000000
GPIO:26 mask:0x4000000
GPIO:27 mask:0x8000000
GPIO:28 mask:0x10000000
GPIO:29 mask:0x20000000
GPIO:30 mask:0x40000000
GPIO:31 mask:0x80000000
GPIO:32 mask:0x100000000
GPIO:33 mask:0x200000000
GPIO:34 mask:0x400000000
GPIO:35 mask:0x800000000
GPIO:36 mask:0x1000000000
GPIO:37 mask:0x2000000000
GPIO:38 mask:0x4000000000
GPIO:39 mask:0x8000000000
GPIO:40 mask:0x10000000000
GPIO:41 mask:0x20000000000
GPIO:42 mask:0x40000000000
GPIO:43 mask:0x80000000000
GPIO:44 mask:0x100000000000
```

## Testing GPIO Operations

You can programmatically do operations from your own python code by using the Meshtastic `RemoteHardwareClient` class. See the [Python API](/docs/software/python/cli/installation) documentation for more details.

You can add a simple LED and resistor to validate that the GPIO operations work as expected. Use [this tutorial](https://www.instructables.com/Slide-Switch-With-Arduino-Uno-R3/) as a guide.

### Requirements

- (x2) Meshtastic devices (one device could be on a local computer, and the other one just has to be powered and is the one with the LED to be connected to it)
- (x2) wires (black and yellow; they can be any color but typically black is used for ground)
- (x1) LED
- (x1) 220Ω resistor (somewhat optional, but recommended)
- (x1) Breadboard (optional)

### Preparation

1. Disconnect the remote device from power (battery/usb)
2. Connect the resistor to the longer (positive) lead of the LED and the yellow wire to the other end of the resistor
3. Connect the other end of the yellow wire to a GPIO pin that will not cause any issues (ex: for TLoraV1, we can use GPIO21)
4. Connect the black "ground" wire from the ground pin on the device (ex: for TLoraV1 it is the end pin next to the RST button) to the shorter (negative) lead of the LED
5. Power on the device

### Validation

By default, the pin may be "off" or "on". (It will most likely "off".) See the steps below for running commands. In the example of GPIO21, the mask would be `0x200000`.

![T-Lora v1 with LED on GPIO 21](/img/LED_on_TLoraV1.jpg)

## Using GPIOs from the Python CLI

### Writing a GPIO

```shell title="Example: turning 'on' GPIO4"
meshtastic  --port /dev/ttyUSB0 --gpio-wrb 4 1 --dest 28979058
# Connected to radio
# Writing GPIO mask 0x10 with value 0x10 to !28979058
```

### Reading a GPIO

```shell title="Example: read GPIO4"
meshtastic --port /dev/ttyUSB0 --gpio-rd 0x10 --dest 28979058
# Connected to radio
# Reading GPIO mask 0x10 from !28979058
# GPIO read response gpio_value=16
```

:::note
If the mask and the gpio_value match, then the value is "on". If the gpio_value is 0, then the value is "off".
:::

### Watching for GPIO Changes

```shell title="Example: watching GPIO4 for changes"
meshtastic --port /dev/ttyUSB0 --gpio-watch 0x10 --dest 28979058
# Connected to radio
# Watching GPIO mask 0x10 from !28979058
# Received RemoteHardware typ=GPIOS_CHANGED, gpio_value=16
# Received RemoteHardware typ=GPIOS_CHANGED, gpio_value=0
# Received RemoteHardware typ=GPIOS_CHANGED, gpio_value=16
# < press ctrl-c to exit >
```