MONK MAKES 46177 ARDUINO Plant Monitor Instruction Manual
- June 4, 2024
- MONK MAKES
Table of Contents
46177 ARDUINO Plant Monitor
Instruction Manual
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.
ARDUINO
Warning: The Plant Monitor is designed to operate at 3.3V, not the 5V that
some Arduinos such as the Arduino Uno operates at. So, never power the Plant
Monitor with 5V and make sure that none of its input pins receive more than
3.3V. To connect a 5V Arduino, such as the Arduino Uno or Leonardo you will
need to use a level converter or an (as we have here) a 1kΩ resistor to limit
the current flowing from the 5V Soft Serial transmit pin of the Arduino (pin
11) to the 3.3V RX_IN pin of the Plant Monitor.
Here’s what this looks like, a solderless breadboard is used to hold the
resistor (in the middle of the breadboard), male to male jumper wires to
connect the Arduino to the breadboard, and female to male jumper wires to
connect the Plant Monitor to the breadboard. The connections are as follows:
- GND on the Arduino to GND on the Plant Monitor
- 3V on the Arduino to 3V on the Plant Monitor
- Pin 10 on the Arduino to TX_OUT on the Plant Monitor
- Pin 11 on the Arduino to RX_IN on the Plant Monitor via a 1kΩ resistor.
Note that the resistor is not needed for a 3V Arduino.
Once it’s all connected, you can install the Arduino library for
the PlantMonitor by going to https://github.com/monkmakes/mm_plant_monitor,
and then from the Code menu, select Download ZIP.
Now open the Arduino IDE and from the Sketch menu select the
option to Add .ZIP Library and navigate to the ZIP file you just
downloaded.
As well as installing the library, this will also
fetch an example program that you will find in the Examples sub-menu of the
File menu, under the category Examples from Custom Libraries.
Upload the example called Simple to your Arduino and then open
the Serial Monitor. Here, you will see a series of readings. You can also turn
the Plant Monitor’s LED on and off from the Serial Monitor by sending serial
commands. Type L in the send area of the Serial Monitor and then press the
Send button to turn the LED on, and l (lower-case L) to turn the LED off.
Here is the code for this example:
The library uses another Arduino library called
SoftSerial to communicate with the Plant Monitor. This can carry out serial
communication on any of the Arduino pins. So, when an instance of PlantMonitor
called pm is created, the pins to be used to communicate to the Plant Monitor
hardware are specified (in this case, 10 and 11). If you like, you can change
10 and 11 for other pins. The main loop checks for incoming messages of L or l
from you to turn the LED on or off respectively, using the pm.ledOn or
pm.ledOff commands. Getting readings from the PlantMonitor takes place in the
report function that writes out all the readings to the Arduino IDE’s Serial
Monitor.
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 am connecting using the serial interface, and 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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