If you know nothing about robotic, i’m affraid you’ll have to start a lot simplier…
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Connect an ultrasonic rangefinder to a wheelwheelchair (and have the wheelchair to act consequently) will be more than just hook up the sensor to the chair…
Correct. Start with the Correct. Start with the "Start here" robot to get some knowledge on motors, sensors and microcontroller. Then move on to controlling your wheelchair.