Let's Make Robots!

Don't fear the 50/60 Hz noise - Use it

I am sad to say that I do not get much time to build any robots these days.. However, every now & then I get a few moments in my workshop.

Thanks to OddBot I got myself some phototransistors a while back, and now I had some time to play. I was thinking of making 2 robots send little signals to each other via a light beam.

Unfortunatly it's winter time in Denmark, and so I had to work under indoor light bulbs. And as you may know; Working with pulsating light under a such can be a pain!

So I thought.. hey - if these 50 Hz are so over all dominant, and the darn phototransistor, hooked up to a Picaxe spinning 16 MhZ is so happy to pick up this "noise".. well then, why not make use of it?

So I just used a phototransistor, and wrote a few lines of code that I thought would be really "bad" for what used to be a problem.. and ended up getting myself a new sensor with an amazing thin beam, working at up to 40 CM's - as long as the target is hit by a light from an indoor lamp :)

I haven't done much testing on it, have little time, and want to do something else.. however, thought it was a quite funny thought; Let the "lightbulbs" work as a "sub-carrier" instead of trying to avoid them :)Perhaps one of you out there have more time, and wants to pick this up?


Readadc10 (read analouge in with high resolution), have a light bulb on, and read the numbers that you are getting. They are extremely steady, so the rest should give itself - the sensor could be programmed any way you'd like..


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I think it means do up your zip



One way or another





Zip up or down has no effect on our battle of wills. If I must "fasten my helmet" (asumming prepare for war) as Fritz said it does not translate well. Then Annette and I must battle to victory in a Thread Created by Frits and judged by the LMR  membership!

"Fasten your helmet" is more like "Shape up, dude", get into the game, comon, get real, hello!


Oh well, I'm not an Odd Bot for nothing then :]

It would help a lot if you could give us a datasheet or at least a part number of the phototransistor you are using. The narrow beam is probably due to it's lens. That also seemed quite sensitive but what range of values are you getting from the ADC?

Hi im Frits' wife Anette. i understand that you think i should go bake a cake!? anyway frits told me to read the part number as he is taking care of our daughter. and he is partly blind.. 

the part number is: BPY 62-2 9218

and for you other question: from about 1020 down to about 950.


regards, anette.

Fasten your Helmet? is that a Vikkin term (AKA be prepared for battle! I'm gonna kick your ass!!!) or should I translate that as I have biten off more than I can Chew and be ready for defeat????? LOL

I like your attitude lots!  Thanks for the info. You remind me of a friend of mine, I'll battle you any time :P

If I'm a nutter, are you the fruit? E.g. fruit and nut cakes?


I was wondering if you had given up on phototransistors. I'm glad your having some fun with them and being truly creative by finding new uses for them.

Why is Rik in the circuit? :p    He should be making his own robots.

Hey, thanks for teaching me about them photo-thingeys :)

And that would be R (or resistor) and 1K for 3 330 resistors in a row!

but the photo didn't translate well :D