Seimans LGR7631A Laser Pointer





Introduction: Seimans LGR7631A Laser Pointer

About: Jack passed away May 20, 2018 after a long battle with cancer. His Instructables site will be kept active and questions will be answered by our son-in-law, Terry Pilling. Most of Jack's instructables are tu...

A while back a friend gave me this laser he found in a silicon valley surplus store. It sat around for a while before I decided to try to get it working. It is kind of beat up and looks like it had been sitting at the bottom of someone's junk box for a long time. The manufacturing date on the sticker on the tube says March 1987. After soldering a few broken connections I had it working with the pieces spread out on my desktop.

The driver board is mounted to the plywood with 4 #6x1 inch wood screws and 4 1/2 inch nylon spacers.

The transformer and the laser tube are each mounted with 2 #6x1/2 inch wood screws.

The laser tube is a Siemens LGR 7631A 1.5-2.5mW laser. (Not powerful enough to pop a balloon and not a lot more powerful than a little battery powered laser pointer.)

Do not point lasers at people, and I don't recommend them for cat toys, you might accidentally hit them in the eyes.

The laser can be found online, search for Siemens LGR 7631A.

Step 1: The Laser Tube

Shown lighted and unlighted.

Step 2: Connector

The wires from the driver board to the tube are very flexible fine stranded wire with thick insulation.

This is the polarized connector that connects the driver board to the laser tube.

Step 3: Transformer?

I am guessing a high voltage, high frequency transformer.

Connected with bayonet connectors, not polarized, I was careful to remember the polarity.

Step 4: Driver Board

The driver board and a closeup of the daughter board, which appears to be a filter and regulator.

Step 5: T-shirt

Just in case you are wondering, this is the image on the t-shirt that is partially covered in the intro picture.



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    11 Discussions

    Solution to this is ridiculously simple, just really obey the traffic laws by driving a few kph under the posted speed limit. This cuts down, eliminates, speeding fines and causes massive traffic traffic congestion. After all, if everyone is paying strict attention to the law who can complain so fines cease, traffic snarls, traffic camera company loses massive amounts of money as does the city and mayor gets in extremely hot water over massive traffic snarls, everybody suffers for a few days but cameras go away as probably does the mayor (on a rail covered with tar and feathers no doubt) people rejoice and problem is solved with no blood being shed.

    1 reply

    What a wonderful world this may be (Louis Armstrong)

    Luckily for the authorities, there will be left enough unlawful people willing to pay for it all. Sadly enough for the rest of us...

    Interesting, but unfortunately, what we (in Mexico City right-now) need, is a powerful one to blind the murderous Ticket-cameras that our extremely greedy present day government has allowed the vendor to install in our city. The fact is that those greedy and perverse companies that promote (Bribe would be a more appropriate term) the government officials to install and impose those cameras, to get a ridiculously effective business model: They get 50% of the money from the fines, and the city officials get the other 50%. All good and fine, except that the damn cameras are calibrated to shoot at EXACTLY the speed limit... absolutely NO margin is allowed. That could be acceptable IF the local Major had not LOWERED the speed limits WAY TOO MUCH, which is affecting our transit times. That is only a part of a nefarious politic that pseudo-ecological governants are imposing on us right now; their agenda is to "DES-INCENTIVATE THE USE OF THE CAR"...

    Now look at this closely: It is NOT done in order to LOWER the emissions, or "preserve" the environment. It is done because the pseudo-leftist government has declared all motorists to be "enemies of the environment". Included are conterproductive and improvised measures like the NARROWING of existing streets by installing Bicycle lanes (used by very few cyclists), Exclusive TOO-Wide bus lanes that remain EMPTY and UNUSED more than 99.5% of the time (while the fewer remaining car lanes remain now badly congested for miles, emmiting MORE gasses than before!), imposing too-slow speed limits that augment overall emmisions by making the use of lower gears necessary, thus raising emmisions and lowering fuel economy and also wearing down the engines sooner. And there in no proof that some of those cameras are working "properly": several of them have been observed to take a photo of the licence plate at semaphore ligths, BUT a careful analysis of the cars being photographed has shown that even traveling just slightly slower that the posted speed limit, the time while the semaphore displays a yellow light is too short,INSUFFICIENT to complete the crossing before the camera flashes, and a ticket is issued!

    As far as my poor understanding of the USA Constitution's Second Ammendement, was meant to defend the citizens of this exac type of government abuses... please comment on this. Of course, a LASER powerful enough neesd to be handled responsibly and carefully. Amclaussen, Mexico City.

    8 replies

    (Remember this is all hypothetical) You could use infrared LED's to drown out the license plate. They are as bright or brighter to cameras than normal LED's, but cannot be seen by human eyes. Just order a ton of bright IR LED's from China for a few dollars and wire them up. If one hypothetically wanted to destroy a camera, one might want to order a laser >2W (or 2000mw). That should do it; but the more watts the better. Hypothetically.

    As above: trying to cheat this way is simply illegal here. Once they catch you with such a blinding device (again, you will not be able to really blind the sensor, except you know exactly how to cheat) you have to pay. A lot. And you will probably loose your driving license for some time.

    I guess the laser won't help. As it's the laser's nature to not diverge it will hit only a little dot the size it's emitted from the front of the device where (well, almost) it later hits a surface. Since you don't know where the camera is mounted you will not be able to hit the sensor/film in the camera.

    Let's have a good and wild discussion on this... First, go and buy from eBay a powerful enough laser transmitter, park your bicycle to the side of the street and point your laser into the lens of the speed-trap. Wait some time and you will have the first victim of trap speeding by and camera operated. At the same time, your laser is pointed into the lens... after all, shouldn't there be be at least over-exposure?

    You could easily try this with your own camera. Place it on a tripod facing straight forward. From the bottom a bit in front use a laser pointer aiming directly in the lens. You may probably destroy the bits around the focus when switching to a high power laser. But the overall picture will definitely not be over-exposed. Maybe a bit under-exposed as the additional light might cause the overall picture to be dimmed down.

    Also, when they get you, you will be liable for the damage. Be warned - those cameras are very, very expensive. Not counting the penalty you will have to pay for using a dangerous device.

    You have to pay a penalty for using a high-powered laser? That's nonsense! If you REALLY want to pop one of those cameras, go for an SSY-1 Solid State Laser. If you get it focused in, I'd be surprised if that camera doesn't have a hole in the sensor.

    I don't know in which community you live. But here I'll get fined for damaging pubic property.

    And I forgot: those trap cameras are only in a near-infrared area. So you'd probably better off with a red light in this specific spectrum. Unfortunately it can be recognized. And when mounting it on your bike, then don't forget the big lead batteries you'll need to power it all them time. Or maybe you also mount a diesel generator on your bike xD