- Joined
- Jul 30, 2010
- Messages
- 215
- Points
- 0
Here is a build I just made using a PHR diode. There is a pot for controlling the current: 30-125mA. The unit is powered by a 9V AC adapter. A mini-tripod is used for mounting the laser.
Total Cost $47:
---------------
$10 PHR sled
$5 Moh heatsink
$2.5 Aixiz
$0.2 4x diodes
$0.7 LD1117
$0.5 LM7806
$0.06 10Ohm resistor
$4 25Ohm wirewound pot
$0.5 Knob
$4 On/Off switch
$10 AC/DC 9V adapter
$1 Female plug adapter
$8 Mini-tripod
I used 4 rectifier diodes in series to drop 3V before feeding the 7806 chip. This greatly reduced the amount of heat it has to dissipate. There is a little heatsink and thermal compound on the chip, with the current configuration it gets only barely warm to feel. The next chip is LD1117, but there is no heatsink on it because it stays completely cold.
The PHR is mounted in an Aixiz module with the stock acrylic lens. I put teflon tape on the threads to improve focusing. The Aixiz is JB-weld'ed on the inside of the case, however only the back of the module is - the front can be unscrewed in case the diode needs replacing. An aluminum heatsink from Mohrenberg did not fit very well, so using thermal compound and aluminum foil I wrapped the head of the module to fill the extra space and make a good conductive path for the heat.
Flaminpyro's wire is used throughout the build, with heatshrink tubing on all solder connections. I tried to make the wires as short as poissble, but still have room for play.
The "9V" supply actually puts out ~12V, so I had to bring it down to decrease the amount of heat. 4x diodes drop the first 3V, then 7806 regulates it down to 6V. LD1117 has a voltage drop of ~1V, the LD needs 3.9V@125mA. The result is just enough voltage in the end to drive the LD to 125mA. There is almost no heat produced by the driver circuit. The LD in its heatsink gets warm after an hour, but stays at the same temp from then on. I designed this for continuous operation, hence the AC adapter and minimal heat.
Current is limited to a maximum of 125mA by a 10Ohm resistor. A 25Ohm pot is used to control the power even further. It is a wirewound pot (thanx Vaporizer!), and has a nice 0-25 range. Accidentally soldering the legs on it wrong I now have to turn clockwise to decrease power and vice versa...
Total Cost $47:
---------------
$10 PHR sled
$5 Moh heatsink
$2.5 Aixiz
$0.2 4x diodes
$0.7 LD1117
$0.5 LM7806
$0.06 10Ohm resistor
$4 25Ohm wirewound pot
$0.5 Knob
$4 On/Off switch
$10 AC/DC 9V adapter
$1 Female plug adapter
$8 Mini-tripod
I used 4 rectifier diodes in series to drop 3V before feeding the 7806 chip. This greatly reduced the amount of heat it has to dissipate. There is a little heatsink and thermal compound on the chip, with the current configuration it gets only barely warm to feel. The next chip is LD1117, but there is no heatsink on it because it stays completely cold.
The PHR is mounted in an Aixiz module with the stock acrylic lens. I put teflon tape on the threads to improve focusing. The Aixiz is JB-weld'ed on the inside of the case, however only the back of the module is - the front can be unscrewed in case the diode needs replacing. An aluminum heatsink from Mohrenberg did not fit very well, so using thermal compound and aluminum foil I wrapped the head of the module to fill the extra space and make a good conductive path for the heat.
Flaminpyro's wire is used throughout the build, with heatshrink tubing on all solder connections. I tried to make the wires as short as poissble, but still have room for play.
The "9V" supply actually puts out ~12V, so I had to bring it down to decrease the amount of heat. 4x diodes drop the first 3V, then 7806 regulates it down to 6V. LD1117 has a voltage drop of ~1V, the LD needs 3.9V@125mA. The result is just enough voltage in the end to drive the LD to 125mA. There is almost no heat produced by the driver circuit. The LD in its heatsink gets warm after an hour, but stays at the same temp from then on. I designed this for continuous operation, hence the AC adapter and minimal heat.
Current is limited to a maximum of 125mA by a 10Ohm resistor. A 25Ohm pot is used to control the power even further. It is a wirewound pot (thanx Vaporizer!), and has a nice 0-25 range. Accidentally soldering the legs on it wrong I now have to turn clockwise to decrease power and vice versa...
Last edited:
