Moderators: Dave Moll, Steve Anderson
harry dalek wrote:Well i finished my first go at a finished one the led nipkow..perhaps i should do an Albert and call it the LEDKOW but not using the led part so might be cheating .
.
Steve Anderson wrote:I will be the first to admit I've only skimmed through the previous, but how do you plan to get power, signal (and perhaps) commutation info to these LEDs? Irrespective of their optical performance. Not being negative, just curious...please don't say slip-rings...
Steve A.
AncientBrit wrote:Steve,
I think he's using them as lenses only, back lit.
No actual signal excitation,
Cheers,
Graham
Viewmaster wrote:harry dalek wrote:Well i finished my first go at a finished one the led nipkow..perhaps i should do an Albert and call it the LEDKOW but not using the led part so might be cheating .
.
As LEDs are not used put them last, so KOWLED.......you can led a cow to 12v but you cannot make him glow.
My,my Harry, you certainly do get going when you get going !
Who does all the dusting, cooking, housework and gardening then?
AncientBrit wrote:Not sure how narrow the scan line will appear to the eye.
Most LED lenses diffuse the light from the chip to produce a fairly broad swathe so maybe the scan lines will overlap.
Also a broad "spot" may have an effect on the perceived resolution along the NBTV line.
Regards,
Graham
I was right a while back on the encoder when i was thinking reflective surface and not so reflective is that worked last time ...as i am using no black this time just reflective gold colour of the dvd and the white paper not so reflective ...so the encoder in my case is working like that not so much the black and white idea ,only pain is i have to cut the encoder disk so the reflective part of the dvd is viewable to the IR sensor.
The other thing you could have done, and may want to do in future, is to take your encoder print out to somewhere they can do photocopies. For a few cents you can make enough to last you quite a while. The photo copier toner should work the same as laser printer toner. If you do that, it may be a good idea to just get the one copy first just to make sure. I am sure this won't be the last encoder you make .
Edit: I should point out also that for optimum efficiency the reflective sensor should be perpendicular to the encoder, the pictures seem to indicate that you have it at a bit of an angle.
Having said that I am wondering if your arrangement only works at that angle as I would have thought there would have been significant IR reflection from the gold paint on the disk. I am wondering if it works at an angle because the diffusing characteristic of the paper causes some light to be reflected back to the sensor whereas the non-diffusing characteristic of the gold paint causes the reflected light to continue travelling in the same path thus missing the sensor. Stranger things have happened.
Actually Harry, I wonder if you could do me a favour? As I don't have an ink printer any more I can't do the following experiment myself:
I have to admit I find it amazing that a black (ink) surface would reflect IR back at more-or-less the same intensity as the white surface of the paper.
Being from Missouri I would like to "see" that effect - one way to do it is to video the encoder at the point that the sensor is shining on it with a webcam (or similar). As these cameras are IR sensitive we should see a spot of light that does not diminish in intensity when it is on a black section to when it is on a white section. In fact, if you video it in a dark room that has no source of visible light we should see that the encoder pattern looks all white instead of black and white.
You could also perform the experiment with any black and white print out from your printer and using your TV remote control as the the IR source - in fact that would obviously be much easier.
If you don't have time for that I wonder if you could post me a copy of one of your encoders? Possibly with the Christmas card you were going to send me?
gary wrote:Sorry Harry, I meant a normal encoder - one with black and white segments - not the one with the cutouts - although that would be interesting too - I just want to convince myself that your printer ink is reflective to IR
Users browsing this forum: No registered users and 10 guests