Hello there,
I am currently taking part in a group project which involves building a line following robot. I have been taking charge of sensors, and so far I have the following circuit working properly and reacting very well to passing over black lines on the ground.
Apologies for the quality of the drawing, I just knocked it up in paint quickly. D1 is an IR LED and D2 is just a red LED for testing. PT is a phototransistor (which actually responds to both natural and infrared light, however in the original design a IR sensing photodiode was used hence the IR LED).
The Op-amp being used is the LM324, and the reason for this is the quad inputs/outputs, as there will obviously be more than one sensor to operate the robot.
But anyway to my predicament, it was suggested to me that I attempt to configure this circuit to that of a schmitt trigger. Looking through the 324 datasheet, there is even an example of adding a slight bit of hysteresis to the circuit. However I am unsure how to implement it in this particular circuit, or calculate any values of positive feedback resistor with the sensor and the phototransistor. I feel like having the 10k pot may also have an impact on this, although I may of course be wrong.
So if anyone has anyone hints/tips to help me that would be greatly appreciated. Also please do tell me whether you think this is even a good idea to be going for, or if it is unnecessary. This is my first real electronics project and some of the decisions you have to make turn out to be more instrumental than I ever thought they would.
Thanks for any help,
LearnMeElectricals
I am currently taking part in a group project which involves building a line following robot. I have been taking charge of sensors, and so far I have the following circuit working properly and reacting very well to passing over black lines on the ground.
Apologies for the quality of the drawing, I just knocked it up in paint quickly. D1 is an IR LED and D2 is just a red LED for testing. PT is a phototransistor (which actually responds to both natural and infrared light, however in the original design a IR sensing photodiode was used hence the IR LED).
The Op-amp being used is the LM324, and the reason for this is the quad inputs/outputs, as there will obviously be more than one sensor to operate the robot.
But anyway to my predicament, it was suggested to me that I attempt to configure this circuit to that of a schmitt trigger. Looking through the 324 datasheet, there is even an example of adding a slight bit of hysteresis to the circuit. However I am unsure how to implement it in this particular circuit, or calculate any values of positive feedback resistor with the sensor and the phototransistor. I feel like having the 10k pot may also have an impact on this, although I may of course be wrong.
So if anyone has anyone hints/tips to help me that would be greatly appreciated. Also please do tell me whether you think this is even a good idea to be going for, or if it is unnecessary. This is my first real electronics project and some of the decisions you have to make turn out to be more instrumental than I ever thought they would.
Thanks for any help,
LearnMeElectricals