I agree, Odd…
I have just re-read the post a couple times and man, even with my total lack of knowledge on the subject I think I could actually get this going. I mean, with no exterior help. --Not that I still couldn’t use it…
it does sound interesting,
it does sound interesting, just need to research more on the pll aspect of it.
and google is your friend…
http://www.geocities.com/lemagicien_2000/elecpage/irvis/irvis.html
I got it…
Well, I skipped the 556 and instead used the PWM and a simple 1ms pause on and off for the other cycle. I am gettng results.
So far, I am looking at about a 18" range and a limited range of numbers coming in. Never the less, it is indeed showing a number proportional to the distance of a white piece of paper held in front of the sensor. I’m going to keep doing some tweaking but proof of concept is indeed there. In addition, I am using a 08m so if this turns out to be a usable system, the evenual PCB should be nice and compact --Servo mountable.
cant wait for more
I like 08Ms! SHARPs … boooh… go PWM!
For greater range, you might
For greater range, you might try driving the LED closer to it’s edge of specs.
unfortunatly…
I am. I am running 2 in parallel with no resistor! No, I think it has to do with phase timing. I am still a little wishy-washy on the concept, but basiclly there are 2 loops of cycles overlapping eachother. A 38kz signal so the sensor works and a 1khz gate on top of that. I am using pulsin on a second picaxe for testing and I discovered that my limited range of numbers coming in is due to the fact that they are getting too big and too little and “looping” -i.e. if it is a byte variable I am using and the number is bigger than 255 it loops back to 0. I think this should just be a matter of playing with the 1000kc part of things to get that final pulse width into somthing more middle-of-the-road. Again, this does indeed work. I think the next step is to add a pot or two so I can fine adjust on the fly.
If you are running the IR
If you are running the IR LEDs off a PICAxe pin delivering PWM, then you are not driving them to the edge. The PIC will only output about 25 mA per pin. If you are driving the LEDs through a line driver like the ULN2803 with it’s own power, then you might be pretty close, even overdriving since those outputs are capable of delivering more current.
That is a very good call.
I hadn’t thought of that… Why didn’t I? And you are right about the limited current allowed to run directly through a picaxe output. Transistors, here I come.