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FrozenGate by Avery

(Wanted) detailed instructions Lavadrive + 803T

T

thejunkmonger

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Well my damn diode still hasn't arrived but I do have the lavadrive2. Can someone please post some detailed instructions on how to set the current on the lavadrive, I have some diodes IN4007 3 to be exact, is that what I should use? polarity of diodes? (which way should the stripe be pointing. Where I should measure the current? Between the battery and input? or on R10 that says I should measure the voltage??? if i'm measuring the voltage how do I know what current it is? please don't start quoting ohm's law because I do not understand math, even the simplest forms, have a short circuit in my brain. Thanks in advance.
 





Re: (Wanted) detailed instructions Lavadrive + 803

The easy way to get it running which I use, is hook up a cluster of led's and tune the pot all the way down. Make sure you dont leave the pot close to the setting that divides full current from minimum and remember what direction increases the power. Next disconnect the led's and short the the two wires that go to the diode, for added safety I solder the input + and - together. Be careful not to move the position of the pot, and proceed to hook up the LD. Now when you apply power your at the bottom of the output, slowly turn the pot up. Make sure you dont turn it in the wrong direction, as it will go from no power to absolute full! and p00f!
You will see about 3-4 phases where the brightness increases in steps, using a white sheet of paper helps show the brightness. Keep an eye on the LD modules heat, dont hold it in your hand (adds heat) and dont let it get warm.

Hope this helped ;)

Joe.
 
Re: (Wanted) detailed instructions Lavadrive + 803

thanks wannaburn but I was hoping of a way to directly set the current, say I wanted 90ma I'd hook up my dmm and set the pot where it reads 90ma. But I'd like to do this without the LD
 
Re: (Wanted) detailed instructions Lavadrive + 803

thejunkmonger said:
thanks wannaburn but I was hoping of a way to directly set the current, say I wanted 90ma I'd hook up my dmm and set the pot where it reads 90ma. But I'd like to do this without the LD
Click to expand...


I'm not "electronically inclined" so I rely on others to design and build the small stuff. I use Rkcstr's dummy load. There are instructions on how to build a dummy load somewhere in the forum. You hookup the dummy load, adjust the power, unhook the dummy load, short the circuit, attach the diode.

The dummy load and the diode will NOT be perfectly equal, but they will be close enough that the power will not be significantly different between dummy load and diode.

Peace,
dave
 
Re: (Wanted) detailed instructions Lavadrive + 803

daguin said:
[quote author=thejunkmonger link=1212599929/0#2 date=1212604610]thanks wannaburn but I was hoping of a way to directly set the current, say I wanted 90ma I'd hook up my dmm and set the pot where it reads 90ma. But I'd like to do this without the LD
Click to expand...


I'm not "electronically inclined" so I rely on others to design and build the small stuff.  I use Rkcstr's dummy load.  There are instructions on how to build a dummy load somewhere in the forum.  You hookup the dummy load, adjust the power, unhook the dummy load, short the circuit, attach the diode.

The dummy load and the diode will NOT be perfectly equal, but they will be close enough that the power will not be significantly different between dummy load and diode.

Peace,

dave[/quote

Thanks Dave, more stuff to buy arggggggg there must be something in all my junk that I can use to simulate the LD
 
Re: (Wanted) detailed instructions Lavadrive + 803

Just read your question again, must be the Tylenol #3's and the tooth ache :-[

Missed the point :-/
Anyway what i forgot to include, the diodes for polarity , the stirp indicates - should be connected to the + side. To measure the current, place your DMM in series with a 68ohm resistor for load. 68ohm is the load provided from Dr. Lava with his DIY kits, but im not certain if they are good outside the 6x builds. I would imagine they are close given the outputs.

OK now its back to spacing out... :o
 
Re: (Wanted) detailed instructions Lavadrive + 803

when i asked dr lava hisself, he said that a 60ohm resistor would be good as a dummy load, but he told me that i should measure the voltage, and work out the current using ohms law :

V =IR
 
Re: (Wanted) detailed instructions Lavadrive + 803

Ok, found it...

First of all, DON'T power it up without a load to measure the voltage! It's a current driver and it's gonna try doing the current through air, so it'll boost as high as it can, and could damage itself.

Second, don't measure the current only through your DMM. The LavaDrive can't work through a short.. It needs a load with a Vf of 2.4V or more. Otherwise, it'll dump all the current it can.


Use the diodes i sent you, wired in series with a LED, to increase the Vf (not the Low Battery LED ;)), THROUGH your DMM in the 2A range (with probes in proper sockets). Be careful about the polarity of the dummy load, or it'll be like an open circuit.

Then you can power it up and turn the pot and see the current. Set to 90mA, and that's it. Measure the voltage across the entire dummy load, while there are 90mA flowing through it. It has to be ABOVE 2.4V! Otherwise, the setting is incorrect.


Discharge the output caps by shorting the output BEFORE soldering a diode to it. Batteries should be as far away as possible at that point. ;)


Power it up with the diode, and it will run at 90mA.


If you set the current to 90mA with a dummy load, and verify the voltage is above 2.4V, the current will be the same with any other load, regardless of the Vf.



Good luck!



EDIT: Sorry, i was busy, and i just wanted to answer your question quickly.. Didn't read everything. You have rkcstr's dummy load. In that case, just wire it to the driver through your DMM, make sure the DMM is in current measuring mode, so it can let current through, and set the driver. Make the connections with alligator clips, so something doesn't get disconnected during testing. Later, you need to have everything soldered permanently.

I don't know the exact make up of Rkcstr's dummy load, but if you set the current to 90mA and verify the voltage as above 2.4 (or rather above 3V for safety), it's gonna do 90mA through any load. I think Rkcstr's can be set to around a reds Vf and a Blue Ray's Vf.. But it doesn't matter which one you use as long as the Vf is above 2.4V.

For added safety, you could then verify, that the current does indeed stay the same, when switching the dummy load's Vf. Here it really comes in handy, to have two DMMs.


Otherwise, most accidents happen, when people want to test something, to make sure it is safe, and they destroy it with the "testing".. :) I'm sure you won't do that. Most important part is, that you don't disconnect and reconnect the laser diode to the driver, and that you discharge the caps, before soldering it permanently.

If you should want to measure the current at a later point, buy a 1 Ohm 1% resistor and put it on the output in series with the load.. Then you can just measure the voltage drop across the resistor in mV, and the voltage ACROSS a 1 Ohm resistor in mV is the same as the current THROUGH a 1 Ohm resistor in mA. (U = R x I R = 1 => U = I => I = U)

You can leave the 1 Ohm resistor there all the time, as it does not influence the current or anything for that matter, and the power loss is negligible. But it allows you to measure the current any time, without unsoldering the diode, and risking getting it killed.
 
Re: (Wanted) detailed instructions Lavadrive + 803

wannaburn said:
Anyway what i forgot to include, the diodes for polarity , the stirp indicates - should be connected to the + side.
Click to expand...

If he wires the dummy load with the strip facing + of the driver output, the current won't be able to flow, and it'll act like an open circuit, potentially damaging the driver.

The strip has to face away from + on the output. If the diode was on the input, the strip would have to face +.
 
Re: (Wanted) detailed instructions Lavadrive + 803

Thanks for all the help guys, I still haven't had the courage to try any of the above with my $20.00 driver. I was thinking to do it this way let me know if it's a decent idea or not.

1) Wait for my LD to get here
2) Short output to make sure any caps are discharged.
3) turn down the pot to near min. (it's halfway now)
4) take off shorting bridge and attach blu-Ray Diode
5) Hookup DMM in series between battery and Lavadrive.
6) power up unit and slowly turn pot up until i'm at 90 to 95ma.
7) pray that I didn't ruin one or both.
8) Bask in the glory of the Violet Light (hopefully)

Let me know if you guys think this method will work, unfortunately all your explanations are great but if I don't have really detailed explanations and pics or drawings i'm afraid I might put something backwards and Poof no number 8.
 
Re: (Wanted) detailed instructions Lavadrive + 803

Yep, it's good if you measure the current on the battery side. This way you can have the diode soldered permanently and there is no chance of a momentary disconnection. And if your DMM should not be passing current, there simply won't be any power coming to the driver. If there was something wrong on the output side, you could blow the diode, driver or both.

Your plan looks very good. There is no reason it wouldn't work. Just double check all connections and the polarity, and you'll be fine. It's always scary, when you power these up for the first time, but you get used to it after a while.
 
Re: (Wanted) detailed instructions Lavadrive + 803

IgorT said:
Yep, it's good if you measure the current on the battery side. This way you can have the diode soldered permanently and there is no chance of a momentary disconnection. And if your DMM should not be passing current, there simply won't be any power coming to the driver. If there was something wrong on the output side, you could blow the diode, driver or both.

Your plan looks very good. There is no reason it wouldn't work. Just double check all connections and the polarity, and you'll be fine. It's always scary, when you power these up for the first time, but you get used to it after a while.
Click to expand...


Thanks Igor I think i'll stick to that plan then.
 
Re: (Wanted) detailed instructions Lavadrive + 803

ya know the easiest thing is to do thus.

1. turn it all the way down with led as load.
2. Solder in laser diode
3. power it up and read voltage across R10 (that's the green resistor) making sure NOT to short the resistor to the little square thing with a circle inside it (inductor) this will give you a representation of the current that it's currently set at, and you can tweak your pot - increasing until it represents 90ma or whatever your desired current.
 
Re: (Wanted) detailed instructions Lavadrive + 803

I realize this post is old, but why do you have to use a load with it to turn it down? Can you just turn down the pot( with no power hooked up) then hook up the LD and power supply, measure current across R10 and adjust as necessary? oR does the pot not have a stopper?
 
Re: (Wanted) detailed instructions Lavadrive + 803

good point but no the pot does not have a stopper. so it is very hard to adjust to the lowest point without a load.
 
Re: (Wanted) detailed instructions Lavadrive + 803

Thanks. better safe than sorry.... and 25$ in the hole
 
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