The Light Sensor


Soldering a cheap light sensor to the end of a wire so you can mount it on the garden station,or wherever else you want an electric eye.


Supplies:
(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






Step-By-Step

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 this module.

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 breadboard.



about how-to parts contact GardenBot home forum