Datasheet

Layout and
Dimensions:
Connecting a BBC micro:bit:
The board has been designed so that the
BBC micro:bit can be bolted on using 3 x M3
nuts and 3 x M3 screws. Place the screws
through the P1, 3V and GND holes of the
PCB and BBC micro:bit, then use the M3
nuts to fasten together on the back of BBC
micro:bit.
Alternatively croc-clips can be used to
connect between the Prong and the BBC
micro:bit.
If using the Mi:Power board then
additionally connecting P0 means the BBC
micro:bit can sound an alarm if the soil
becomes too dry.
Prong : A soil moisture sensor for the BBC micro:bit
www.kitronik.co.uk/5647
Introduction: Prong is a sensor board that can be directly mounted to a BBC
micro:bit to monitor the moisture present in soil. The two conductive tines are
placed into the soil. Any water or moisture in the soil will conduct to give an
analogue voltage that can be read by the BBC micro:bit.
Power Supply:
Prong is powered from the 3V supply of the BBC micro:bit.
Use either the USB or JST connector on the BBC micro:bit to power the circuit.
Prong and the BBC micro:bit can also be powered from the Mi:Power board
(
www.kitronik.co.uk/5610) to create a compact stand alone unit.
Voltage signal:
To determine the moisture level, the signal is brought out to Pin 1 on the BBC
micro:bit as an analogue voltage The voltage will range between 0V (dry) and 3V
(wet).
The board is 1.6mm thick
Software:
This simple example shows a happy
face when the soil is damp, and a
sad face when it is dry. The pause is
used to space readings out.
3 x M3 connection pads for
BBC micro:bit
68mm
Drill holes spaced for
depth measurements
(3 hole marker is 5mm
1 hole marker
between is 2.5mm)
53 mm
42.5mm