Reverse Engineering a circuit.

Hello,

I have a laser distance detector that I would like to reverse engineer. I would like to change out the laser device which is a class 2 to a class 1 so it will be not harmful to the eyes. Therefore I will need to reverse engineer the circuitry to understand more about the device and also to remove other functions that the device includes that I will not need. For instance I dont need a display I just need to be able to display different distances using some leds. Can someone help me in doing this work or help by pointing me where I can get some knowledge on doing this work? I will have more information when I get the device. What would you need to know to start the process. I figured most the device I would not use such as most the buttons or the display. Thanks in advance.

YOu will need to identify all the parts to drive the LED to ensure you do not over drive the replacement.
YOu will also need to do more homework and disclosure of necessary facts in this discovery, if you need help as I may be good but I am not a mind reader.

But if I stretch my mind reading ability.

I might suggest you get some laser mice and reverese engineer.

Notice how sensitive the reflection is to movement from 3m distance from the focal point. YOu will know when the mouse detects say a finger motion from this distance when the Mouse change from IDLE mode to ACTIVE mode.

If you only want to detect this action, all you need is a mouse. Then you can interface to the mouse for your desired output.

You may be amazed at the sensitivity to small motions at this distance. And that's my best advice. :roll:

Class 2 laser products are eye safe. Class 2 is a special case of Class 1 selected to cover visible lasers and relies on the blink reflex to prevent damage.

A class 2 laser rangefinder could work on a different principle to class 1 rangefinders, e.g. phase shift rather than pulsed. So, it is possible that what you want to do would simply require a complete re-design.

Keith

To reverse engineer a circuit, you need about the same level of knowledge as the original designer, possibly a better one, e.g. to identify unknown components. In the present case, this involves understanding the available operation principles of laser distance measurement.

As Keith revealed, your assumption about class 1 being eye-safe in contrast to class 2 is wrong. Perhaps you should start with unraveling this basic point.

Class1 = Safe
Class 2 = Safe if 1 mW max <0.25 Sec
Class 2A = Safe up to 1000 Sec due to spacial motion, such as grocery bar code scanners

https://en.wikipedia.org/wiki/Laser_safety

Use a Laser Mouse it is Class 1 and will detect objects > 2m away!
This is due to special design of refractive lens in the bottom of Mouse to split reflections with emissions and detect motion from interference patterns, so it very sensitive. I dont think you want to measure distance, just detect moving objects

The classification system has changed so Class 2A is now Class 2M.

Keith.

OK https://www.rli.com/resources/articles/classification.aspx in any case this distracting from my clairvoyant guess of why the user wants this laser changed in a distance measure instrument, when all they asked for in another thread was something to detect shoulders between 2~3m distance.
The spec is vague. Pls elaborate. But I think all he needs is the laser mouse.

SunnySkyguy said:

OK https://www.rli.com/resources/articles/classification.aspx

Click to expand...

That link is out of date. It says "The current version of the main ANSI Z136.1 Standard (Z136.1-2000)" yet the specification was revised in 2002. The USA accepted the revised system in 2007.

Keith.

hmm Copyright 1996-2012, by Rockwell Laser Industries, Inc. No it has the CLass 2M defn.

They can put whatever copyright date on the web page they like - it is still out of date. They list ANSI-Z136.1 (2000) as the latest - IT ISN'T. The latest version is ANSI Z136.1-2007.

https://webstore.ansi.org/RecordDetail.aspx?sku=ANSI+Z136.1-2007

Keith.

thanks for the correction

Let us not lose sight of Steph's need. Detect an object at lower power at shoulder height (I believe). 3~4m distance only,.
The mouse will do this but only with a focal line.

Steph. Please elaborate. or not...

OK Ultrasonic near field distance sensors work too.

**broken link removed**

Thanks for all the responses. I am familiar with the laser sensitivity. The application will be used to detect the shoulders of a person and be able to measure the distance from the device. I tried to find vendors that would be able to develop a device that would work for my needs and not be built into a box of some sort but just the board and the sensor and laser so I can be able to create my own encasement. Also this way would be the next best way in developing my device and will give me more knowledge into designing electrical circuits.

Please tell me if you need anymore information about the specifications of the device.

Is there a better way? I figured I could take the device and understand the powering of the device and how to collect the distance of the device and basically just add that. My product I want to design I want to be able to measure the distance from the product to a humans shoulders and be able to tell a person to move closer or farther using leds. So I was thinking of distance detecting increments of like 2-3 inches from each led.


Such as: Leds lined up like this: OOOOO and the center led is perfect and each one is 2 inches or so from the perfect spot.

Thanks,

I am not sure a laser rangefinder is the best approach for your application. They tend to either be short range, high accuracy or long range, low accuracy. For your short range you would end up with an accuracy far higher than you need. It would be an expensive solution.

I would look at ultrasonic methods, or triangulation of light. A camera based system is another option.

You implied you have already ordered something

I will have more information when I get the device

Click to expand...

- if so, what is it?

As FvM pointed out, reverse engineering a product is not easy - it would probably be easier to design your own. That would not be the case if you could take a product and use it "as is" and get the data you need from it.

Keith.

How about just put a small circle on the ground. WHen human stands in circle with crude sensor (dielectric reflection sensor), light goes on.

Perhaps it would be wise if you better define the environment of proximity sensing.
What are the possible sources of interference?
What is the acceptable detection of distance tolerance?
What considerations for height, reflections etc.

I will still consider using different devices but when I was considering them before I didn't think they would work too well in an outdoor environment and against the material that will be reflecting off of. The device I purchased was a measuring device form bosch called the DLR130. My intent of the device was to basically use the laser and the sensor and how they powered it and configure the output of the sensor my own way to make it work.

As far as Sunny's questions.

"What are the possible sources of interference?" - The device can be used both inside and outside and I don't see much of interference inside but outside there could be interferences with sun, material that it is relecting off of(Tshirt), for ultrasonic, echoing.

"What is the acceptable detection of distance tolerance?" - The distance will be no more than 3 meters and be no less that 2 meters. The distance delta needs to be about 1-2inches no more. I need to measure the distance from the shoulders because i have other devices that help where the person needs to be but will need to detect the shoulders to determine if the person is leaning over too much or not enough.

"What considerations for height, reflections etc." - I am not sure what you mean by height but for reflection it will have to be any type of Tshirt fabric and color.


Also now that I think about it I will be have two distance devices for this product (one for each shoulder) in order to detect some twisting movement. There will be interference between the two sources so maybe a good route to go would be to use a camera with two lasers for the device. But I would like to use a laser distance detector or something with more accuracy because a camera wont be able to detect that distance delta that well and maybe for add ons for future versions I might need a more accurate measurement.


I think that a product I develop myself will cost for a laser range finder will be around $40 just for the laser and sensor and a basic interface. An ultrasonic would cost about $30 for the same application as the laser. Am I close or not?

We dont get the whole picture of the environment this sensor will be working in.
For example I could suggest something totally impractical without your detail description.

e.g. an optical beam that must just touch the surface of the chest on both sides so that the T shirt interrupts the beam. The user can move until the side emitting light crosses the chest and the user can visibly see it.. Accuracy here can be < 1" and the user can control him self rather some other indicator display. The setup could be a beam from either side or one transverse beam where the user must interrupt the beam in the middle of their upper chest. A mirror in front of them could assist with alignment.

or even simpler a stretch string that the user must touch with each shoulder with the least possible deflection. (barely touching the string or clear fishing line) .


Is this for a passport photo shot:lol:?

If you don't supply more information, it is next to impossible to advise you well. By the way, as I mentioned in another thread, a rangefinder is highly unlikely to help you to measure to someone's shoulders, for the simple reason that most rangefinders will report an "error" if the target is moving even slightly! Rangefinder software would rather safely report an error than an incorrect reading. At least that is the case with Leica, and I don't see why the Bosch one would be any different. So if the target plans to keep his/her shoulders still, then maybe rangefinder will help, but unfortunately that's a very limited scenario.
You may have to re-think the approach.

Sorry I miss read the information you wanted for me. The device will be on the ground directly infront of the person with the persons body facing the device based on the led reading the person will tilt forward or backward. The device needs to adjust the leds as the person moves so that when he is in the right spot the center led will be the only one being lit meaning they are centered (no remote to recalculate the distance). So the device will be pointing up at the persons shoulders to measure the distance.

If I dont use a range finder will a ultrasonic be able to pick that up? Or a camera in the middle of daylight?

Thanks,

what is this for? My solution is much simpler. Why complicate things?

Im sorry I cant tell you what this is for but it needs to be a box that sits in front of the person performs a distance calibration on the shoulders. Like the bad drawing I have here.