Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

DDL driver HELP needed

P

paulham

0
Joined
Feb 16, 2008
Messages
22
Points
0
hi i was wondering if anyone could help me out!

i have built the ddl driver to the exact spec of the schematic, but when connected to a LED, with the pot (1turn 100ohm) set at the highest resistance, it doesnt turn the LED off, is this normal?

also what readings should i be looking for from my driver?

i have a 16x diode (bought from stonetek), but havent it connected yet, ive only used an LED AND also the dummy load (consisting of 4 diodes and the 1ohm resistor).

but i dont know what multimeter readings i need to achieve to run my LD without killing it, but to be able to burn!

i have read loads of the forum and used the search feature, but i havent been able to find a definate answer.

your help would be greatly appreciated
thanks
 





P

paulham

0
Joined
Feb 16, 2008
Messages
22
Points
0
well to be honesty, i havent recieved the diode yet, i live in england so its taking its time to be shipped over here.

could you please explain to me what the mA, Mw and all that stuff means. in technical terms, also in basic terms, (eg, 180mA will/not burn)?

i am new to this, but can make circuits and use a multimeter. im just getting to grips with all this laser info and jargon!
 
P

paulham

0
Joined
Feb 16, 2008
Messages
22
Points
0
ok so i should tune my POT untill i get 180mA (on the mV setting)

i was testing all that earlier!
im just going to do the tests again and i will take readings, i will post them on here.
if you will be kind enough to check them out for me, just to make sure im on the right track :)
 
C

chido

0
Joined
Dec 4, 2007
Messages
1,918
Points
0
Of course I'll check them I don't want you killing the diode when it gets there. ;D
Also if you can, take some pics when you're testing the driver, just to make sure everything is fine, and if you can't, that's fine too. ;D
 
P

paulham

0
Joined
Feb 16, 2008
Messages
22
Points
0
my pot is 100ohm and is not even a full turn, this is the link to the component i bought (wont let me post a propper link though)
CODE: UF97F

maplin.co.uk/Module.aspx?TabID=1&ModuleNo=6499&doy=16m2



These are my readings, do they look ok?-

Pot Highest resistance(fully counter clockwise)-
mV - 12.5 mV
V -  2.801 v

Pot half resistance (half way)-
mV - 21.3 mV
V -  2.827 v

Pot lowest resistance (fully clockwise)-
mV - 251.5 mV
V -  3.125 v

the closest i could get to 180mV was-
mV - 179.0 mV
V -  3.093 v

i am using 5 AA alkaline batterys at the moment, i wil be getting 6 Ni-MH Rechargeables soon.
 
C

chido

0
Joined
Dec 4, 2007
Messages
1,918
Points
0
Yup, they look ok, now when you get your diode, you're going to have to take the same measurements, but instead of using the 4 silicon diodes, you'll be using the LD itself. First you solder two wires to the laser diode, then you solder the negative wire coming from the laser diode to the negative wire coming from the driver, then you place the 1 ohm resistor between the positive wire coming from the laser diode and the positive wire coming from your driver. Then you take your multimeter, set it to mV and place the probes like you just did, the positive between the resistor and driver, and the negative between the resistor and the laser diode.
Finally, you turn your potentiometer to full resistance, turn the power on and then slowly turn up the pot while looking at your multimeter until you reach 180mA. Once you do that, you solder the positive wire from the LD  to the posistive wire from the dirver, and you're done.
Oh and here's a pic taken by Skram0 that shows the polarity of the laser diode:
 

Attachments

  • Laser_Diode_Pinout.jpg
    Laser_Diode_Pinout.jpg
    31.4 KB · Views: 4,176
P

paulham

0
Joined
Feb 16, 2008
Messages
22
Points
0
ok so i use the 1ohm resistor just so i can get the 180mA. then i take the resistor out, ok! understood!
i will make sure to short the cap before hand. just incase any voltage is in there at all!

i have taken i photo of my driver on my phone (sorry about the bad quality).
the circuit could of been smaller but i attached my switch wires on to the board aswell, easier for me. here it is... hopefully!
 

Attachments

  • SP_A0321.jpg
    SP_A0321.jpg
    232 KB · Views: 455
C

chido

0
Joined
Dec 4, 2007
Messages
1,918
Points
0
Hey, that's good for your first driver. :) Also you don't have to take out the resistor, you can leave it in there just in case you want to change the current or if you accidentaly turn the pot and you need to readjust it, that way you won't have to cut or desolder the wire to measure the current again.

PS: I can tell you've been reading, you knew you had to short out the capacitor before putting the LD in, and also to use 6 nimh batteries instead of putting in 6v only. Most people just start asking questions and don't read a lot. Good for you, you're special. ;D ;D ;D
 
P

paulham

0
Joined
Feb 16, 2008
Messages
22
Points
0
lol thank you!
and yeah that is a good idea about leaving the 1ohm resistor, so anytime i want to re-adjust i can connect it again!

i read up alot, i always read people asking silly questions in forums, and i see the responses people give most of the time... "use the search" or "this has been covered so many times"
i didnt want to add more on to a forum.

so now i have to wait for my diode! thats the long part i supose!
i ordered on 07th feb, so nearly 10 days. and the website states "Marked as delivered for internal tracking purposes." so hopefully its left the country by now!

should i wait untill i get my 6 nimh, or will it be ok to test the diode using my 5 alkaline AA's i have already?

i will get clearer photos soon enough, and i will also get a photograph of the finished project with laser shots and videos (if all goes to plan) :p
 
C

chido

0
Joined
Dec 4, 2007
Messages
1,918
Points
0
Alkalines sag a lot, but you can still use them while you wait for the bad ass nimh.
I'll be waiting for all those pics and vids. :)
 
Gazoo

Gazoo

0
Joined
Jun 9, 2007
Messages
3,206
Points
38
paulham, good job...I never am as neat as most of the people around here.. ;D

chido...way to go helping out, you are doing a fantastic job and you may feel free to use my "canned response" anytime you feel the need..lol
 
C

chido

0
Joined
Dec 4, 2007
Messages
1,918
Points
0
Hey look, a compliment from the boss. ;D Thank you.
All right I get to use the canned response, that's good, I think I'm going to need it a lot. ;D
Guess I'm following in your footsteps. :eek:
 
Gazoo

Gazoo

0
Joined
Jun 9, 2007
Messages
3,206
Points
38
10 posts so you should be able to post the link now.. ;)

You should be getting around 110mw's with 180ma's.
 
You must log in or register to reply here.




Top