- Visible and/or invisible laser hazard. Avoid eye and skin exposure to direct and reflected light.
NOTICE: This webpage and associated files is provided for reference only. This is not a kit site! It
is a collection of my work here at the
University of Toronto in the
Physics department. If you are considering using any schematics, designs, or anything else from here then be warned
that you had better know something of what you are about to do. No design is guaranteed in any way, including
workable schematic, board layout, HDL code, embedded software, user software, component selection, documentation, webpages,
All that said, if it says here it works then for me it worked. To make the project work may have involved undocumented
additions, changes, deletions, tweaks, tunings, alterations, modifications, adjustments, waving of a wand while wearing
a pointy black hat, appeals to electron deities and just plain doing whatever it takes to make the project work.
The Mini-Laser Driver is a generic driver for low power, uncooled lasers. Current is up to 200mA, corresponding
power up to about 20mW. A back facet in the laser assembly provides power feedback for a DMM to monitor.
Constant Current setting is provided by a pot on the unit. Optionally, a USB input may be added for computer
control, but current will never exceed the current setting from the pot. The unit is housed in a small box with
the one pot, a USB port, a power connection and the laser connections.
Schematics and PCB (done in Eagle but available as possibly outdated
PDFs), USB drivers and sample programs (list of all VB test files) and all of the
Delcom sample programs and information
(direct copy of the floppy) are available online. Can also view
project file list
How to Connect Laser
The lasers are ridiculously sensitive to everything and will self-destruct from the static charge created by the drop of
a hat. An unconnected laser is especially susceptible. As soon as possible, connect the laser to the mini-laser
driver for its protection. Be sure to connect it correctly or just order a new one. The black wire is the
cathode, the red is the anode (the diode 'arrow' points from red towards the black).
Ensure that the wires will not pull off, especially when the laser is running (proven in lab).
How to Install the USB Delcom Driver (windows 2000 or better, not meaning OS-X or Linux)
Delcom makes the USB interface ICs used. Connect the USB port on the mini-laser driver to the USB port on the computer,
the adaptor can be plugged in or not, makes no difference. The computer will say it cannot identify the USB device.
Click 'Okay' if given the choice, a USB wizard will appear. Use the defaults until it asks for a file then point
it to the
drivers. That is all.
How to Use the Mini-Laser Driver
The dial determines the laser current, where 0 to 10 [turns] on the dial means 0mA to 100mA. Before plugging in the
adaptor, turn the dial down to zero - unless it has been preset. When plugged in, there is a two second delay
before the laser turns on. As described, set the dial for the desired laser current. The dial lock can
be set to make sure it does not get bumped up. Be sure not to exceed the rated current!
If using the USB interface, the laser current can be set by the program, however, it will never be allowed to exceed
the dial current. The dial can be set to the maximum laser current and it will not be allowed to exceed it.