In my effort to find a solution to creating/modifying an LED light bar to function as a stroboscope, I was referred to this forum.
I am completely new to this whole realm and I am unsure whether this is an avenue I can venture down.
- My goal is to be able to have a strobe that I can adjust to match the rate of the objects I am monitoring (in this case the rate can very from 125'/min to 500'/min) and obtain a "virtual image" of what is passing by the light.
I am looking for guidance (a starting point really) on how to achieve the above:
The light I would be working with would be similar to this one.
Questions to start:
-which Arduino board to use?
-What other parts would be required?
-What "sketch" would work to achieve an adjustable strobe?
-How to put it all together?
Any Arduino board will do so get a Uno.
The web site is very lacking in important technical details like the current requirement and how the LEDs are powered. It could be that the internal electronics of this light do not allow it to be switched on and off fast enough for your needs. The question as to could it be dimmed was answered with a no. Dimming is done by turning the LEDs on and off rapidly which is exactly what you want to do, so it sounds like these LEDs are not right for you.
I agree with Mike. My recomendation for a first Arduino would be a Nano rather than an Uno because it can plug into a breadboard which makes prototyping so much easier. A downside of Nano for beginners is the need to install drivers for ch340 usb-serial adaptors on Windows & Mac (not required on linux).
Instead of that light bar, use a 12V led strip, or several in parallel if required. Use a p-channel mosfet with a logic-level gate to control them.
How will you adjust the strobe frequency? A pot would be the obvious answer, but you may find you need two pots for corse and fine adjustments.
Paul
I'll be contrary and say you can modify the lightbar but you need to be prepared for some pretty precise soldering and cutting of traces on the circuit board that the LEDs sit on.
If you do buy the light bar, remove the lens and reflectors and show us a good, clear picture of the circuit underneath. I'm sure we could show you what would need to be done to enable dimming.
Chagrin:
I'll be contrary and say you can modify the lightbar but you need to be prepared for some pretty precise soldering and cutting of traces on the circuit board that the LEDs sit on
I would have thought the complete removal of the driver board and replacement with a dim able constant current supply for each LED is about the best you could hope for.
What are you thinking you could do to a switching supply to make it dimmable?
Switching drivers for LEDs (DC input) for items like this are nearly guaranteed to be based off some chip that has a dimming input. I'm saying it's going to be a matter of isolating the appropriate input pin and connecting that to an output from an Arduino.
The 9th product picture of this example product shows the circuit board inside the unit. That's what I expect he'll find; a pretty textbook example of a PT4115 circuit.
It might be but I am not sure if it is within the scope of the OP to try the hack. Not all those sort of circuits are dimmable.
Thank you for your responses.
- I just received the light bar today.
I will open it up and let you know what I find.
It looks like I will try my luck with the Uno board.
I have attached some photos on the internals of the light bar.
- I'm hoping this will shed some light on the feasibility of attempting this project.
Can you read the markings on the 8-pin chip?
Spoiler alert: you're going to be desoldering one of the legs on that chip from the board and resoldering a wire to it.
negative. it may have been sanded off?
