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 #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1715
Anyone know if black fur might be reasonably light in near-IR or near-UV light?
My cat loves to drink water as it pours from a hose or watering can. I want to make an outdoor water fountain for him. The sanitary, low-tech way is fed from a water pipe, with spring-return valve operated by a trained animal. The foolishly fancy way uses an electronically activated valve or pump. Could be solar-powered, since the critters out at night here are generally undesirable.
Registered Member #509
Joined: Sat Feb 10 2007, 07:02AM
Location:
Posts: 329
Time to get the cat microchipped with an RFID tag "incase it gets lost" (or thats the story if there is a SWMBO to justify it to) RFID coil with a decent range, microcontroller, solenoid, etc etc, and no more worries about misbehaving optics.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Here is an experiment you might try:
While cat is snoozing in the sun, take his temperature with an IR thermometer.
Repeat experiment after painting cat with emissivity spray.
From the difference in the two readings, you ought to be able to work out something.
I've seen solar powered outdoor lights with PIR sensors, which work using body heat in the far infrared. It shouldn't be too hard to modify one of these so it operates a valve.
Or on the microchipping theme, but cheaper and less invasive, attach a small RFID tag to the cat's collar. I think there is a commercial device like that, an electronic cat flap that only opens for your cat.
Registered Member #3324
Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276
yeh, use a pressure plate and a light detector, when its night it could dope the water with cyanide, removing the night-critter problem, 2 birds with one stone --------- but in all seriousness, id go with Rich's idea or Steves idea
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
Just add an RFID tag to its flea collar.
Many moons ago, I had a problem with the neighbourhood getting into the house, so put 3 turns of wire and a 10nF capacitor into epoxy, carved it into a discreet shape to hang from the collar, and tested it to find out whjere the resonance was. Then it's a simple matter to detect its presence up to a cat head's length away by unbalancing a basic metal-detector bridge running at that frequency. I should have checked the frequency before I potted it, as it ended up in the middle of the AM band. But my detection bridge was very low power, and near field, and hey, nobody in my neighbourhood listened to AM anyway. You put the detect gubbins just below the water outlet, the cat will do the close positioning of the RFID tag for you.
The toughest bit of my project was getting a solenoid to unlock the cat flap in a robust way that couldn't be burgled by the incredibly clever Burmese living next door, or trap her once she'd got a claw under to open it the "wrong" way. Your toughest job might be waterproofing the detector?
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1715
For those who haven't seen the image recognition cat door: Pretty elaborate, but it may help to promote the creator's consulting services. It does not depend on any collar, cat modification, or training. Follow-up pages show that it can distinguish the individual profiles of 2 cats that succeeded Flo.
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.
Reflectivity of black fur?
