I will definately try to incorperate this touch sensing in my upcoming project. i have an 15 inch lcd touch screen hooked to a dell laptop and it is mounted to a sheet metal panel i will have loads of features for this unit when complete. it is what i am referring to as my mobile lab
Ok maybe an admin could move the thread somewhere else more appropriate, and as common courtesy add the attribution from whence it was cut from. I've no idea what that attribution would be.
I never said I had completed the project, nor am I the original poster, all I said was I found it an interesting thread.
Well, whenever somebody wants to make this truly interesting by documenting his claims, it won't be too soon, and I won't be holding my breath waiting.
I am amazed. I last contributed to this thread in 2004 and have a pile of hardware that explored the LED as a sensor.
What really appeals to me is using an 8X8 LED matrix to create an X-Y input device. I may get back into that project as the hardware side was completed. I just didn't get into coding the SX28 to create the whole finished product. Maybe it is time to do so, and get this thread back into 'Finished Projects'. (Someone else has done it already with a different processor.)
As an interesting experiment that elucidates (sorry) the physics of the diode, it certainly works with the Stamp.
' {$STAMP BS2e}
' {$PBASIC 2.5}
' led (green or yellow preferred)
' with anode connected to pin dA through 200 ohm resistor
' and cathode connected to pin pK
' program flashes LED at a rate proportional to incident light level
' For light brighter than typical indoor levels, tie a capacitor
' (~100 or 1000 pF) in parallel with the diode.
'
dA PIN 1
dK PIN 0
DO
LOW dK ' brief flash of light
HIGH dA
PAUSE 1
LOW dA ' now reverse bias the diode
HIGH dK
RCTIME dk,1,W1 ' wait for diode capacitance to discharge (faster in brigher light)
LOOP
It makes a decent ambient light sensor. I've used it to automatically turn off the backlight for a transreflective LCD when outdoors. If the user really wants it turned on, they can put their thumb over the sensor.
The X-Y grid (mpeg video) that provided its own light was very clever.
What hornet's nest? PJ, enlighten us. Are you skeptical about the physics per se, or about its practical application as a touch sensor?
Tracy,
The OPs post was baloney and there was no follow-up, it's all very "Roswell".
Others had thus and sundry using devices other than the BS2. Your example is the first to make use of RCTIME, it occurs to me.
Beyond that, yes, the practicality is the rub. When I see widespread adoption in consumer electronics, when it's "that good", then, I guess, it's a take. Is that reasonable?
Fair enough, it will join the hall of lesser fame, alongside the tunnel diode dip meter. Still, it is a good teaching tool, a good toy, a good trick to have available for special designs--Even if it doesn't make it to the commercial mainstream. I don't agree about the baloney though. I take the OP at his word that he had something working and learned something in the process. Ryan Clark at Parallax had a line sensor going, although AFAIK he never got around to writing the planned application note. About that time in 2006, I was playing around with the above RCTIME, and converting that for the Prop was my first Spin program.
Erco, As an interesting experiment that elucidates (sorry) the physics of the diode, it certainly works with the Stamp.
Sorry Tracy, I missed your reply 2-1/2 months ago! If you say it works, I'll def try it and report back.
Interestingly enough, I built a board last night using "someone else's" 18M2 uC just to try out their capacitive touch sensors. Zero components, just metal pads on the PCB. They work quite well after calibration.
Comments
There's nothing from the O.P.
Maybe it could go Bye-Bye?
I for one find the thread interesting and would vote not to delete it.
Somebody did a cut and paste from another site's page.
Do you have it working?
I never said I had completed the project, nor am I the original poster, all I said was I found it an interesting thread.
I think it's all a load.
What really appeals to me is using an 8X8 LED matrix to create an X-Y input device. I may get back into that project as the hardware side was completed. I just didn't get into coding the SX28 to create the whole finished product. Maybe it is time to do so, and get this thread back into 'Finished Projects'. (Someone else has done it already with a different processor.)
As an interesting experiment that elucidates (sorry) the physics of the diode, it certainly works with the Stamp.
' {$STAMP BS2e} ' {$PBASIC 2.5} ' led (green or yellow preferred) ' with anode connected to pin dA through 200 ohm resistor ' and cathode connected to pin pK ' program flashes LED at a rate proportional to incident light level ' For light brighter than typical indoor levels, tie a capacitor ' (~100 or 1000 pF) in parallel with the diode. ' dA PIN 1 dK PIN 0 DO LOW dK ' brief flash of light HIGH dA PAUSE 1 LOW dA ' now reverse bias the diode HIGH dK RCTIME dk,1,W1 ' wait for diode capacitance to discharge (faster in brigher light) LOOPIt makes a decent ambient light sensor. I've used it to automatically turn off the backlight for a transreflective LCD when outdoors. If the user really wants it turned on, they can put their thumb over the sensor.The X-Y grid (mpeg video) that provided its own light was very clever.
What hornet's nest? PJ, enlighten us. Are you skeptical about the physics per se, or about its practical application as a touch sensor?
The OPs post was baloney and there was no follow-up, it's all very "Roswell".
Others had thus and sundry using devices other than the BS2. Your example is the first to make use of RCTIME, it occurs to me.
Beyond that, yes, the practicality is the rub. When I see widespread adoption in consumer electronics, when it's "that good", then, I guess, it's a take. Is that reasonable?
Sorry Tracy, I missed your reply 2-1/2 months ago! If you say it works, I'll def try it and report back.
Interestingly enough, I built a board last night using "someone else's" 18M2 uC just to try out their capacitive touch sensors. Zero components, just metal pads on the PCB. They work quite well after calibration.