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Simple Way to Drive 3 volt Laser Module?

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JonSea

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I bought some cheap 3 volt laser line generator modules. My supplier was out of 5 volt units. I want to run them off a 5 volt USB power bank.

The laser module draws 20mA at 3 volts. It seems lile just adding an LED in series drops about 2.2 volts, and if the laser module is happy with sligbtly less than 3 volts, I'll have a pretty simple solution.


The reason for the laser line generator is interesting. When I was at pbysical therapy post knee replacement, I overheard my therapist talking to a gentlemen with Parkinsons Disease who was freezing in his gait. He'd take a step, then be unable to take the next step.

I had heard years ago that projecting a laser line to give people suffering like a target for the next step worked well. I asked my therapist of this technique was still used. Yes, he said, and they wanted to try it, but with the cost of laser being over $200, they hadn't tried it yet.

Crazy. i had just purchased a "good" line generator for 5 bucks. I quickly whipped something together for my next appointment. The feedback was my collection of parts really improved this guy's walking. Thst felt pretty good amd I made a second module to help another gentlrman.
 

JonSea

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Hmmm. I do have some DC-DC converter modules like Mike linked. It's almost) as cheap as an LED. Thanks for the reminder.
 

Reloadron

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The laser module draws 20mA at 3 volts.
With that in mind 5 volts - 3 volts = 2 volts / 20 mA = 100 Ohms. Just place a 100 Ohm current limiting resistor in series with your load (LASER). Wouldn't that work?

Ron
 
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