Bored and good with electronics

[flare09]

Hey everyone. So im getting desperate. I need someone to help me design a circuit for me. Well...more design it for me. I need a driver bored for my laser project and its pretty demanding as far as the complexity goes. I have pretty much all the requirements I just can't figure out eagle or pad2pad. Not to mention I don't know the most efficient way to do it. I am offering to pay a little for the schematics, and if you have the equipment to, I will certainly pay for a completed board.

Any help is also appreciated if anyone wants to kinda walk me through eagle or pad2pad to do it myself. Or if anyone knows anyone. I just need this by early june...

Pm me if you're interested. Thanks everyone!

 

[AUS]

I use eagle, we have a purchased copy at work, but the free one will do 80x100mm boards. There are a heap of how to videos on the web showing you how to use it. The easiest way is drawing the schematic first and then it will generate a board layout from there. There are also a lot of resources and component libraries for eagle. Spark fun has some good tutorials on eagle.

Are you competent enough to design the circuit for yourself and test it on breadboard before making a board?

Are you going to build your own board or send it off to a manufacturer? I usually send the eagle files off to PCB cart in china and get them made there if I am doing a run of 10 or more boards.

There are lots of options depending on what you want to do.

 

[flare09]

Oh thank you, I mean it just seems like it would be better if someone did it. Mostly because im not sure how it works, and I don't trust myself with this. Its Driving three separate diodes and I don't want to burn all three out on power up. I could do the breadboard...but the final driver needs to be all smd. And there are alot of components...I think

 

[AUS]

When I do a proof of concept test on an SMD circuit I often solder wires to the SMD components and plug them into a bread board just to make sure everything works. You can also solder them onto a bit of perf board or something and join them with thin wires.

It looks like you already have a rough layout, If its a one off you can print a mirror image of it onto press and peel film with a laser printer and iron it onto a circuit board to etch. This sort of stuff Press N Peel PCB Film - Jaycar Electronics. I have done that in the past for one off designs successfully without needing to use anything other than a graphics program.

Lots of others stock it.

 

[flare09]

no i dont have any layout at all... i mean i know what i want it to do and all the current draws and such but i have no idea what components to use.

that stuff looks pretty cool, but i saw you can do the same with just a glossy magazine paper and a laser printer with a toner cartridge. a little bit cheaper... hahaha but i want this board custom made professionally, with a white silk screen and gold connectors. i will have to do my own board for the controller, its going to be rounded, but i just need the layouts done for me. and the parts list.

and yeah i could try a smd prototype but i burned out three transistors trying to tack wire on for a joule thief. so i will need to work on that.

 

[AUS]

Yes work on your soldering- there are kits you can buy to practice SMD soldering.

OK what are you building exactly? How complex is it? I have designed / laid out / built a few circuits in my time for work related stuff, but if its too complex I probably won't have the time. I'd start to look at data sheets & circuit ideas on the net and start from there probably.

 

[flare09]

well, i guess in overview, i am making a hand held so it all neds to be SMD, and fit into a 2 in. circular footprint, i need a driver for three laser diodes, with adjustable brightness, an output for a fan and pump, an LED array for the power level in the batteries, a charge circuit for two LiFe batteries and some status lights for that. a thermistor or something to warn me about temp overheat.

i was thinking i could lower the current then pulse the diodes to get the dimming down. but each needs its own controller.

i looked and digi has some ICs for charging the batteries, so i can use that, i had an idea for the temperature LED, and i found an led array for battery level, i just have to smd that and change voltage values, but im not sure how to do that. and i dont know the most efficient way to step down power for the fan and pump.

i feel like im missing something else but i cant remember exactly...

 

[AUS]

Wow.
That's an awful lot of circuit to squeeze into a handheld and sounds horribly technical for a first build without some experimentation and proof of concept circuits first!

You really need to test each bit first on its own and then test it together to we if it all works.

It also sounds like you may be hard pressed using all that electronics off batteries, unless you have a lot of them and they can handle the current. What voltage are you feeding this with and what capacity are the cells? What current draw and voltage are required for the fan, pump, and diodes (without worrying about the electronics)?

For diodes, what voltage drop for each, and what current range do you require?

I don't like building lithium battery chargers as there is too much that can go wrong, you pump too much current in and you end up with a bomb.

It sounds like a great project and challenge, but I'm not sure I would have the time to design, build and assemble all that. At least not enough time to get it done in less than a few months...

 

[flare09]

yeah, i have an inch on the y axis though so it can be two boards, the first board i would think will have the three drivers, i bought the diodes from DTR, im on break, cant grab the data sheets right now, but it was the 300 mW mit subi shi and i think the os ram 1 W 445. and i got a got a green off ebay with no driver, so it would go on the board, i have the specs for that at home.

as for the fan and pump, a simple resistor would essentially work. the fan is 5v and pump 6v each pull i think about 30 or 40 mW max. ill have to double check that.

im running this off two 3.2V LiFe batteries rated i think at 3200 mAh each and a max of 6A ouput CC, the LiFe are supposed to be more stable as far as charging and discharging abuse go.

i know all of this is possible, its just a matter of putting it together really...as far as the led array, i know that works im just not sure how to get that to smd, the original was done for a car converted electric diy. and the IC for the battery charging should be easy to hook up.
considering there are drivers that fit into the axis modules, three of those on a 2'' board should be no problem. and there was a post or two on dimming diodes with pwm. so i know that is possible.

i am in over my head though with my first build, you are right...

 

[AUS]

Things like Led arrays ant temperature sensors are easy that's the least of your worries, these are available off the shelf.

From experience, if you are building something this complex you usually go through a few hundred dollars in bits just testing and researching things and it takes you a month or two using all your free time...

 

[flare09]

Yeah. Im pretty committed though. And im really enjoying the learning so far. I wanted to take it with me to my family on vacation In june. But that's not happening I guess.

And this is what I enjoy doing in my free time. I build stuff. I have several other projects going right now. Its fun stuff.

Anyways thanks for all the info AUS