I want to meassure the speed of a little model car, so i wrote a Programm (Picture is attached) which reads the output from my arduino and plots the values.
First i wanted to use LDR´s but they are to slow. Now I want to use photodiodes, but i dont know how to use. In the Arduino Playground i spotted that you can use them like LDR´s but before i order them i rather ask if its right. And are this Photodiodes good for me: http://tinyurl.com/d7p48y5
Can I built this (and will it work :D). Picture is attached.
Thanks
DJburner
P.S.: Sry for my very bad english, im from germany
Photodiodes are typically used where very high speed is required. In your application, a phototransistor would be more suitable, because it is much more sensitive than a photodiode, but still much faster than a LDR.
"a phototransistor would be more suitable, because it is much more sensitive than a photodiode,"
Sorry, a photodiode better way to go. The phototransistor is essentially a slow photodiode with much more capacitance.
But heck, either will work for a simple light interrupter where response time not an issue. But a PD with an op-amp
in transimpedance circuit is the standard way to go.
And he doesn't need a laser, any old led will work.