Here’s my prototype 455nm laser head, constructed from the front section of an Aixiz module threaded into a heatsink from an old ATX power supply. This sink has enough thermal mass for short 1W testing.
Connection
Connection to the laser diode at the back of the heatsink. Cable is heat shrink covered for strain relief, & hot glued to the sink for extra strain relief.
Beamshot 1
Looking down the beam, laser is under the camera. Operating around 1.2W here
Beamshot 2
Camera looking towards the laser. Again operating at ~1.2W output power.
The parts arrived for my adjustable laser diode driver! Components here are an LM317K with heatsink, 100Ω 10-turn precision potentiometer, 15-turn counting dial & a 7-pin matching plug & socket.
Driver Schematic
Here is the schematic for the driver circuit. I have used a 7-pin socket for provisions for active cooling of bigger laser diodes. R1 sets the maximum current to the laser diode, while R2 is the power adjustment. This is all fed from the main 12v Ni-Cd pack built into the PSU. The LM317 is set up as a constant current source in this circuit.
Installed
Here the power adjust dial & the laser head connector have been installed in the front panel. Power is switched to the driver with the toggle switch to the right of the connector.
Regulator
The LM317 installed on the rear panel of the PSU with it’s heatsink.
Connection
Connections to the regulator, the output is fully isolated from the heatsink & rear panel.
Here is a cheapo 500W rated ATX PSU that has totally borked itself, probably due to the unit NOT actually being capable of 500W. All 3 of the switching transistors were shorted, causing the ensuing carnage:
AC Input
Here is the AC input to the PCB. Note the vapourised element inside the input fuse on the left. There is no PFC/filtering built into this supply, being as cheap as it is links have been installed in place of the RFI chokes.
Input Side
Main filter capacitors & bridge rectifier diodes. PCB shows signs of excessive heating.
Filter Caps Removed
Filter capacitors have been removed from the PCB here, showing some cooked components. Resistor & diode next to the heatsink are the in the biasing network for the main switching transistors.
Heatsinks Removed
Heatsink has been removed, note the remaining pin from one of the switching transistors still attached to the PCB & not the transistor 🙂
Transformers
Output side of the PSU, with heatsink removed. Main transformer on the right, transformers centre & left are the 5vSB transformer & feedback transformer.
Output Side
Output side of the unit, filter capacitors, choke & rectifier diodes are visible here attached to their heatsink.
Comparator
Comparator IC that deals with regulation of the outputs & overvoltage protection.
Here is a Marmitek Gigavideo 30 2.4GHz wireless video transmitter, has a receiver paired which will be uploaded shortly. Here is a view of the antennae, the large flat one being the 2.4GHz directional, the whip antenna possibly performing IR relay functions for the remote control.
Bottom Label
For all those interested, here’s the bottom label.
PCB Top
The top cover removed reveals the main PCB. Big metal can is the RF transmitter circuitry. was encapsulated circuitry below that looks like an FM modulator for the whip antenna. Big TO220 package on heatsink is a LM7805 5-Volt regulator for the transmitter module.
These units work fantastically well when the antennas are aligned properly, at a decent range, however, they do have a nasty habit of doubling as a very effective WiFi LAN jammer.
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