If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #10
Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424
Depending on the LED's and the sensitivity of your circuit, use complementary filters eg blue cellophane over the LED's (or just use blue LED's) and red cellophane over the photodiodes. You have to make your output not couple with your input as in any closed system or it will oscillate. Alternatively, reverse your phase ie turn the lights off with proximity which gives negative rather than positive feedback (I think). Neither of these might be practical in your case though.
Registered Member #63
Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425
I worry that the negative feedback could pretty much inhibit the LEDs coming on at all (as I found out with the original circuit with the 2N7000, if the phototransistor could "see" the LEDs at all.
Black IR-transmissive screening.... that sounds like a good idea.
I was going to consider a simple delay circuit, but with sufficiently large arrays, there would still be feedback issues -- you'd get a "wave" of light bouncing back and forth along the array... pretty, but not the interactive result I'm intending.
I guess I'll have to give it a try with dim, crappy LEDs...
The resolution of the array is also causing trouble. If the array consist of only hand-sized sensors, then if you wave a hand-sized object (i.e. a hand) over the top, adjacent sensors will not "see" the illuminated hand. As soon as the object is larger (unless it's totally black) than one element in the LED/sensing array... the others will see the illuminated surface above them.
Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
This is why the future is digital and programmable. When the program does not work you change it and 5 minutes later it all works. A hint to those that still are fairly young, after a certain age it becomes very hard to become a good programmer so sooner is lot better than later.
Multiplexing might work to stop the wrong LEDs affecting the photodiodes.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
motion detection
