Cover by Patrick Di Justo, Emily Gertz

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Make the Gadget

To make this device, we’ll start by constructing the probe that you’ll dip into water samples to get a conductivity reading—which we created by repurposing a binding post (Radio Shack catalog #274-718) typically used in home audio/video and ham radio electronics. It may seem like a complicated build on first glance, because there are several steps involved. But it’s mostly a straightforward matter of connecting wires to the binding post—as you can see in the photo of the finished probe.

Parts

  1. Arduino
  2. Breadboard
  3. 10K resistor
  4. 8-ohm speaker
  5. 4Char display
  6. Chassis-mount dual female binding post (RadioShack catalog #274-718)
  7. Jumper wires in various colors
  8. Several feet of insulated solid core wire
  9. Small piece of aluminum ...

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