Projector

Started by BeeJ in sci.electronics.basics8 years ago 3 replies

OT ? But you tech guys probably have some good suggestions. I don't need some biased sales person telling me anything. I want to set up a...

OT ? But you tech guys probably have some good suggestions. I don't need some biased sales person telling me anything. I want to set up a projector to view Blu-Ray DVDs. Room is of sufficient size. So I need one that: Very Bright High Resolution Very Reliable Costs less than $5K Other considertions? Is there one per above that is LED or laser driven rather than lamp....


Arduino choices

Started by Ivan Vegvary in sci.electronics.basics7 years ago 23 replies

Want to buy an Arduino. Too many choices that I don't understand. Prices = all seem to be nearly the same. Arduino will be used by a small...

Want to buy an Arduino. Too many choices that I don't understand. Prices = all seem to be nearly the same. Arduino will be used by a small group of high school students to build a "p= ick and place" robotics arm. School has a 3D printer and a laser cutter. = We also have lots of motors and servos from VEX robotics kits. We could us= e the VEX controllers but I would like the students t...


Where Is the Laser Sinking the Heat?

Started by Bret Cahill in sci.electronics.basics7 years ago 5 replies

If anything goes wrong with a non air breathing high energy density battery or any high energy density energy storage material it simply becomes...

If anything goes wrong with a non air breathing high energy density battery or any high energy density energy storage material it simply becomes an explosive and there hasn't been any clever way to get around this fact. A tiny flaw releases some energy and that area immediately heats up to 5,000 degrees vaporizing anything in its way until there's nothing left but a crater. If the entire ...


finding laser diode parameters

Started by Chris in sci.electronics.basics4 years ago 14 replies

I made a bulk purchase of red laser diodes off Ebay. There are three bags together unmarked. 25 of them are 3.3V., another 25 are 4.5V and the...

I made a bulk purchase of red laser diodes off Ebay. There are three bags together unmarked. 25 of them are 3.3V., another 25 are 4.5V and the other 25 are 5V. But like I say they're not labelled so I don't know what spec correpsonds with which batch. They're all in brass hosts with adjustable lenses. Is there a simple way to tell which is which - establish safe working current and volt...


driving a 1000 mW laser diode

Started by Ingmar Webb in sci.electronics.basics2 years ago 1 reply

I want to power a laser diode (the kind used for engraving) in a portable device for short periods with a 9V battery. The laser diode comes in a...

I want to power a laser diode (the kind used for engraving) in a portable device for short periods with a 9V battery. The laser diode comes in a tube with a focusing lens and trailing wires, and the spec says 5V 1A. This diagram seems to be the standard circuit for driving these. The LM317 spec says Vout is 1.25V above Va and it needs 3V of headroom. ---------- +9V----o-----...


Is Class 1 laser safe enough for baby eyes?

Started by Mr. Man-wai Chang in sci.electronics.basics2 years ago 11 replies

I meant, what if someone accidentally shine Class 1 laser into a baby's eyes? Would it hurt retina and leave a permanent damage? I know ......

I meant, what if someone accidentally shine Class 1 laser into a baby's eyes? Would it hurt retina and leave a permanent damage? I know ... I know... it should NOT happen. Adults are supposed to be very very careful. :) -- @~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!! / v \ Simplicity is Beauty! /( _ )\ May the Force and farces be with you! ^ ^ (x8...


Laser alarm

Started by AK in sci.electronics.basics11 months ago 8 replies

I was looking at this. "https://blog.prayogindia.in/make-laser-light-security-alarm/" Would this be an acceptable...

I was looking at this. "https://blog.prayogindia.in/make-laser-light-security-alarm/" Would this be an acceptable LDR? "https://www.jameco.com/z/CDS001-8001-Photocell-100mW-150Vpack-3Kohm-Max-Light-0-2Mohm-Min-Dark_ 202403.html"


Experimenting means there will be casualties :-)

Started by AK in sci.electronics.basics11 months ago 15 replies

This is part of a previous post. Thought I would start a new thread. "https://blog.prayogindia.in/make-laser-light-security-alarm/" The...

This is part of a previous post. Thought I would start a new thread. "https://blog.prayogindia.in/make-laser-light-security-alarm/" The directions are poor as hell as is his pictures. His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) When I hooked it up the first time using a 100 ohm resist...


Frustration

Started by AK in sci.electronics.basics11 months ago 63 replies

Electronic can be quite frustrating. I put together a circuit for a laser alarm. It does not work. There is no way to tell if a design...

Electronic can be quite frustrating. I put together a circuit for a laser alarm. It does not work. There is no way to tell if a design will be successful even if you follow the authors exact directions. I will keep plugging away and reading Practical Electronics for Inventors. :-)


Fresnel lens?

Started by AK in sci.electronics.basics10 months ago 7 replies

I am trying to maximize the amount of light that a red laser produces when it hits a cadmium photo cell. I went from a photocell with a small...

I am trying to maximize the amount of light that a red laser produces when it hits a cadmium photo cell. I went from a photocell with a small area to one with about double the area. I salvaged this from a laser printer and was wondering if that clear thing is a fresnel lens? [IMG]http://i64.tinypic.com/29w0bwi.jpg[/IMG] Am also trying to figure what that clear led is.? There is a ...