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This is for a high school project that I'm doing. The sensor should be able to detect the movement of a moving inanimate object and convert into electrical energy, and be fairly cheap to buy.
I have looked into a few sensors but most of them seem to be geared towards detecting HUMAN movement, eg. PIR sensors. I am looking for the type of sensor that is able to detect non-human movement at close range (about 1/2 metres). Any suggestions?
There are a range of solutions based on the type of environment you are gonna implement your system;
So I will list the possible solutions and the respective best possible implementation conditions.
You can use IR sensors to detect motion. Given your sensors are setup in a controlled environment where the ambient lighting is consistent, you can setup IR to read ranges from a given distance. For example lets say you object is at 1 m from the sensor; your MCU can constantly read the voltage drop from IR sensor and detect 'motion' when there is change in these voltage readings. This only works if your sensors are stationary relative to your detecting object. This is a very cheap solution. Can easily program using Arduino. You can even use code already written from other users.
Using an ultrasound module. This works by sending a 'ping' and
listens for the echo. Motion can be detected by monitoring the width
of the 'echo' pulse. This solution doesn't not require a controlled
lighting environment unlike IR. But on the flip side, ultrasound
signals are not directional like IR; and hence your system maybe
prone to noise from other reflected 'echo' pulses off target. But
this can be implemented successfully by properly thresholding your
signals. This too can be implemented using Arduino easily. Check PING
example in Arduino IDE. This requires your system to be stable
relative to your target.
As mentioned earlier, camera is another solution. It could
implemented intelligently regardless whether your system is
stationery relative to your target. But this requires you to have
some kind computer vision/programming background. Since you mentioned
you are from high school, I presume this will be a bit challenging
for you. But you always try. OpenCV, and Matlab CV toolbox are a good
starting point. But this solution is relatively expensive. Camera is
relatively expensive compared to IR and Ultrasound. And if you are
looking for a embedded solution, you need a much powerful MCU than an
Arduino to deploy your project.
Cheers and good luck
