Hello to all the Raspberry Pi users out there!
Hopefully some of you have completed the laser tripwire project which is featured on the official Raspberry Pi website.
I completed this project and got it working, but the tripwire response time is a little slow for the project I’m working on.
I’m building a sport timer for a dog sport called ‘Flyball’. It would take a while to explain it so if you’re interested it’d be best to either Google it or watch a Flyball race on a YouTube video.
From what I’ve been reading online a photo diode or a photo transistor would have a much faster response time (in the nano seconds) compared to a light-dependent resistor.
My question:- how do I safely connect a photo diode or photo transistor to the Pi without frying it? Can anyone recommend parts to do this?
What resistors (if any) would I need… The LDR has no additional resistors, just a 1uF capacitor connected to it in series. As I am new to electronics, can anyone direct me on where to learn about resistors… understanding the ratings and the colour bands, and HOW to calculate what resistor you would need for a Raspberry Pi circuit (Would I be correct in assuming a GPIO pin is 3.3volts? I don’t mean the constant power 5volt and 3.3volt pins either)
Can anybody (hopefully the staff of Core Electronics) recommend the parts needed?
Final bit of information:- the laser emitter I’m using is a diunotech red light emitter. It has a wavelength of 650nm and its output power is <1mW