MONK MAKES 105182 RASPBERRY PI Plant Monitor Instructions
- June 4, 2024
- MONK MAKES
Table of Contents
105182 RASPBERRY PI Plant Monitor
Instructions
WARNING
Only the prong of the Plant Monitor below the white line should be allowed to get wet. If the top of the board gets wet, disconnect it from everything, dry it using a paper towel and then leave it the throughly dry out before trying to use it again.
INTRODUCTION
The MonkMakes Plant Monitor measures soil moisture, temperature, and relative humidity. This board is compatible with the BBC micro: bit, Raspberry Pi, and most microcontroller boards.
- Superior capacitative sensor (no electrical contact with soil)
- Alligator/crocodile clip rings (for use with BBC micro: bit and Adafruit Clue etc.
- Ready soldered header pins for Arduino and other microcontroller boards.
- Easy to use UART serial interface
- Additional analog output for moisture only
- Built-in RGB LED (switchable)
USING THE PLANT MONITOR
The plant monitor should be placed as shown below.
The front side of the prong should be
as close to the edge of the pot as possible.
The sensing all takes place from the far side of the prong.
The electronics should be facing out of the pot and the prong of the Plant
Monitor pushed into the dirt as far as the white line (but no deeper).
It’s a good idea to attach the wires you are going to use to connect to the
Plant Monitor before positioning it in the plant pot.
Once powered up, the plant monitor will immediately start displaying the level
of wetness using the built-in LED. Red means dry, and green means wet. Before
you put the Plant Monitor in the pot, try gripping the prong in your hand and
the moisture of your body should be enough to alter the LED’s color.
RASPBERRY PI
Connect your Raspberry Pi to the Plant Monitor using female-to-female jumper
wires as shown below:
The connections are:
- GND to GND
- 3.3V on the Raspberry Pi to 3V on the Plant Monitor
- 14 TXD on the Raspberry Pi to RX_IN on the Plant Monitor
- 15 RXD on the Raspberry Pi to TX_OUT on the Plant Monitor
WARNING: Do not connect this board to the 5V pin of the Raspberry Pi. The
board is designed to operate at 3.3V and a 5V supply is likely to destroy it.
Since the Raspberry Pi does not have analog inputs, then the only interface
option is to use the serial UART interface. This interface has to be enabled
on the Raspberry Pi from the Raspberry Pi Configuration tool that you will
find in the Preferences section of the Start menu.
Enable the Serial Port and Disable
the Serial Console. You may be prompted to restart your Pi for these changes
to take effect.
To download the example programs for the Plant Monitor open a terminal window
and enter the command:
$ git clone https://github.com/monkmakes/pmon.git
This will download all the example programs for various different platforms
into a folder called pmon, so change to the right directory for the Raspberry
Pi examples by entering the command:
$ cd pmon/raspberry_pi
Before you can run the examples, you will need to install the GUIZero library
with the command:
$ pip3 install guizero
You can now run the examples. The first example 01_meter.py displays the
wetness level, temperature, and humidity level. Run it using the command
below.
$ python3 01_meter.py
.. and the following window should appear.
Try holding the prong of the
moisture meter and you should see the wetness % rise.
Similarly putting your finger over the metal box on the Plant Monitor that is
the temperature and humidity sensor will change both readings.
The second example (02_data_logger.py) is a data logger that records all three
values periodically and put them into a file that you can then import into a
spreadsheet.
Run the program as shown below and collect some data. You might like to put
the Plant Monitor into a plant pot (see page 4) and record readings every
minute for 24 hours (but perhaps start with a smaller set of data).
When you have got enough data, CTRL-c
the program. If you don’t have a spreadsheet installed on your Raspberry Pi,
install LibreOffice using the Recommended Software tool in the Preferences
section of the Start menu. Run LibreCalc and then import the file of data.
You can draw a chart of the data by
selecting it (including the headings) and then inserting a Chart. Pick a chart
type of XY.
TROUBLESHOOTING
Problem: When I first connect power to the PlantMonitor, the LED cycles
through colors. Is this normal?
Solution: Yes, this is the Plant Monitor doing a self-test as it starts
up.
Problem: The LED on the Plant Monitor does not light at all.
Solution: Check the power connections to the Plant Monitor. Alligator
leads and jumper wires can become faulty. Try changing the leads.
Problem: I get wetness readings, but the humidity and temperature
readings are wrong and not changing.
Solution: You may have inadvertently powered your Plant Monitor from 5V
rather than 3V. This may have destroyed the temperature and humidity sensor.
SUPPORT
You can find the Product’s information page here: https://monkmakes.com/pmon
including a datasheet for the product.
If you need further support, please email
support@monkmakes.com.
MONK MAKES
As well to this kit, MonkMakes makes all sorts of kits and gadgets to help
with your electronics projects. Find out more, as well as where to buy here:
https://monkmakes.com you can also follow MonkMakes on Twitter @monkmakes.
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