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This guide provides a list of common issues and instructions for how to troubleshoot it.
Most errors arise from incorrectly placed or loose wires in your circuit. If your sensor isn’t working, try these basic steps first:
1. Check that all wires are actually in the correct position on the breadboard. Breadboard sockets are small so it is easy to make the mistake of inserting wires into the wrong row. Check each connection one by one.
2. If your connections are correct, check to see if any are loose. Sometimes a wire is not pushed completely into place and so the connection in the circuit is not complete. Check for loose connections and tighten them if you find them.
3. Try unplugging the power from your sensor (either the red battery wire or eject from computer power), let your sensor rest for a few seconds and then plug the power back in.
Sometimes it can be difficult to identify exactly which connections might be an issue, so the guide below identifies some common errors and how to fix them.
If the issue you are encountering is not listed below, feel free to post your issue in detail along with any helpful images to our discussion forum.
Introductory Sensor Activities
Problem: The LED in the simple circuit from Activity 1.2 does not light up.
Solution: This most commonly occurs if the LED is not getting powered correctly because it is positioned correctly in the breadboard. Check your connections. The LED has a long end (positive) and a short end (negative). You may have swapped the position of these. Try reversing the position of your LED. This occurs because the LED is not getting power.
Sensor Setup (Temperature, Light or Distance)
Problem: Squares on the LCD screen
Solution: This occurs when there is a loss of power or incorrect ground while the LCD was already on. Ensure jumpers are inserted completely and contacts are clean. Reset the board (soft reset on computer, reset button on microcontroller), or if you are already in the process of collecting samples, press the measure button.
Problem: LCD is light up but no text is displayed.
Solution: The SDA and SCL connections to the LCD are switched or not connected correctly. Double check those specific connections.
Problem: Distance sensor measurement displays -0.1cm and never changes.
Solution: This occurs because there is no information being returned from the sensor, either as a result of insufficient power or wrong connections. Double check that wire positions are correct. If using the battery, charge the battery fully. If using computer power, move the VCC wire for the distance sensor from the positive power rail to a breadboard socket next the USB pin on the microcontroller.