DIY Laser Torch

jay, if I have the negative just touching that metal screw-in-piece, is it routed all the way to the negative terminal?

Abray said:

jay, if I have the negative just touching that metal screw-in-piece, is it routed all the way to the negative terminal?

Click to expand...

Yes, the MXDL body IS the negative side of the batteries, when the swich is on...
Jay

I'm pretty sure everything that could possibly go wrong has. I was working with the circuit today and found that the negative lead wasn't my problem at all. The circuit just doesn't work for some reason. I unsoldered it and re soldered it and nothing. I checked the resistor, and tried to check the capacitor, but my multimeter couldn't do it for some reason. Is there any way to check the LM 317? anyway, I hooked an actual LED up and it worked for a little bit, and then all of a sudden when I put the batteries back on, the LED ceased to work. and that was the first time I got the circuit to work in a LONG time. I have switched out LM317's and everything. it just hates me for some reason.

I seriously don't know what to do now. I am going to order new parts YET AGAIN, and if it doesn't work this time, it is no longer worth my time as it will obviously not work for me. I almost want to send the circuit to somebody here and have them tell me if it works for them. see if they can get it to work. I know I sound as if I have all the problems and such, but I promise you I'm not stupid and I seriously can't find the cause for this lol.

I can try to put some pictures up, but I don't know how much that will help.

also, is it possible that I have old solder covering the wires, preventing current from getting through? or does old solder work just like new solder? and if that is my problem, how do you clean wires of solder?

Abray said:

I'm pretty sure everything that could possibly go wrong has. I was working with the circuit today and found that the negative lead wasn't my problem at all. The circuit just doesn't work for some reason. I unsoldered it and re soldered it and nothing. I checked the resistor, and tried to check the capacitor, but my multimeter couldn't do it for some reason. Is there any way to check the LM 317? anyway, I hooked an actual LED up and it worked for a little bit, and then all of a sudden when I put the batteries back on, the LED ceased to work. and that was the first time I got the circuit to work in a LONG time. I have switched out LM317's and everything. it just hates me for some reason.

I seriously don't know what to do now. I am going to order new parts YET AGAIN, and if it doesn't work this time, it is no longer worth my time as it will obviously not work for me. I almost want to send the circuit to somebody here and have them tell me if it works for them. see if they can get it to work. I know I sound as if I have all the problems and such, but I promise you I'm not stupid and I seriously can't find the cause for this lol.

I can try to put some pictures up, but I don't know how much that will help.

also, is it possible that I have old solder covering the wires, preventing current from getting through? or does old solder work just like new solder? and if that is my problem, how do you clean wires of solder?

Click to expand...

One practice that I have found very helpful, especially when building the driver as small as you can, like making it fit onto the MXDL round circuit board with the silicon diode and cap on there as well...is the use of the DMM. Checking for continuity after you solder each component in place. Also checking that the parts that aren't supposed to touch other parts are not connected. (using the DMM) Especially, checking the little round circuit board. Check from where the battery connects, to the LM317 leg. You must make sure that all of the connections in the circuit are correct, and not connecting any other component or ground that they are not supposed to. Only when you are sure you have it right, then put the driver in place, and test for continuity between the MXDL body, and the negative lead that you have soldered onto the driver circuit. Then, put the batteries in and check for voltage first, then current.

Probably, it is best to solder the silicon diode and cap, direct to the LD. Like DDL showed in his first page of this thread. That way, it protects you from 'forgetting to discharge the cap after testing the circuit'. Also, it leaves more room on the MXDL board. The only thing, is that with my heatsink, there is limited room inside. (under the heatsink) There is enough, you just have to be careful when you position the heatsink, making sure that the components aren't going to 'smash' into each other...
Jay

i got the driver built last night and everything installed... just waiting on the batteries :'( . i did check everything that i could check without voltage and everything seems to be ok so far. i even went as far as testing it real quick with just a 3.0 volt battery to see if i even saw anything red come from the diode and it shined red... then i stopped. i just couldn't resist seeing if it even worked or not. tonight will be the true test if my batteries come and after they get charged/tested. pics to follow soon

Holy crap- Nice job!!

how exactly do you check for continuity? my DMM explains it like this (and I don't get it): "Touch the test leads across the circuit you want to measure. 'shrt' appears and the buzzer sounds if the circuit resistance is less than about 50 ohms (meaning the circuit is continuous or shorted). 'open' appears and the meter's buzzer does not sound if the circuit resistance is greater than about 50 ohms (meaning the circuit is not continuous)."

can somebody explain that? or tell me a better way to check it.

and I don't think the problem is any unwanted connections. I have the circuit out and spread out, meaning I can see everything perfectly, and no wires are even close to touching

SUCCESS! got my batteries in and charged and it was such a pain waiting too lol. i had my meredith unit together wrong (don't ask) but after i got it together correctly and a bit more filed off of it it focuses just perfectly and i have been lighting shit on fire all night hehe. i will get some pics soon but i am having too much fun popping balloons and messin with my neighbors dog ;D

Abray said:

how exactly do you check for continuity? my DMM explains it like this (and I don't get it): "Touch the test leads across the circuit you want to measure. 'shrt' appears and the buzzer sounds if the circuit resistance is less than about 50 ohms (meaning the circuit is continuous or shorted). 'open' appears and the meter's buzzer does not sound if the circuit resistance is greater than about 50 ohms (meaning the circuit is not continuous)."

can somebody explain that? or tell me a better way to check it.

and I don't think the problem is any unwanted connections. I have the circuit out and spread out, meaning I can see everything perfectly, and no wires are even close to touching

Click to expand...

Abray, that's all I meant by checking the continuity. Just to check if things are connected. And that things which are not supposed to be connected, are not. One of the main things to test for, is the pinched ground. Test this after you mount the threaded ring with the driver 'pinched' in place, then touch one probe to the MXDL body, and the other probe to your negative lead coming off of the driver. You should hear the beep. (closed) This test will tell you that you have it grounded properly...
Jay

will the two resistors and lm317 do as a driver, or it it likely to go tits up?
(I have a heatsink)

robjdixon said:

will the two resistors and lm317 do as a driver, or it it likely to go tits up?
(I have a heatsink)

Click to expand...

What LD are you going to run with the driver? I am guessing, since you have one of my heatsinks, that you are going to use the MXDL. If, you are going to harvest an open can diode. Then, just the LM317, with a 3 ohm resistor is your driver. You will also need a silicon diode and a cap. DDL has parts listed for the silicon diode and cap here:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1185701612
The 3 ohm resistor will give you 420mA's. Or, you could go with a 3.3 ohm resistor instead. This would give you somewhere around 380mA's. These suggestions are for an open can diode...
Jay

ok i have had this working for about a day or so now and my batteries died so i had to recharge them. they only lasted about a total of maybe 1 hour "on" time... does this seem short to anyone? maybe they are shit batteries but i recharged them and it is back to normal. voltage after charging is 3.8ish or so volts... sometime readings as high as 4.1 depending on how i hold the probe.

no, seems normal i think , 1 hour "on" time is a long time

jayrob said:

[quote author=robjdixon link=1186966870/285#297 date=1205096834]will the two resistors and lm317 do as a driver, or it it likely to go tits up?
(I have a heatsink)

Click to expand...

What LD are you going to run with the driver? I am guessing, since you have one of my heatsinks, that you are going to use the MXDL. If, you are going to harvest an open can diode. Then, just the LM317, with a 3 ohm resistor is your driver. You will also need a silicon diode and a cap. DDL has parts listed for the silicon diode and cap here:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1185701612
The 3 ohm resistor will give you 420mA's. Or, you could go with a 3.3 ohm resistor instead. This would give you somewhere around 380mA's. These suggestions are for an open can diode...
Jay
[/quote]

I will be using a pioneer 115d open can diode. why can't i just use the resistors and lm317 mentioned in te guide?

robjdixon said:

I will be using a pioneer 115d open can diode. why can't i just use the resistors and lm317 mentioned in te guide?

Click to expand...

I believe the guide shows 2 - 10 ohm resistors in parallel, if I remember correctly. This is the same as a 5 ohm resistor, giving you 250mA. With an open can diode, your only going to get around 150mW's power at that current. In fact, at that current, you will get more power out of a Senkat diode. If you want your open can to be at it's best, use at least a 3.3 ohm resistor at the LM317. This would give you around 380mA's. I like the 3 ohm best - 420mA's. Here's a graph that drlava showed on the open can's. This is for a Pioneer 112D, but it is the same for the 115D...
Jay

so i don't need a silicon diode and cap?