DIY Homemade laser diode driver

lapompo said:

Capasitor:
Cap. 0,47uF/50VDC MKT

Diode:
1N4001 diode 1A 50V DO41

LM317:
LM317AT Pos adjustable V-regulator TO220

pot:
Wirewound pot 100ohm 1W

resistor:
Res. 390ohm 5% 3W

Click to expand...

So are these the parts you've found from elfa and you'll want a confirmation if they are suitable? The resistor has too high a resistance, maximum current with that resistor probably will not be high enough to even make the LD lase. The capacitor is a 0,47uF, when it should be about 10uf, so you'll need more capacitance. I think elfa should have what you'll need. For example elfa's product number 64-671-12 is a 50ohm trimpot with a power rating of 0.5w, if you need more power, try 64-671-46.

Jaaju said:

[quote author=lapompo link=1185701612/1104#1104 date=1237071416]

Capasitor:
Cap. 0,47uF/50VDC MKT

Diode:
1N4001 diode 1A 50V DO41

LM317:
LM317AT Pos adjustable V-regulator TO220

pot:
Wirewound pot 100ohm 1W

resistor:
Res. 390ohm 5% 3W

Click to expand...

So are these the parts you've found from elfa and you'll want a confirmation if they are suitable? The resistor has too high a resistance, maximum current with that resistor probably will not be high enough to even make the LD lase. The capacitor is a 0,47uF, when it should be about 10uf, so you'll need more capacitance. I think elfa should have what you'll need. For example elfa's product number 64-671-12 is a 50ohm trimpot with a power rating of 0.5w, if you need more power, try 64-671-46.
[/quote]

Thanks for the answer =)

ye was as an comfirmation about the things I found would work So change the Capacitor I found first with 65-229-08 and one of the pots you showed and its spot on? =)

lapompo said:

Thanks for the answer =)

ye was as an comfirmation about the things I found would work So change the Capacitor I found first with 65-229-08 and one of the pots you showed and its spot on? =)

Click to expand...

Well, no. You'll have to decide on the current you'll want to use. This depends on the LD you'll be using and how much power or life you want from it. The resistor determines the maximum current you'll be getting, and the pot determines how much can you adjust the current. There is a xls-sheet for calculating the resistor/pot values, try searching ddlrescalculator_kendon_xls_001.zip

And about the capacitor, that must be the most expensive model they have, or something, over 7 euros!? Try 67-008-27 instead. In capacitors, you'll need enough capacitance (people have been using values from 10uF to abt. 47uf). At least one picture in this thread marks the capacitor as 10mF, which really is 10000uF, that'll be an overkill

So, to sum up:

Regulator LM317, there are some small variations, like LM317H, which can only handle 500mA, but if you do not have any special needs, take the LM317.

Diode 1N400X, so 1N4001 through 1N4005 will do, to my knowledge, the only difference between these is the voltage handling capability.

Capacitor, electrolytic versions will do and tantalum as well, these are the most used in this build, voltage rating preferably twice the voltage you'll be powering the circuit with and capacitance about 10uF-47uF.

Resistor and pot. 50ohm pot is good, 20ohm maybe even better, depending on the currents you'll want to use. The smaller the maximum resistance, the easier it is to adjust the current accurately. Power rating must be sufficient, 1,5W is enough for most applications, 0,5W may be enough for violet lasers. Same goes for the resistors. The values are up to you, use the chart or search the thread for calculating it for yourself. The total resistance, which is pot+resistor  range typically from about 3 ohms in high power applications to 30 ohms for lower power use.

And while you're at elfa, or ordering from them, get a  bunch of the 1N400X-diodes, they're cheap and can be used for making a test load to test your completed circuit on. And get a resistor with a resistance of 1ohm and power rating of at least 1W and you can build the test load. Search for DDL_circuit_test01_001.jpg, this shows the schematic with a test load for setting the current and checking the voltage.

And remember to short the output of the circuit for several seconds after you've tested it with the test load, without the batteries connected of course, before connecting the laser diode. Otherwise you'll kill the LD.

Thanks alot for the answer =)cleared out alot of frustration since as you said some of the pics showed 47mF so *shrug*

then I know where to start at quite abit better ^-^ the LD im gonna use is from a DVD Burner. as for test loads, adviasble to build the test load or use broken or working LD? got tones of them from dvd burners since I asked at work if people had some they where throwing away <.< ended up with around 21 dvd burners xP

I plan to make laser driver for PHR-803T diode.
This topic is pretty big, so reading 70 pages isn't easy job.

I need recommendations for laser driver.
First, which resistors should I chose to regulate diode up to highest safe limit?
What batteries are best for this driver and PHR-803T?
Is 100ohm potentiometer good choose for regulating current?
Max. power for this potentiometer is 0.2W, but that isn't problem for regulating LM317T, is it?


Also, I need to make laser driver for red laser diode that will give  200mW  or more power.
Again, I need recommendation for resistors and batteries.

EDIT1:
I'm going to use AAA batteries.
How many batteries do I need to power up PHR-803T through homemade laser diode driver?
Voltage of batteries are between 1.25-1.35V

I know it's boring  

EDIT2:
I have read the whole topic and have just more questions.
Many members are recommending 33ohm resistor to get 38mA.
Is it enough for PHR-803T?
Can I burn things with that current?

I need laser driver that will give maximum current (off course, maximum safe current... I don't want to burn my diode)
So, what current do I need for PHR-803T?

Another thing...I gave a lot of money for PHR-803T, so I need dummy load to test it before connecting BR diode.
Are 6 1N4001 diodes good as dummy load?

Where can I find the best laser host for BD diode and this laser driver?
So, I need 8-9V of voltage to power up this driver with BR diode.

btw...is this topic dead?

sorry just another stupid question this diode driver can be used for each laserdiode ?

At least one picture in this thread marks the capacitor as 10mF, which really is 10000uF, that'll be an overkill

Click to expand...

My drawing most likely, I have tried to change it where ever I can but so many people have copied it there are still some out there with the wrong notation....sorry.

sorry just another stupid question this diode driver can be used for each laserdiode ?

Click to expand...

Yes it can be used for all laser diodes up to 1A.
All you need to do is make sure the supply voltage is at least 3v over the that required by the LD. Rule of thumb, 7.2v for red 9v for blu ray.

Regards rog8811

I got perfect laser host for my new laser.
It uses 3x Ultra Fire 10440 3.6V batteries.
It means that voltage can go up to 12.6V.
And lowest voltage is about 9V.
I'm worried that PHR-803T can be overvolted with that input voltage.
I need other opinions.
Has anyone tried to connect PHR-803T on 12V with this driver?

All that will happen is the LM317 will convert any volts it cannot use into heat, the 803-T will not know the difference.

Regards rog8811

Thanks for answer

A did a test.
I need 12ohm resistor to get 110mA.

These circuits are cheap to make. If i where to buy a 101mA driver circuit, it will cost about $14 (USD.) I can build one of these at home for:

25-Ohm 3-Watt Rheostat - $3.99
Adjustable-Voltage Regulator LM317T - $2.29
4.7 µF Electrolytic Capacitor - $1.19
10 ohm 1/4W 5% Carbon Film Resistor pk/5 - $0.99
1N4001 Micro 1A Diodes - $0.99

Item Total: $9.45
Tax: $0.66

TOTAL: $10.11

You can go cheaper than that if you buy in bulk (and I don't mean 1000's)

LM317T
http://cgi.ebay.co.uk/10-pcs-LM317T...3286.c0.m14&_trkparms=66:2|65:2|39:1|240:1318
$0.48 each

1N4001
http://cgi.ebay.co.uk/100-X-1N4001-...3286.c0.m14&_trkparms=66:2|65:2|39:1|240:1318
$0.02 each

10uf 16v capacitor
http://cgi.ebay.co.uk/50-off-Electr...14&_trkparms=72:1683|66:2|65:12|39:1|240:1318
$0.05 each

10ohm resistors
http://cgi.ebay.co.uk/100-pcs-x-10-...14&_trkparms=72:1683|66:2|65:12|39:1|240:1318
$0.02 each

100ohm pot
http://cgi.ebay.co.uk/10-100-ohm-Tr...hash=item220297744692&_trksid=p3286.m63.l1177
$0.95 each


So that comes out to at just over $1.50 per driver. You may think you don't need that many.... when I bought my first 100 1N4001 diodes I thought I was set for life...I am on my second 100 now

Regards rog8811

Hey Guys
I'm new to the forum, but have been experimenting with this circuit for about 6 months now. I needed to run a phr 803t on 6 volts in a MXDL host . The LM317 has a voltage drop of 2.25 volts which makes it unsuitable for my application, so I set out to find a similar chip regulator that would work. I found the ST Microelectronics LD1117V which is a Low DROPOUT version of the LM317. It only drops out one volt instead of 2.25 volts. Mouser Electronics has these in the large TO220 case and the small DPAK and SOT223 cases. Last time I checked the price at Mouser was about 40 cents apiece. The circuit hooks up exactly the same way as the LM317. The LD1117V allowed me to run my phr on two CR123 lithium primarys. I hope this info will be usefull to anyone who needs it.
It worked for me. regards DIYer

Hi,

I gave this another go today and went to maplins to buy some stuff,

everything is correct exept the only 100ohm pot they have is round rather than like a block, and I have a spare multi turn 1k pot and was wandering because it'll be 10X easier to use the 1k pot, will it be completly impossible to set the driver to 200ma?

EDIT: Just solderd the 1K pot on as I couldn't figure out which pins are which on the round pot or have room to fit it in so I left it and put the 1K in... Guess I'll find out the answer to my question now :/ I only have a 4.7ohm resistor so I'll have to work out the current using ohms law

out comes the drawing It will be more difficult..so be careful.

Regards rog8811

Quick question. Lets say i stumbled upon a 2w 808nm diode that uses 2.4A. Would I be able to put two LM317's together in parallel with a 1ohm resistor to power it (with adequate heat sinking) or do I need to go another route?