81ma max output from rkstar micro-drive help

[ElektroFreak]

I have a blu-ray laser pointer made by a member here. The output of the laser seems real low compared to a PHR blu-ray I have running 160ma. I check the ma on the blu-ray made by the member and it is only 61ma. That explains the low output, LOL.

I unscrew the business end (an easy host to work on I might say) and attempt to adjust the output on the rkstar micro-drive with my Fluke meter in series with the negative pin off the diode. I can only get a range of 55ma-83ma. This is supposed to be a full range rkstar driver so something is wrong.

I am using two brand new lithium 3.0 volt CR123's in my host. That's 6.26 volts at the rkstar driver. That should be enough correct? or do I NEED two 3.6 volt CR123's to properly operate the rkstar micro-drive? I read somewhere that blu-rays with the micro-drive need 7.0-7.2 volts.

I checked rkcstr's webpage and the micro-drive full range should have a series resister (R1) marked 2R7. The rkstar driver I have has the series resister (R2) marked 4R7. I do not have a parallel resister on the R2 position of the driver board which I read is only for the pot range of adjustment, not max output.

I just want to interject that measuring current in series with the diode is a great way to kill the laser. When using linear drivers like the rkcstr and LM317, you can measure the current in series with the battery. That will protect the diode, and since the driver only draws whatever current the diode needs your result will be accurate. This only works for linear drivers, so no flexdrives. Those should be measured at their output using a test load.

And like everyone's been saying, your input voltage was too low. In my experience, a rkcstr driver powering a blu-ray requires ~9V of input. 7.2V if you're driving a red or IR diode.

 

[rkcstr]

You have a "6x range" driver. Should put out about 85 to 255mA across its range.

The theoretical minimum is 2.25V over your diode's voltage requirement... but, it may be more like 2.5V due to temperature, component variances, current, etc. So, you certainly should be using >7.5V to maintain a regulated current to a blu-ray diode. 9V-12V will give you some headroom as the batteries drop in voltage as they are expended, not to mention if your diode draws an above average voltage.

 

[sportcoupe]

Just out of curiosity, who sold you this laser (just to protect other potential buyers from encountering the same troubles) ?

Jake21 sold me the laser.



.

 

[jake21]

it was fine where i had it set at 150ma and ran well on 2 reachable batteries till he took it apart and is running it at 200ma that requires more voltage....if u don't like the host send it back and ill place it in a 3aaa host so u can use 3 10440 batteries

 

[sportcoupe]

Jake sent me a host, no batteries, an aixiz module with a SF-AW210 blu ray diode and a rkcstr driver in a heatsink installed on the Cree host. There was no lens on the aixiz module at all. I paid $120 for this? I asked myself....

I bought two Cr123 lithium batteries, stole a lens from my PHR MXDL build and tried out my "new" laser. It sucked! I pulled the tail cap and read the ma with my Fluke meter. I got 61ma reading. No wonder this BR sucked.

I asked Jake21 and he said my batteries sucked and I needed 3.6 volt CR123's to get the 200ma setting I requested. I checked his theory by connecting the laser driver to my bench power supply set to 8 volts and was able to get up to 200ma then. I don't believe now that a blu-ray should be driven with anything under 7.5 volts so even two 3.6 v cr123's won't give full output unless they are fully charged.

Rkcstr himself says his micro-drive needs 9-12 volts when used with blu-ray. Should I return the laser and ask for a refund from jake?

 

[jake21]

how can u ask for a refund when its not broke and u took it apart ???

ill pay for the return shipping and switch the host.....

 

[sportcoupe]

jake sent it to me with no batteries and no lens. I put batts in it and it was very weak. I unscrewed the tail cap and measured ma draw. I unscrewed the front end and turned the pot full left and full right, I measured 51ma to a max of 82ma.

How did I take it apart and break it? It is a bad design and this is the second time around with Jake21. He should have never put that driver in that host.

I will let the forum decide what I should do. Is this worth the $120 I paid jake? Should I let him "fix" it a 3rd time or ask for a refund? Members, please give your opinion.

 

[chipdouglas]

i'm passive aggressive. don't listen to me! I would let him make good on it, but silently blow up on the inside. let this be a lesson to every body. always check the product instantly. we deal with hobbyists making things for hobbyists. we are not dealing with new product. so take pics instantly if possible. I know it sounds like a nuisance but it will save some headache.

michael

 

[jake21]

we agreed on me getting a host that takes 3aaa and making a heatsink for it and ship it off to him and he will do the rest.......would any one have a nice 3aaa host in mind i can buy/use

 

[pseudolobster]

jayrob's sidebutton host comes with a holder for 3x AAA, $35 with heatsink.

In any case, jake21, you shouldn't be selling BR builds that only take 2 lithium cells.. You really do need at least 3x 3v to drive a BR with a rkcstr driver.

I'm glad that you're willing to fix this though. Sportcoupe, I'd suggest you take Jake up on his offer to make things right.