Hi,
I'm doing a project To design and build a follower robot that is supposed to follow a jogger outside and carry their things for them on their run. I have the mechanics down, motors, loading bear, etc., but I'm having trouble with the "following" aspect of this robot. The robot is controlled by an Arduino MEGA 2560 and my plan for the making it follow was to put some kind of emitter on the runner, on like a belt or something, and then mount a receiver on a servo on the front of the robot set to sweep for the emitter and steer the robot based on the angle of the servo when the reciever detects the emitter. Initially I had planned to do this with IR LED's and an IR phototransister, but quickly found out my set up was only getting me about 3 feet of detection with like no cone of view and did not work in sunlight. Now I have a couple of ultrasonic transducers I got form Jameco (http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_139492_-1) because I have seen some stuff where ultra sonic detection can be done with a good 10-15 ft range, a decent cone of view, and due to 40kHz operating frequency pretty interference immune.
I Have a good transmitter circuit using a 555 timer that is powered by a 9 volt that will be easy to string down and put into a little project box that could be put on a person (although I have no Idea if the transducer is actually emitting the sound wave since I obviously can't hear it and don't know an good way of seeing if it's working). The trouble I'm having is making a good receiver circuit. I want to do something like this (http://www.ecelab.com/circuit-ultrasonic-r.htm) because I like the digital output form the NE567, but I don't trust the LM741 at 40kHz.
I can make my own circuit using passive BJT amplifiers and a comparator or whatever, but I don't know the order of magnitude of the output of the transducer being used as a receiver. I know the transmitter is being powered by 40kHz 0-5V square wave (from my circuit which I don't know how to post, but trust me that's what it's doing) and I know the receiver is supposed to produce a 40kHz sine wave, but I got nothing on the order of the amplitude.
Also kind of as a foot note, I am a mechanical engineering student, so my electrical knowledge... leaves a little to be desired.
I'm doing a project To design and build a follower robot that is supposed to follow a jogger outside and carry their things for them on their run. I have the mechanics down, motors, loading bear, etc., but I'm having trouble with the "following" aspect of this robot. The robot is controlled by an Arduino MEGA 2560 and my plan for the making it follow was to put some kind of emitter on the runner, on like a belt or something, and then mount a receiver on a servo on the front of the robot set to sweep for the emitter and steer the robot based on the angle of the servo when the reciever detects the emitter. Initially I had planned to do this with IR LED's and an IR phototransister, but quickly found out my set up was only getting me about 3 feet of detection with like no cone of view and did not work in sunlight. Now I have a couple of ultrasonic transducers I got form Jameco (http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_139492_-1) because I have seen some stuff where ultra sonic detection can be done with a good 10-15 ft range, a decent cone of view, and due to 40kHz operating frequency pretty interference immune.
I Have a good transmitter circuit using a 555 timer that is powered by a 9 volt that will be easy to string down and put into a little project box that could be put on a person (although I have no Idea if the transducer is actually emitting the sound wave since I obviously can't hear it and don't know an good way of seeing if it's working). The trouble I'm having is making a good receiver circuit. I want to do something like this (http://www.ecelab.com/circuit-ultrasonic-r.htm) because I like the digital output form the NE567, but I don't trust the LM741 at 40kHz.
I can make my own circuit using passive BJT amplifiers and a comparator or whatever, but I don't know the order of magnitude of the output of the transducer being used as a receiver. I know the transmitter is being powered by 40kHz 0-5V square wave (from my circuit which I don't know how to post, but trust me that's what it's doing) and I know the receiver is supposed to produce a 40kHz sine wave, but I got nothing on the order of the amplitude.
Also kind of as a foot note, I am a mechanical engineering student, so my electrical knowledge... leaves a little to be desired.
