Soldering a cheap light
sensor to the end of a wire so you can mount it
on the garden
,or wherever else you want an electric eye.
(see the parts page)
- small photocell
- a 10K resistor
- a short piece of heat shrink tubing (glue lined) and heat gun
- soldering iron and solder
- lead wires
||Here we have two
lead wires that are stripped and ready to go. We also have the small
photocell which still needs to have its legs clipped down to short
stubs to match the lead wires.
||Now the photocell
is soldered onto the end of the lead wires. Next, cut two short pieces
of heat-shrink to insulate each leg.
||And finally, the
finished light sensor. Simple, but very durable and reliable.
You can now just easily strap this to the garden station, or wherever
you want a light sensor.
Note that an indirect reading is best.
The Local Circuit
Here's the diagram for the local circuit portion of
The circuit is mainly a voltage divider - the soil moisture sensor is
one half and the 10K resistor is the other half.
There is also a noise filter - the 0.1uF capacitor going to ground. And
of course, an output so the Arduino can take a sensor reading.
And here is what that circuit might look like on your