Laser Cutter Build Night: Electronics Attached, Hardware Ready to Go

Tonight was a very productive night!  After the encouraging cutting results of last night, I attached the Raspberry Pi, EasyDriver, and laser driver boards to the laser cutter plywood base.  I used screws and nylon tubing standoffs for the Raspberry Pi and hot glue for the laser driver.  However, since I blindly followed this guide for assembling the EasyDriver pin headers, I had pin headers on the top and bottom of these boards.  This made attachment complicated, because I had wires below the circuit board.  To get around this problem, I raised the EasyDrivers off of the base by sliding their mounting holes over sharpened chopsticks and securing them with hot glue.  I did the same thing for the computer fan that cools these electronics.  I decided not to use an enclosure because of the hassle of managing all the wires inside such a small space and also because of the difficulty of preventing large stresses on the connections.

Looks pretty sweet!  I like how the fan is aligned diagonally to the other boards.  Additionally, I noticed that the LM317 on the laser driver was painfully hot during its tests with the dummy load (this simulates the laser; read the previous post for details), so I used the failed laser diode heatsink to cool it.  I also used a bit of zinc oxide baby cream to stand in for thermal compound.  I believe I read somewhere that this is a good substitute because zinc oxide is the main ingredient in commercial thermal pastes.

As you can see in the pictures, I am using a ribbon cable to attach the control system electronics to the Raspberry Pi.  This will enable me to semi-easily remove and replace the Raspberry Pi if I need it for other projects.  A cheaper controller would have been nicer because then I could just leave it on the laser cutter forever.  However, since I spent upwards of $50 on the Pi and all its extra peripherals and power accessories (and since I only have one), I don't really want to leave it there forever.

I also epoxied the power switch to the edge of the base so it is nicely accessible and stable.

After I completed all these tasks, I looked into the X axis stalling issue.  After a cursory debugging run-through, I found the problem.  The base of the moving platform was running into the Y axix stepper motor when the X axis got to a certain position.  Stupid me.  *Sigh*

Finally, I coded a test function to ascertain the engraving/cutting capabilities of my laser cutter on different materials.  I called it "drawMrSmiley()".  Using this, I can set a cutting speed and an engraving speed and see if it works on different materials and colors of materials.  The square is cut and the face is engraved.  The laser also engraves wood!  I am quite exuberant at these impressive results!

From top to bottom left to right are offwhite paper (engraving speed was too fast), green fabric, green craft foam, and black craft foam.  I also did a cool zipper/zigzag design on wood.  I love this laser cutter!