Hello all,

I'm new to the world of Arduino and thoroughly enjoying things so far. I decided to go a little further with my experiments, and try hooking up a phototransistor.

The thing I'm a little unclear about though, is exactly how I'd go about hooking that up to the Arduino, and interpreting the output (I just tried to paste a link to the product into this post, but the forum software won't let me do it until I've made 'one normal post', so I'll follow this post up immediately with the link to the sensor!)

I've done a bit of digging around and I'm not really sure how to go about hooking it up and interpreting the readings with the Arduino just yet.

Would anyone be able to offer some advice/pointers?

Many thanks,

/Rich.

I ordered this 1 - still waiting
Teh Hex Pummer
http://www.solarbotics.com/products/k_hp/

Quote:

Or you can use the internal pull up resistors
You will need to set the pinMode to input anyway:
 pinMode(pin, INPUT);           // set pin to input
if you write a HIGH value after the pin is set for input then the internal pull-up resistor will be connected:
digitalWrite(pin, HIGH);       // turn on pullup resistor
This saves you connecting an external 10k resistor to the pin.

Quote:

Nice tip

Hi all,

The schematic on the Maplin site is indeed - pants.

Thanks to everyone so far for all your help. I'll give this a go later this evening and post my results.

Again, thanks for the speedy replies!

/Rich

Quote:


Ground should wire to the cathode lead of the photo diode. The anode lead of the diode should wire to the 10k resistor. The other end of the resistor should wire to +5vdc. Digital pin 7 should wire to the junction of the diode anode and 10K resistor.

Lefty

Hi Grumpy_Mike,

That's exactly what I needed - thank you. Now, when the photo transistor is 'open' the input is HIGH. When it is 'reflecting' the input is LOW. Does that sound about right?

Thanks,

/Rich