DIY: LPC-815 at 0.45A, Ehgemus Easy Build Host, Flexdrive v5

Hello,

I'd like to share my recently completed project. My apologies in advance for the quality of the pictures. I do not have the camera except for the one in my Samsung Vibrant

Materials:
Diode: LPC-815 (This GB)
Driver: Flexdrive v5 (set it myself to 0.45A)
Host: Easy Build (made by Ehgemus)
Connecting Wires: Silicone Wire (From Flaminpyro)
Module: Aixiz module with acrylic lense

Below are the essentials used for the construction.


Zoomed-in shot on the diode.


Parts of the host.
This is the contact spring for the positive terminal.


The insert to hold the cr123a battery with the hole for contact spring.


The top part with the heatsink




Diode is about to be pressed into the Aixiz module:




Since I do not have a custom diode press, the diode was not pushed in any further than this


Flexdrive v5 with wires soldered on.


Using the jump wire method to set the range on the driver for current adjustment


The prototype board is used to create the dummy load circuit with 4 1N4001 diodes to simulate Laser diode's voltage drop and 1ohm 5W resistor to measure the current output from the driver.


The current is set to 0.45A (must be somewhere between 445mA to 454mA I guess). Unfortunately, I completely ignored the fact that 2000m means 2000millivolts and should have used that setting to set the current precisely! Thank you pHeneX for pointing this out for me!


Diode is soldered to the driver. Sanity check


Could not get rid of the solder blob on the negative contact....


Used the electrical tape to isolate the driver and put a knot on the wire leading to the positive terminal to prevent from adding unnecessary tress to the driver.


Module is in. Wire connected (had to resolder a more flexible wire to the spring, the one it came with would not bend easily and looked to be 20Ga or close).


Some teflon tape on the lens mount to prevent it from shifting around in the module.


Completed pointer


The beam shots!! But first I need to make the smoke mix
These instructions are provided for education purposes only!
Components Potassium Nitrate (almost 99% in stump removers sold in Lowe's and Home Depot), Sugar, Iron Oxide (Fe2O3) to increase the rate of reaction.
Ground sugar and potassium nitrate separately. Mixed KNO3, Sugar and Fe2O3 in approximately 3:2:1 proportions respectively. Mix carefully. Excess friction may ignite the mix.
I mixed KNO3 with Fe2O3 first (for some reason...).


Transfered the small amount onto the metallic cap and placed it into a copper dish.


Igniting the mix. Get a mask, breathing the fumes is not good for you!




Here we go!








Lights on!







Note: One problem I encountered was a bunch of glue in the switch of the host. When ON, it would make a high pitched noise and the beam was less brighter. I guess it worked as a resistor of a sort. Took it apart, removed glue. I have compared the beam from the pointer to the module with the LPC-815, and driver at 0.45A connected directly to the cr123a battery. After the glue was removed, beams were the same intensity.

Note 2: After a day of use the switch started to go bad again and I could notice the beam flickering plus the noise. The contacts in the switch are bad. So I had to take the whole tail-cap apart again, including the switch.
Applied some solder on all the contacts. There was a cylinder at the top of the tail-cap that made contact with the battery's negative terminal, and since I destroyed the plastic holding it in place I had to solder some spring instead to the leads going from the switch.

It looks FUGLY but seems to work great now.


Final thoughts: This host is perfect if you are a beginner and looking for something inexpensive, sturdy and with decent size heat-sink It is easy to assemble and you can get an insight and tips on how to build your own host from scratch in the future!

Enjoy!

I like it... I like the knot in the wire... good thinking. I have a simular build at home got the host from Home Depot. It's using the same driver at close to the same settings.

I used my "swappable" module in that unit. It is one of my favorite reds. If I can remember I'll post a pick of it in a PM for you.

For now you can kinda see it in this pick
its the red one 6 from the left

ehg did a nice job on the heatsink and you look like you take a good approach to your builds. :gj:

jander6442 said:

I like it... I like the knot in the wire... good thinking. I have a simular build at home got the host from Home Depot. It's using the same driver at close to the same settings.

I used my "swappable" module in that unit. It is one of my favorite reds. If I can remember I'll post a pick of it in a PM for you.

For now you can kinda see it in this pick
its the red one 6 from the left

ehg did a nice job on the heatsink and you look like you take a good approach to your builds. :gj:

Click to expand...

Thank you for your comment I really appreciate it and it is very encouraging!
To be completely honest the knot was not my idea. As I was completing the build I decided to add it because I remembered reading about it here somewhere.
Quite a collection of lasers you have! Very impressive!

A bit offtopic: Today, late night before posting the thread I showed the pics to a friend who is an electrical engineer at Upenn and he sent me a link to his current project

YouTube - Quadrotor test 09/12/2010

My first though: Man that would look awesome with lasers! Gonna try to convince him to put one or two on

P.S. Looking at your picture again I realize that I need to get myself some lens protecting caps.

Nice job, love the pictures

Nice build and good walk-thru! :beer:

The protecting caps we use are tailcaps from switches, they can be found here:
DealExtreme: Search for tailcaps (199 products in 20 categories) :yh:

Kevlar said:

Nice build and good walk-thru! :beer:

The protecting caps we use are tailcaps from switches, they can be found here:
DealExtreme: Search for tailcaps (199 products in 20 categories) :yh:

Click to expand...

Thank you for the reply and for the info!

Nice build Try using "2000m" on your multimeter, that way it will display how much millivolt you're getting. Range is 0mV-2000mV.

pHeneX said:

Nice build Try using "2000m" on your multimeter, that way it will display how much millivolt you're getting. Range is 0mV-2000mV.

Click to expand...

LOL I'm an idiot or it was so late at night when I assembled it that I never thought that "m" stands for "milli". I'll check it today on my microboost that was purchased preset to 450ma

P.S. It is confirmed I am an idiot http://laserpointerforums.com/f51/how-set-flex-drives-current-45653.html in the video he clearly says "2000 millivolts" Oh well, even though it is obvious I totally ignored the fact Thank you for correcting me. I learned something new!

Nice build and very well presented! :gj:

A laser danger label would look nice on the heat sink with the power rating.

Vaporizer said:

Nice build and very well presented! :gj:

A laser danger label would look nice on the heat sink with the power rating.

Click to expand...

Thank you Kind Sir. I was actually thinking about it just now. I have a sticker printer at work I'll just have to wait until everyone leaves

don't worry about pressing the diode any further. pressing them to the point where they were recessed was just required with the phr because it would not allow proper focusing if it weren't. With red diodes it doesn't matter.

gillza said:

LOL I'm an idiot or it was so late at night when I assembled it that I never thought that "m" stands for "milli". I'll check it today on my microboost that was purchased preset to 450ma

P.S. It is confirmed I am an idiot http://laserpointerforums.com/f51/how-set-flex-drives-current-45653.html in the video he clearly says "2000 millivolts" Oh well, even though it is obvious I totally ignored the fact Thank you for correcting me. I learned something new!

Click to expand...

I would reconsider using that microboost on a 650nm build. It would do Ok
on cheap 3AAA configuration, but any batt. that would have some juice
would fry that diode. Boost only.

Anybody care to chime in on that topic for clarification.:beer:

jander6442 said:

I would reconsider using that microboost on a 650nm build. It would do Ok
on cheap 3AAA configuration, but any batt. that would have some juice
would fry that diode. Boost only.

Anybody care to chime in on that topic for clarification.:beer:

Click to expand...

I originally planned on using the Microboost for this build but then found flexdrives sold on "laser surplus parts dot com" and got one from there.

This build uses Flexdrive v5. I had a spare microboost drive that I had ordered from dr.lava preset to 450mA. So after I was pointed out that I could have used 2000m setting to get more accurate reading (shtupid me) I thought that I will go home, hook the microboost to the dummy and get the readings to confirm (which I did eventually ).

But you are asking a question that I would like to get answered as well especially in the light that FlexDrives v5 are out of stock pretty much everywhere they were sold before. I thought that microboost will boost the voltage only if "diode needs it" like with Blu-ray diodes. Here is what Morgan posted some time ago on Flexdrive thread

http://laserpointerforums.com/f64/l...lavadrive2-fits-pens-22502-55.html#post774710

Anybody can shed some light here? Can Microboost be used for low power diodes?

Also this may sound stupid, but is there a way to determine the current output from the driver ones it is conected to the diode? (wihout desoldering it and putting on dummy load). I can read a voltage drop across the diode but without the Resistance value can it be determined?

Yes you can do this, but becouse of the lack of room between the diode and driver once hooked up it presents a danger with the probes touching a part and shorting out of the diode. I have done this last night with success and I read 524mA also at 3.75 forward voltage (which is high 2.2 for the LOC).
using Microboost and 3 AAA batt. I dummie tested the driver to see where I set for max and it was at the 780mA range. So when I dummie tested at 524mA with the crap batteries the current was in a constant state of drainage... unable to take a steady setting I canceled the experiment.

Later that evening I figured I'd take it all the way, well I used a 3.7v CR12 batt full charged and ended up frying that diode... LED heaven for that one.

jander6442 said:

Yes you can do this, but becouse of the lack of room between the diode and driver once hooked up it presents a danger with the probes touching a part and shorting out of the diode. I have done this last night with success and I read 524mA also at 3.75 forward voltage (which is high 2.2 for the LOC).
using Microboost and 3 AAA batt. I dummie tested the driver to see where I set for max and it was at the 780mA range. So when I dummie tested at 524mA with the crap batteries the current was in a constant state of drainage... unable to take a steady setting I canceled the experiment.

Later that evening I figured I'd take it all the way, well I used a 3.7v CR12 batt full charged and ended up frying that diode... LED heaven for that one.

Click to expand...

To make sure I understand correctly (sorry not much sleep today thus I'm very slow): you have set the Multimeter to DCA and read the current directly on your driver that is set to 524mA and hooked to red diode? The driver in question is Microboost?

BTW at 450mA I was reading 3.08V across the diode with flexdrive.

Well I have a digital meter... the setting says millAmps. I believe your says DCA for Direct Current AMPS if thats what your asking yes. I on purpose left the LOC pins hanging off a little more than I usually do.

I have those probes that have the little hooks hanging off of them and attached the black to the + anode of the diode and the red probe on the laser casing to take the current set. Remeber that I had some very declining AAA and it was hard to get any solid #'s