High Current Toys for Big Boys

Lemme guess, a poorly thought out engraver?

LuxIgnis said:

Hello I bought a 4-6W 915nm and I want to also build my driver. Does your power supply have TTL???

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Please do yourself + everyone here a favour and do some research before you even begin to connect up that laser diode!

Cyparagon said:

Lemme guess, a poorly thought out engraver?

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Let me guess... a totally disrespectful person who jups to conclusions?

Do you know how to design an engraver better then me?

I built a working CNC machine that has a 0,05mm resolution, on my own, from my own design. Are you able to do the same?
I am not a mechanical or electrical engineer by the way, so I don't do this for work, but as a hobby, so I learn about lasers part time, and I am satisfied of the betterments and achievements so far. I do understand there's a lot more to learn, but your kind of answers are really disrespectful, provocative, and childish. Grow up!

Things said:

Please do yourself + everyone here a favour and do some research before you even begin to connect up that laser diode!

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Here is another person who thinks, without knowing or asking, and passes unwanted judgement.

I already have 4 types of goggles to protect my eyesight, just bough one that protects for this wavelenght.

I also bought all the necessary optics to focus to a pinpoint.

My question was about a driver schematic with ttl that is good for powerful diodes up to 8A, not just a power supply. Maybe my English isn't great, but I am sure your Italian is worse than mine.

Please people respect who you don't know.

Cyparagon said:

Lemme guess, a poorly thought out engraver?

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What do you think, for a poorly thought out engraver, it seems to be able to do a fine job even with a lowly 250mw red diode. It's a bit slow but it works fine, hence the need to experiment with bigger lasers. I have already tried the O-like 3,2W 808nm laser but it came without a FAC lens or a cylinder lens, so it focuses poorly. That one is sold, and will build my own 4 to 6 w, with a cylinder lens, and a good AR coated spheric, to focus to a pinpoint. The only thing so far that I still have to clarify is how to supply 8A and still have ttl I have a couple solutions already, using the BUZ11 mosfet, but it won't be constant voltage, I'd like to build one that has a constant voltage, like 3,3v or 5v max, so I can power it with 7v power supply and have a constant output. So far the regulators I saw have a max output of 3A, I can't seem to find a 5v regulator that can handle 8-10A. The not so elegant solution would be to run 3 or 4 of the smaller regulators in parallel and after the MOSFET to obtain that kind of output, but being just a beginner with electronics (as with lasers) I am sure there are better solutions to achieve the same result, hence the question.

I like to learn how things work. I have no problem buying a multi thousand $ engraver, but I am not planning on doing that as a job, since I am a Microsoft Certified Network Engineer, I make my money differently, not engraving some plaques. I just like to do it for friends, and family. The pleasure of a Do It Yourself is great, and asking inside a forum is supposed to be an acceptable thing to do.

Fun to see all the suggestions fail, you actually know pretty well what you are doing, nice engraver!
I'd recommend against the setup used here. First, get some BIG caps for filtering. And getting big resistor to dissipate the heat is crude. Designing a driver that can regulate the current with a single transistor or FET would be better. But this can be done (witt he caps, that is), it just a bit hard to adjust the current.

One time, in the past, i had to build a current regulator for one of those diode bars, for connect it to a low voltage, high current power supply (was a 3V 30A PSU) ..... i don't really remember all the part numbers, but the schematic was like this one (Sorry, i drawed it on the fly, i'm going home and have "family pack size" headache, so please don't take it as gold ..... just use it as track for experiments, if you want)



Just as idea .....

I think it's quite a nice design, I'm going to do it very similar.

thank you for the advice. I was thinking about using 3300 uf electrolitic caps.
For the resistors, I have some decent selection of 0,8 - 1 - 2 Ohm ceramic resistors in 10, 15 and 20w sizes to choose from. I'd like to use a mosfet for the faster switching capabilities, and also for low gate voltage. The parallel port seems to output 3 - 3.5v on the spindle-control output pin, and the BUZ11 seems perfect for it, with a max gate voltage of 4. It just remains to be seen how to regulate voltage, I'd like to be able to input anything from 6 to 12v, and not worry about changing output, it would simple to just use a 5v pc power supply and calculate resistor values on that voltage, don't know if it deserves to be called a driver.

One question. Are dimmers capable of withstanding that kind of power? I took a dimmer used in some speakers for volume control, do you think it can be used to regulate power? Would love to have like 10 power steps to be able to use on different materials.

What kind of dimmer are you referring to? Those to dim light bulbs? Speaker volume control is usually done with a pot and the amp after that. Larger pots are usually about 1/2 watt.