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NOTE - I started this project earlier this week before SMIDSY's post.. just so you don't think I'm ripping him off..
Pumped up red keychain pointer
Brief: Modded a ~$5.00, 5mW red keychain pointer. Replaced diode with 15-20 mW 635nm (sdl7501) + apc power supply (ns102) + Meredith acrylic lens.
Here a picture of it (middle) compared to LED flashlight (left) and lighter (right):
If you live in the US, these pointers can be found at Target, in the pet section. Not bad for a $5.00 pointer! (or, here: http://www.thepuppyshop.com/laserchase.html) During my first violet pointer build I ripped apart one of my 'homemade' 635nm flashlight laser pointers (more, here: http://www.candlepowerforums.com/vb/showthread.php?t=140955) to get at the Meredith housing and optics. In the process I shattered the diode window on my beloved 635nm diode. This diode has lasted for years.
After picking the shards of glass out of the window, I was happy to see the diode still lased. I decided to attempt to resurrect this diode, this time in a truly pocketable package.
Below you can see can exploded view of the 'laser chase' pointer. After working on this thing I must say it's something of a masterpiece of simplicity and economy. All brass construction. The switch assembly includes a resistor + an 'open can' diode chip directly mounted to the PCB. If you're using well behaved batteries, like alkaline or silver oxide, a resistor is really all the power supply you need. It also sports a focusable lens. Pointer runs off three 'LR44' button cells. I recommend the Energizer 357 high drain equivalent. Beneath the pointer switch you can see what I'm replacing it with - the 9mm SDL diode, socket and the tiny ns102 APC supply.
Here's a closeup of the pointer switch + PCB, beneath it you can see its replacement the 9mm sdl7501, and the weee little ns102 power supply, just a few mm's per side. I have nothing but good things to say about the ns102 - it's an APC supply, meaning it uses the third PD pin on the diode to keep the optical output constant, adjusting the current as needed. It works with an input voltage range of 2.5-9 volts, and also has a slow start. This diode+power supply has lasted me many years, 100's of hours of use and has taken a lot of punishment. It works well in all temperature extremes, I've tested it from 0 (F) to over 90 (F).
I started the mod by separating the PCB from the brass housing. I then sawed off a bit of the back of the brass housing and glued the 9mm diode can to it. The 9mm diode can has a large metal lip, and its diameter was just a little less than the brass pointer assembly, so I was able to get it centered well. Next I cut down the PCB and ripped the resistor off it. I then glued the ns102 to the end of the PCB, and soldered the diode legs directly to it.
As luck would have it this assembly fit back into the pointer casing, and it worked!!! However tragedy struck just a few hours after completion. The pointer abruptly stopped working. The autopsy revealed why: repeatedly pushing the button had ripped the diode legs off the ns102 supply, as well as pulling the traces off the PCB. AAAAUUUGH!!! I spent a couple days sulking. I had flunked the mechanical part of the design, and needed a new approach. The switch had to be braced better.
I came up with a new plan. I decoupled the switch&power supply from the diode. I then did reconstructive surgergy on the ns102. I nearly went blind and berserk soldering wires to something about the size of a housefly's butt. Sometimes I had to solder the wires to the traces leading to where the solder pads had been on the PCB. Eventually I was successful. The idea was to glue the switch into place first, and then solder the wires to the diode and push that into place.
In the pics below you can see the pointer switch, with the NS102 glued to the end of it. Both sides of the ns102 are used - the side with the smd ic is glued, the other side has the trim pot and a few smd parts. Q-tips were employed as structural elements, and the switch was glued and braced into place about the botton, with the wires sticking out the front of the pointer. A royal PITA. Next the the diode assembly was soldered, and then pushed into place.
Pics before this happened
This was not fun. I had chosen too heavy a guage of wire, and during the press fit of the diode assembly into the pointer I was worried I'd rip the soldered wires off the NS102, or the diode. Since the ns102 was glued into place I would have been f*cked if this happened. Of the four wires, three are four the diode, the fourth is the '+' connection, squeezed between the case and the brass flange.
Anyway, it worked!! The switch is now well braced and functional.
Next, lens choice. In the image below you can see the three lenses at my disposal - from left to right, Meredith glass (shimmed with electrical tape), Meredith acrylic, and the plastic lens that came with the pointer. The Meredith acrylic worked, and that's what's in there!
The head of the pointer is a little cockeyed. The + wire squeezed between the pointer case and housing was too fat. I decided to leave it this way, rather than risk ripping any wires out by pusing it all the way in.
So, I'm happy with it. This pointer is about as bright as a 50-60 mW DVD diode (~655nm) would be. Fairly gory! My 125mW red burning laser appears no more than twice as bright.
I'm using 357 batteries.. the current draw of the diode is 80-90mA, so I doubt I'll get more than 1/2 hour of continuous use.. more than enough for the little pointer however. My old boss will sell me these batteries for $1.00/each, a better price than the $2-3 each at the drug store.
Below is an honest beam shot in a smokeless room with the shades drawn.
And the pointer.
Pumped up red keychain pointer
Brief: Modded a ~$5.00, 5mW red keychain pointer. Replaced diode with 15-20 mW 635nm (sdl7501) + apc power supply (ns102) + Meredith acrylic lens.
Here a picture of it (middle) compared to LED flashlight (left) and lighter (right):
If you live in the US, these pointers can be found at Target, in the pet section. Not bad for a $5.00 pointer! (or, here: http://www.thepuppyshop.com/laserchase.html) During my first violet pointer build I ripped apart one of my 'homemade' 635nm flashlight laser pointers (more, here: http://www.candlepowerforums.com/vb/showthread.php?t=140955) to get at the Meredith housing and optics. In the process I shattered the diode window on my beloved 635nm diode. This diode has lasted for years.
After picking the shards of glass out of the window, I was happy to see the diode still lased. I decided to attempt to resurrect this diode, this time in a truly pocketable package.
Below you can see can exploded view of the 'laser chase' pointer. After working on this thing I must say it's something of a masterpiece of simplicity and economy. All brass construction. The switch assembly includes a resistor + an 'open can' diode chip directly mounted to the PCB. If you're using well behaved batteries, like alkaline or silver oxide, a resistor is really all the power supply you need. It also sports a focusable lens. Pointer runs off three 'LR44' button cells. I recommend the Energizer 357 high drain equivalent. Beneath the pointer switch you can see what I'm replacing it with - the 9mm SDL diode, socket and the tiny ns102 APC supply.
Here's a closeup of the pointer switch + PCB, beneath it you can see its replacement the 9mm sdl7501, and the weee little ns102 power supply, just a few mm's per side. I have nothing but good things to say about the ns102 - it's an APC supply, meaning it uses the third PD pin on the diode to keep the optical output constant, adjusting the current as needed. It works with an input voltage range of 2.5-9 volts, and also has a slow start. This diode+power supply has lasted me many years, 100's of hours of use and has taken a lot of punishment. It works well in all temperature extremes, I've tested it from 0 (F) to over 90 (F).
I started the mod by separating the PCB from the brass housing. I then sawed off a bit of the back of the brass housing and glued the 9mm diode can to it. The 9mm diode can has a large metal lip, and its diameter was just a little less than the brass pointer assembly, so I was able to get it centered well. Next I cut down the PCB and ripped the resistor off it. I then glued the ns102 to the end of the PCB, and soldered the diode legs directly to it.
As luck would have it this assembly fit back into the pointer casing, and it worked!!! However tragedy struck just a few hours after completion. The pointer abruptly stopped working. The autopsy revealed why: repeatedly pushing the button had ripped the diode legs off the ns102 supply, as well as pulling the traces off the PCB. AAAAUUUGH!!! I spent a couple days sulking. I had flunked the mechanical part of the design, and needed a new approach. The switch had to be braced better.
I came up with a new plan. I decoupled the switch&power supply from the diode. I then did reconstructive surgergy on the ns102. I nearly went blind and berserk soldering wires to something about the size of a housefly's butt. Sometimes I had to solder the wires to the traces leading to where the solder pads had been on the PCB. Eventually I was successful. The idea was to glue the switch into place first, and then solder the wires to the diode and push that into place.
In the pics below you can see the pointer switch, with the NS102 glued to the end of it. Both sides of the ns102 are used - the side with the smd ic is glued, the other side has the trim pot and a few smd parts. Q-tips were employed as structural elements, and the switch was glued and braced into place about the botton, with the wires sticking out the front of the pointer. A royal PITA. Next the the diode assembly was soldered, and then pushed into place.
Pics before this happened
This was not fun. I had chosen too heavy a guage of wire, and during the press fit of the diode assembly into the pointer I was worried I'd rip the soldered wires off the NS102, or the diode. Since the ns102 was glued into place I would have been f*cked if this happened. Of the four wires, three are four the diode, the fourth is the '+' connection, squeezed between the case and the brass flange.
Anyway, it worked!! The switch is now well braced and functional.
Next, lens choice. In the image below you can see the three lenses at my disposal - from left to right, Meredith glass (shimmed with electrical tape), Meredith acrylic, and the plastic lens that came with the pointer. The Meredith acrylic worked, and that's what's in there!
The head of the pointer is a little cockeyed. The + wire squeezed between the pointer case and housing was too fat. I decided to leave it this way, rather than risk ripping any wires out by pusing it all the way in.
So, I'm happy with it. This pointer is about as bright as a 50-60 mW DVD diode (~655nm) would be. Fairly gory! My 125mW red burning laser appears no more than twice as bright.
I'm using 357 batteries.. the current draw of the diode is 80-90mA, so I doubt I'll get more than 1/2 hour of continuous use.. more than enough for the little pointer however. My old boss will sell me these batteries for $1.00/each, a better price than the $2-3 each at the drug store.
Below is an honest beam shot in a smokeless room with the shades drawn.
And the pointer.
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