EEVblog #916 - Bench Lighting From A Dumpster LCD TV - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: August 26, 2016, 10:55:04 am
content: How to scrap a dumpster LCD TV to get work bench or architrave lighting.

author: WN1X
author_rank: Unknown
timestamp: August 26, 2016, 12:46:59 pm
content: Another nice teardown videoThe plastic "lens" functions as a conical mirror reflecting the upward directed LED "beam". Wikipedia describes it best:Total internal reflection is a phenomenon which occurs when a propagating wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary and the incident angle is greater than the critical angle, the wave cannot pass through and is entirely reflected.

author: urill
author_rank: Contributor
timestamp: August 26, 2016, 02:09:05 pm
content: If you stick the lens onto a phone camera, you can potentially use it as a 360 degree view lens

author: janoc
author_rank: Super Contributor
timestamp: August 26, 2016, 08:20:02 pm
content: Quote from: urill on August 26, 2016, 02:09:05 pmThat lens is probably way too crappy for that. However, I needed one of these to send IR signals to my Roomba - the charging base and the "Lighthouses/Virtual walls" use this type of lens to send the IR beacon signal parallel to the floor in 360deg angle around the device. The Roombas have another one like this but instead of the LED there is a phototransistor at the bottom, permitting it to capture the beacons from every direction.Roomba's sensor:And the "virtual wall/lighthouse" beacon:

author: abebarker
author_rank: Contributor
timestamp: August 27, 2016, 06:19:18 am
content: Thinking about peeling up the LED strips, using a solvent would probably make it easier and less likely to damage the circuit board.A good solvent for most adhesives I have run across is simple straight chain hydrocarbons. Zippo lighter fluid works well. It is a light to medium naphtha. Colman white gas is a light naphtha. That Goo Gone is a medium naphtha and light kerosene plus the fragrance (which you pay dearly for). Lamp kerosene would work I'm sure but will take a bit longer to dry. Longer still would be mineral spirits.The Ronsonol brand zippo lighter fluid is my personal favorite. It come in a conveniently sized bottle with a small spout that doesn't let out too much at one time. It seals well. It is cheap, usually under $3USD.

author: Kjelt
author_rank: Super Contributor
timestamp: August 27, 2016, 07:26:34 am
content: Nice teardownIMO the bench light is only half finished.You want to isolate the strips from touching and preferably putting those nice prism plastick sheets in front and make it more even lighting.I have ledpanels myself 3 rows of 11 leds on one pcb not as bright white but nice 3000K (led tvs need the video 6500K color temp) and need 36V each panel.There are many different lenses for all applications like focus for spots and creating beams from 10oup to hundreds.

author: EEVblog
author_rank: Unknown
timestamp: August 27, 2016, 08:51:17 am
content: Quote from: urill on August 26, 2016, 02:09:05 pmNope, I tried that.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 27, 2016, 09:14:48 am
content: Led lenses only need to distribute light in the right direction, so don't need to preserve any kind of geometry,so generally can't be used for any kind of imaging.Though it might be feasible to add a lot of post-processing to unscramble some sort of image.However some types do give some trippy effects if used with a small camera sensor where the LED should go.The narrow beam ones can be useful for making directional light sensors.

author: bryanrj1
author_rank: Contributor
timestamp: August 27, 2016, 10:23:00 am
content: Finally, after 18 months, me and John Bender have watched all 916 episodes. Can't think of anything better to do during Saturday detention.

author: Fungus
author_rank: Super Contributor
timestamp: August 27, 2016, 10:35:54 am
content: Quote from: bryanrj1 on August 27, 2016, 10:23:00 amHaven't you got one of those plugins that plays the video at 1.5x or 2x normal speed. They're a great help for videos which are mostly talking.

author: JWoodrell
author_rank: Contributor
timestamp: August 28, 2016, 11:17:36 pm
content: so an idea for the bench lighting why not use the engineering of those lenses to you advantage. keep the side emitter lenses in place but mount the diffuser / prism sheets in front of it like it was in the TV. just use scissors to cut them into strips appropriate to the new form. that is what I thought you were gonna do.just thinking out loud.

author: bitseeker
author_rank: Super Contributor
timestamp: August 30, 2016, 12:52:40 am
content: Quote from: Fungus on August 27, 2016, 10:35:54 amThe YouTube player has speed controls with 0.5x, 1.25x, 1.5x and 2x settings.

author: thunderbuny
author_rank: Contributor
timestamp: August 30, 2016, 01:37:24 am
content: HAI! (to do it the dave way)Can some one tell me how these lenses are called and were i can get them?i just moved in to a new house and these are perfect for the living room lighting i want to make.greets Dave

author: Kjelt
author_rank: Super Contributor
timestamp: August 30, 2016, 05:38:06 am
content: Search ebay for "led lens" and you find the focus clip on led lenses from 10 to 120 degrees, for 30 cents a piece, but those are not these ones.Still Dave could buy some to focus the light under his bench a bit.