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Topic: Laser Control (Read 1 time) previous topic - next topic

vj01

Hi

i brought a wicked laser nano a green one

 http://www.wickedlasers.com/nano

from this url, and was looking to control it with my arduino.
the laser takes 2 x AAA batteries to power it, i am well aware of using a transistor to get my result and i have tried it and it works. the issue that i am having is that the transistor lowers the light of my laser and in turn isn't as powerful.

i am using a BC547B NPN transistor, so far the base is directly connected to the arduino without a resistor, the emitter pin is connected to the negative part of the battery and also the GND of the arduino and finally the collector is connected directly to the input of the ground for the laser.

as stated before it works but the light emitted from it goes very weak instead of how it naturally is

if it means changing the transistor can you recommend one

thank you

Dr_Ugi

If you are connecting toe transistor base directly to your output pin then you are shorting that pin to ground!

That will have two effects:

Firstly it will burn out your Arduino.

Secondly it will drop the working voltage of whatever power supply you are using because you are drawing so much current.  That will not at all help your laser power.

I would firstly try using a resistor (say 1K, no less than 220ohm).  That will protect your arduino and may help your problem.

If that is still not good enough, you could use a MOSFET instead of a bipolar transistor for very low "on" resistance.  I used a BS170 recently for Arduino control of a laser and it worked well (datasheet: https://www.fairchildsemi.com/datasheets/BS/BS170.pdf).

vj01

If you are connecting toe transistor base directly to your output pin then you are shorting that pin to ground!

That will have two effects:

Firstly it will burn out your Arduino.

Secondly it will drop the working voltage of whatever power supply you are using because you are drawing so much current.  That will not at all help your laser power.

I would firstly try using a resistor (say 1K, no less than 220ohm).  That will protect your arduino and may help your problem.

If that is still not good enough, you could use a MOSFET instead of a bipolar transistor for very low "on" resistance.  I used a BS170 recently for Arduino control of a laser and it worked well (datasheet: https://www.fairchildsemi.com/datasheets/BS/BS170.pdf).
Hi

thank you for the reply, you are correct i have a laser range finder attached to my circuit and as soon as i switch the laser on wirelessly the voltage drops and my laser range finder cant give me a accurate reading i will try to use the MOSFET transistor hopefully that works

ruchey

Wickedlasers is a good platform for buying the laser opinter.
Fiber Optical Transceivers Lover

Digitalis

There are a few solutions:

For one, an XOR gate with an inverted "B" input, the B input being the microcontroller;

What an XOR does is it turns on when inputs are inequal.
Here's the truth table below:

A0 B0 = OUT 0
A0 B1 = OUT 1
A1 B0 = OUT 1
A1 B1 = OUT 0

However, you might say, that would mean that the input from the board would always have to be on. You would be right; Hence why you'd need an inverter on B.

So then the logic would be something like:

A1 B1 = 0 (Input B is off but inverted, and A is still a working power source.)
A1 B0 = 1 (Input B is now on but inverted, meaning A and B are unequal.)

And any "A0" would just mean the batteries were dead and not be a problem.

I don't know if this solution would work as far as voltage/amperage on the XOR gate.


SOLUTION 2: Use the microcontroller to handle the current itself.
Either use the microcontroller as the way of powering the laser along with a logic level converter (You could even PWM control it!)

tl;dr
use an xor gate or a logic level converter and your arduino



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