I need a laser level, but I don't need one very often so dropping a few hundred on something I might use once in a while was just not going to happen.
That still left me with out a laser level, and the only solution was to make one.
So with nothing more than a few hand tools and some odds and ends from my junk pile I got to work.
For my automatic laser level I decided to use a gimbal and because I wanted to make the most accurate device possible I needed to make it as smooth and precise as possible.
What I needed was a cheap and highly precise bearing assembly already made. That's when I hit on the idea of using the bearing assembly from a HDD.
Step 1: Manufacturing the gimbal - first axis.
First job was to strip the HDD down to its components.
For this I used a Torx drive 8H and 6H.
Once the drive was striped I looked at how to use the motor assembly as part of the gimbal.
Whats first noticeable about the drive motor is that the are threaded holes on a wide drum, this will make a good seat for attaching my aluminum angle.
Using a peace of 25x25x1.5mm aluminum angle I drilled holes to match the threaded holes on the HDD motor, this was done using the collar that holds the HDD platters in place as my drilling template.
Step 2: Manufacturing the gimbal - second axis.
For the second axis I used the bearing from the read and write arm of the HDD.
I cut a bolt down to size and using a couple of nuts as spacers and some heat shrink to keep the nut centered in the bearing I assembled the second axis on to the aluminum angle.
Now I was ready to assemble the second axis to the first axis to make my gimbal.
Step 3: Manufacturing the gimbal - laser pendulum.
The laser will be suspended in a pendulum from the gimbal.
I used 19mm aluminum square with an MDF core hammered in for a snug fit. Using a set square I marked the center on both sides and decided were I would drill my holes.
I also but in a rivet nut for the balance adjustment bolt. I didn't crush the nut just hammered it in to a smaller hole and it holds fine.
TIP: if using a hand drill and you want the hole to be mirrored on the other side of the tubing, drill pilot holes on both sides before drilling with bigger bits, this should help keep things square.
Step 4: Fitting the laser
My old laser pointer, finally found a use for it.
Step 5: Making the enclosure.
I used 3mm aluminum composite panel for the box and a second HDD for the side wall.
The aluminum panel are off cuts I get from a sign writing company next to were I work, I also used a reciprocating drop saw to cut 2mm deep channels that allowed me to bend it around the HDDs to form the box.
It was at this point I decided to use a round spirit level to make things look cool and also help get the box near level, If the box is to far out of level the automatic laser level wont shine out of the hole in the front.
Step 6: Wire it up.
For the wiring I needed something thin and light, my original plan was to use wire from an old network cable but that turned out to be to stiff and affected the movement of the gimbal badly.
My partner suggested her old iPod headphones might be better, and was she right. iPod headphone wire is super thin, super light and super strong and was super perfect for this application as it did not affect the movement of the gimbal at all, I just needed to leave a loop of wire to allow for free movement.
To solder iPod headphone wire you need to remove the coating to allow for soldering. For this I used a lighter. Just hold the end of the wire over the flame for a second and there should be a brief flash as the coating burns off, now you should be ok to solder.
Step 7: Calibration.
This is the final step.
To calibrate the laser level there is a bolt and screw that adjusts the angle of the pendulum by shifting the center of gravity, over 20 meters a fraction of a turn can translate into an big angle.
So how to calibrate, well a clear plastic tube filled with water (food coloring helps for visibility) will give a perfect level over a great distance, so with that in mind I set this up in the garden.
I marked a target line on stake at the back of the garden and a target line on the front gate post using the water level.
Now to set up the laser, I lined the laser up with the mark on the front gate post and then turned the laser until it hit the stake in the back of the garden, it took a while to get them lined up with the laser sort of nicking the edge of the gate post but with enough light hitting the stake in the back.
By turning the balance screw in small increments and having to raise the laser up as I went I was able to get both targets lit at the same time over about 20 meters.
So I now have a Automatic laser level which I know works, and with a few improvements like a base screw so I can attach it to my try pod I hope it will be a fun tool to use.