Hey everybody, I want to measure the velocity on my RC car. I was thinking about using an hall effect sensor and mounting magnets in the wheel of my RC car, but I thought it would be pretty hard to do it this way. Instead, I want to use a photocollector that I already have and mount it to my RC Car. (here is the datasheet btw http://sensing.honeywell.com/index.cfm/ci_id/141116/la_id/1/document/1/re_id/0 )
Basically I found a metal shaft that is attached to the gear of my motor. I want to put a metal ring and mount it to this shaft. I then am planning on cutting a slit out of the ring and mounting the photosensor around the ring so that the photosensor can "count" each time the ring makes a revolution.
My circuit that I am using consists of one side of a 10k resistor tied to 5v and the other side tied to the collector of the phototransistor. The emitter is tied to ground. I then take the collector voltage and send it to a 74ls14 to get a digital output.
I have just tested this circuit with a piece of paper and everything seems to work well, I get 5V when the paper is present and 0 V when the paper is gone, but I am concerned that it will not be able to switch fast enough when the motor is at high RPMs. Does anybody know if this circuit is feasible at a high RPM setting? I didn't see anything in the datasheet about anything involving any sort of response time, so I'm a bit concerned about this....
Any help would be appreciated,
Thanks,
Joey
Basically I found a metal shaft that is attached to the gear of my motor. I want to put a metal ring and mount it to this shaft. I then am planning on cutting a slit out of the ring and mounting the photosensor around the ring so that the photosensor can "count" each time the ring makes a revolution.
My circuit that I am using consists of one side of a 10k resistor tied to 5v and the other side tied to the collector of the phototransistor. The emitter is tied to ground. I then take the collector voltage and send it to a 74ls14 to get a digital output.
I have just tested this circuit with a piece of paper and everything seems to work well, I get 5V when the paper is present and 0 V when the paper is gone, but I am concerned that it will not be able to switch fast enough when the motor is at high RPMs. Does anybody know if this circuit is feasible at a high RPM setting? I didn't see anything in the datasheet about anything involving any sort of response time, so I'm a bit concerned about this....
Any help would be appreciated,
Thanks,
Joey