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Need help amplifying Pulse Train to drive Pen Laser tia sal2

Greetings All Need help amplifying Pulse Train to drive Pen Laser

I would like to create a pulse train using my sound card and cooledit pro (creating square waves) but I don't think I have enough power to drive my ULN2003A Darlington Transistor Array

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can anybody recommend a way to boost the voltage/current/power so I can drive my ULN2003A chip, I'm trying to make it very portable, is their a small chip that will allow me amplify my audio signal/pulse train?

For those of you who are interested this is what I intend to do.

1) Create various pulse trains by creating square waves in cool edit pro 2) Saving audio file as wav or mp3 onto my iRiver iFP 799T mp3 player 3) Using mp3 player with square wave audio pulse trains to drive my ULN2003A 4) Have ULN2003a and 3V battery power/pulse a small pen laser less than 5mW

I do have a bunch of 555/556 timers that could be made into voltage doublers

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but my mp3 player doesn't put out the required power to operate them.

If anyone has any other recommendations or another way I should go about it I'm all ears.

TIA

Reply to
not
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The output voltage is moer than enough; use a current limiting resistor from the output to the base of the darlington; 1K with 1V nominal output gives 1mA drive and that translates to way over an amp "saturated" (darlingtons *cannot* be saturated).

Reply to
Robert Baer

Perhaps you have already considered this in your plans, but all consumer audio devices that I have ever seen or heard of are AC coupled. So you will either need to keep the square wave frequencies high enough (at least in the low Hertz range) or you will need some sort of recovery circuit to convert switching spikes to flip-flop transitions. But sounds do-able, at least as WAV files.... I'd be really amazed if MP3s kept the waveform intact, though might be OK with the spike-to-flip-flop circuit.

You might want to take a look at my DaqGen freeware sound card signal generator for your initial experiments. It generates everything in real-time, not to a file, but has extensive options for creating all sorts of waveforms, including pulses of various duty cycles, PWM, etc. (There is an extensive Help system, but let me know if you need any additional help with this.) This might help you optimize waveforms since you can tweak things while everything is running on the test bench.

[SHAMELESS PLUG] DaqGen is the signal generator portion of the upcoming Daqarta system (couple more months), which *will* allow you to save waveforms to files. That's just a side benefit; it's main purpose is to create test signals and analyze the responses to those signals from a device or system under test. Lots of scope, signal averager, spectrum analyzer, and spectrogram options.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

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Home of DaqGen, the FREEWARE signal generator

Reply to
Bob Masta

Big Call!!! "darlingtons *cannot* be saturated" Stick 1mA in the base of first, small signal Amp Transistor could easily become 50-100mA into base of second Transistor of the Darlington Pair could be 2.5-10 Amps, which could easily saturate some Darlington Pair Amplifiers.

Daniel

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Reply to
Daniel

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