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Pimoroni Grow HAT Mini

Created: 2026-05-31 14:06
Updated: 2026-06-02 17:28

grow_hat_mini.png

I ordered a Pimoroni Grow HAT Mini to water the tomatoes in my greenhouse. When I went to hook it up, I discovered that it needs a few updates to work on Trixie. Here's how I installed the latest dependencies and made some minor tweaks to get it running on the latest Raspberry Pi OS.

Contents

OS Install

Most folks will want to use the Raspberry Pi Imager.

Also check out my related post: Command Line Only Install For Headless Raspberry Pi OS (Trixie).

Install OS Dependencies 

# install deps
sudo apt-get update
sudo apt install -y git           \
                    libfreetype6  \
                    libopenjp2-7  \
                    python3-dev   \
                    python3-numpy \
                    python3-pil   \
                    python3-pip   \
                    python3-setuptools

Download Source Code 

# cd into directory where you want to clone the repo
cd ~/projects

# clone project
git clone https://github.com/pimoroni/grow-python

# cd into repo workspace
cd grow-python

Set Up Python Virtual Environment

Set into your repository workspace and run the following.

# create python virtual environment
python3 -m venv --system-site-packages .venv

# source virtual environment variables
source .venv/bin/activate

# install python package from current directory
pip install -e .

# install dependency
pip install gpiodevice

Enable Devices

Counterintuitively, in the examples below, "0" means enabled.

Run these commands to enable i2c and spi. The commands should produce no output.

# enable i2c and spi
sudo raspi-config nonint do_i2c 0
sudo raspi-config nonint do_spi 0

Now, confirm the devices are enabled. Both these commands should output "0" to indicate enabled.

sudo raspi-config nonint get_i2c
sudo raspi-config nonint get_spi

Now reconfigure the spi0 chip select pin in /boot/firmware/config.txt. If you miss this step, when you run monitor.py, you'll see the error message: lgpio.error: 'GPIO busy'.

# update config.txt
sudo vi /boot/firmware/config.txt
#
# add this to the very bottom of the file (in the [all] section)
dtoverlay=spi0-cs,cs0_pin=14

# reboot
sudo shutdown -r now

Install the Hardware

If the hat isn't already installed, shut down and install it now.

I had to use a bit more pressure than I normally use when installing HATs. The HAT looked pretty shallow, but it ended up seating down further than I expected. It feels very secure and does not move around when I press the buttons on the HAT.

Verify i2c Device Found 

# verify i2c enabled
lsmod | grep i2c
      i2c_dev                12288  0
      i2c_bcm2835            12288  0

# install dependencies
sudo apt install i2c-tools

# check device
sudo i2cdetect -y 1


# this is what you will see if your device is not found

           0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
      00:                         -- -- -- -- -- -- -- --
      10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      70: -- -- -- -- -- -- -- --

# this is what you want to see, everything looks good!

           0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
      00:                         -- -- -- -- -- -- -- --
      10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      20: -- -- -- 23 -- -- -- -- -- -- -- -- -- -- -- --
      30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      70: -- -- -- -- -- -- -- --

Apply Patch for Trixie

Check out my PR here, which contains the updates needed:

You can apply my PR as a patch using the following command. Run this from the root of the grow-python repo:

curl -L https://github.com/pimoroni/grow-python/pull/50.patch | git apply -v

Run the Monitor 

# re-activate virtual environment
source ~/projects/grow-python/.venv/bin/activate

# run monitor
cd ~/projects/grow-python/examples
python monitor.py

# run directly without activating
~/projects/grow-python/.venv/bin/python ~/projects/grow-python/examples/monitor.py

Next Steps

Check out the Pimoroni guides: