Voltage regulators require individual heatsinks!!!. Metal tab of LM7805 is connected to ground but in LM317 metal tab is connected to output terminal therefore common heatsink for both regulators is strictly unacceptable.
Heatsinks can be easily fabricated from available light gauge metal.
Couple custom shaped pieces of scrap aluminum will do the trick.
Use of thermal compound is preferable.
|Home-made heatsinks for spirograph controller.|
|Some times scrap aluminum can be very useful.|
|Thermal compound improves heat dissipation.|
Spirogarph requires DC power supply 9V 1A for 5V fans and 12V 1A for 12V fans.
ON - OFF switch and LED power indicator can be easily incorporated into base design.
As enclosure I prefer to use rectangular Hammond (7.6 x 4.4 x 2.2) plastic box. There's enough room to accommodate fans, controller and any of low power laser modules.
Fans and laser module are mounted on top cover.
Size of window opening depends on mirror's position and tilt and can be defined experimentally after mirror's final alignment. Dimensions may vary from 45mm x 45mm to 45mm x 60mm.
Rectangular piece of clear acrylic or similar transparent material should be glued into window opening to keep dust away from optical surfaces.
|Dremel always helps a lot.|
|Output window for laser beam.|
|All inner components of laser spirograph are installed.|
Final touch. Manufacturing and installation of faceplate and self adhesive rubber feet.
Faceplate is made by using heat toner transfer method. I use the same paper and the same technique that I use to manufacture PCB.
- prepare and clean piece of aluminum;
- iron artwork onto aluminum plate;
- soak it in water;
- remove paper. If you are not satisfied with result go to step 1 ;-)
- after plate's dried up transferred image becomes light gray in color because of paper particles that's embedded into porous layer of toner. I use permanent black marker to repaint image. Toner absorbs and holds marker's ink and becomes dark. Unwanted ink from aluminum surface can be cleaned by gentle swipe of cotton swab dampened with alcohol.
- apply protective layer of clear acrylic coating but do it with caution and go slowly. Coating solution contains chemicals that may dissolve and destroy image so first layer of coating should be very thin. Let it dry and repeat 5-6 times till you get even coating all over plate.
|Laser spirograph is completed.|
|Laser spirograph with optional power switch installed.|
|In every new build there's chance for design improvement.|
Now, let's relax and watch laser spirograph in action.