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 #62109
Joined: Sun Jan 28 2018, 10:00PM
Location: Porto Alegre
Posts: 56
Hi. I have been observing some curious stuff in some trees here. The branches which take sun all day, "pop" a lot of new branches. So I was thinking about some shape of lens that would make the sun light hit always a same spot on the tree during almost all day. But then I remembered that concentrating light this way, I will just make the tree light up like a torch. I think I need a lens that gets light from various directions and make it come strait from the other side. But without focusing it too much. Just a little more intense than normal sun light.
Registered Member #62109
Joined: Sun Jan 28 2018, 10:00PM
Location: Porto Alegre
Posts: 56
That is what I need. Well the sun is too far, so I can't use the second option. But I have seen people using fresnel lenses to burn things or to cook food. Maybe if I turn the lens around? I'm not sure if if would work the same way on both sides since I don't have one here to test. Thanks for the help.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Andre... all you need is some clear plastic like 20 mil thick and a hoop and some kind of stand.
All you do is attach the plastic sheet to the hoop loosely and put it up on a stand. Then you fill the plastic with water and adjust for how much magnification you want, then use a large flat mirror to direct the light.
When you get bored with that, you can use the "lens" to burn stuff, just remember to wear shades or you'll go blind.
Registered Member #62109
Joined: Sun Jan 28 2018, 10:00PM
Location: Porto Alegre
Posts: 56
Hmmmm, I saw that in these survivor programs on TV. I will try to build one. Oh I did some burning already when I was a kid, but never wore the shades.
I will make a little one and then I come back here if it works. 5cm or 2 inches in diameter. Thank you.
Registered Member #62109
Joined: Sun Jan 28 2018, 10:00PM
Location: Porto Alegre
Posts: 56
Hi Conundrum, I just realised I can't find any of these around here to buy. I will try first with some cheap magnifying glass and also the water lens. If it works I may buy something on the internet.
Thanks Sulaiman, maybe I can put together something like that. I only need to measure some angles, or just get a mirror, go there and try.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I guess that building a heliostat is a major project in itself.
You could try a static mirror arranged to sweep the bright spot across the foliage as the day progresses. A large mirror should provide the equivalent of maybe 1 hour extra sunlight per day. If this is significant then a band of different growth should be seen where the spot travelled each day.
Or just hang a sheet of Al cooking foil behind a test leaf/twig/branch for double sunlight ?
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Maybe a CR servomotor or one beefed up using a larger motor, gearbox (hint: swipe one from an old school stereo with the motorized tuners) and the original trimpot. For this application high speed is not required. Also relevant, use a simple magnet and 4 pin linear Hall sensor from a defunct VCR or floppy drive motor assembly
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.
Lens to make sun light on a same spot
