So this Lazy Old Geek has too much free time. I recently purchased a Laser Cross (It projects a cross). I wired up a constant current power source and mounted it on a camera tripod.
Uses: Well, I mostly use it for aligning stuff on my drill press but it could also be used for hanging pictures, big screen TVs, house framing and remodeling.
It could also be adapted for a camera for those panorama shots or recording videos.
I had a block of wood with a camera mount (1/4” x 20). The laser was tie-wrapped to the side. Being Lazy, the hard part was getting the tripod level. Now my part time workshop is my part time bedroom and it has carpeting. Theoretically, you can adjust the three legs to get the tripod level. Well, I decided to make an adjustable platform that is easier to adjust.
So I decided to make an adjustable base with a swivel platform. I had an old CD player and plenty of CD cases to hack up.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Parts Lists
Parts List Laser Assembly
650nm <5mW Laser Cross Module Diode $4.37 ebay
The laser diode is a HLM1230.
I made my laser drive current source using this:
Parts List Laser Current Source
Optional: 6 x AA battery holder with 2.1mm plug AdaFruit.com $5.00
LM317 regulator $0.24 TaydaElectronics.com
100 Ohm potentiometer $0.21 TaydaElectronics.com
1N4001 diode $0.01 TaydaElectronics.com
10uFd 50V capacitor $0.03 TaydaElectronics.com
47 Ohm resistor $0.01 TaydaElectronics.com
(used instead of the two 10 Ohm resistors)
PCB I used a hunk of the following:
5* Breadboard Bread Board Prototype 432 Points 5*7cm$1.39 ebay
Did not use a pushbutton
I am not going to go into the details of making the Laser drive current source as it is explained in the above website.
The HLM1230 Laser Diode is designed for 25mA or less. This is how I determined the 47 Ohm resistor value. (See picture)
Parts List Tripod Mount
2 scrapped music CD cases
2 scrapped CDs (I used a regular and a mini)
1 scrapped music CD player mechanical assembly
1/4” x 20 nut
Miscellaneous 6-32 and 10-32 hardware
3 10-32 hex jam nuts
1 hot shoe bubble level $1.59 ebay
2 inches 5/16" vinyl tubing, 5/16" i.d. (internal diameter) I got mine at Home Depot.
Step 2: Laser Safety and Information
Any laser you buy will have a DANGER sticker similar to this one. The particular laser that is I am using is 5mW. The typical laser pointer is 1mW. Now I’m haven’t researched laser safety that much but as I understand it, even a 1mW can damage the eye if looked at directly. This one is five times more wattage so use carefully. Do not aim it at a person or animal.
Some readers may wonder how the cross is generated. Search Ebay.com for this: 650nm <5mW Laser Cross Module Diode Some of the pictures (See picture) show that this module actually projects a red cross. This is created by a special lens used in this module. You can adjust the orientation by rotating the lens mount.
By the way you can get lens that also generate lines or multiple lines and some other patterns.
Step 3: Tripod Mount
I started with two music CD cases. (See picture) They seemed to be fairly sturdy but not too heavy and about the right size.
Note: The plastic is rather fragile to work with. I ended up with a lot of cracks.
Design: I decided on a three point design. The base CD case is attached to the tripod. The upper CD case has a fixed pivot point in one corner (Upper left). The upper right and lower left corners are adjustable with screws to 'level' the upper CD case.
All the camera tripods I’ve seen use ¼ x 20 bolts.
For the base, remove the cover. (See picture) If you carefully bend the little tabs, it will pop off.
Using a ¼”drill bit, carefully drill a hole in the middle of the CD tabs.
Using an Xacto or other knife, carefully remove the CD insert (See picture) from the plastic base.
Put a ¼ x 20 bolt through the bottom and a nut on top.
Epoxy the nut to the plastic base. Don’t use too much, like I did so the CD insert piece didn’t fit very well.
Snap the CD insert back in so that it can conform to the epoxy and strengthen the whole assembly.
I used 10-32 hardware for the standoffs.
Tape the two CD cases together.
Drill three 11/64” or 3/8” holes more or less centered in the area between the edge and the CD indent through both cases about 13/16” from the hinge side and 9/16” from the top and bottom.
In the bottom case, for the pivot corner, drill the hole with a 3/8” drill bit through the bottom two layers but not the cover.This way the pivot bolt will only have a single layer of plastic for the nut to tighten.
Insert a 10-32 x 2” bolt in the bottom case pivot hole. It should go through two layers of plastic and stop at the cover. Put a nut on it and tighten carefully. (see picture)
Put a 10-32 hex jam nut on the bolt upside down so that the flat side is up. Screw it down about a ½”. This will be the pivot resting point for the top cover.
Insert two 10-32 x 2” bolts through the other two holes in the bottom case.
Place a washer on top and put two 10-32 hex jam nuts on them. Screw them down loosely. These bolts will be adjusted to level the top case.
Step 4: Top Case
Take the cover off the top CD case and remove the CD Insert.
Place the bottom piece on to the three bolts.
Place a nut on the pivot point and screw it down loosely.
Place some CDs in between the two cases so that the two cases are parallel.
Do not hot glue the pivot nut. Put nuts on the other two bolts and hot glue the nuts to the case staying away from the bolts.(See picture)
Put the CD insert back on.
Okay, so I wanted to be able to rotate my laser cross. So I had an old music CD player that I’d cannibalized for parts but I still had the CD mechanism. I attached it to the top CD case cover so that the CD was about over the center. It had three rubber mounts so I drilled some holes for 6/32 flat head bolts and attached it to the top. If you want to do something similar then improvise.
Now because the pivot bolt is sticking out I had to put the top over that bolt then snap the tabs in.(see picture)
Step 5: Attaching Laser
I used an old regular CD and a mini-CD.
Ok, here is my funky laser mount. I took a strip of aluminum from an aluminum "For Sale" sign and bent it around my laser housing in a kind of ‘P’ shape. I drilled a 9/64” hole in this bracket so that when a 6-32 screw and nut are used it will clamp down on the laser housing. I drilled a 9/64” hole in the mini-CD so that the laser will be about through the middle of the CD. I also used a rotary tool (Dremel clone) to open up the mounting hole. Then using a short flat head screw through the bottom of the mini-CD, I attached the laser.(see pictures)
Since the screw sticks out, I drilled a corresponding bigger hole in the regular CD to accommodate the head of the screw. For now, I just used some double sticky tape to join the two CDs together. Now the whole assembly can snap onto the CD mechanism on top of the two CD cases.
Step 6: In Action
For the two adjustment screws, I cut about an inch of 5/16” vinyl hose for each and slipped it over the bottom of the screws.
I put the bubble level on the CD.
Put the whole assembly on the tripod. Adjust the tripod legs so that it is fairly level.
While watching the bubble level, twist the vinyl hoses until the bubble is in the center.
Once the assembly is level, you can adjust the cross to a vertical-horizontal orientation by rotating the lens cover of the laser. I used a level to make sure it was horizontal.
To verify the whole assembly, you can rotate the CD and make sure the bubble remains centered.
Another method it to project the laser cross on a wall. Rotate the CD assembly; the horizontal line should not move up or down.
I noticed a little variation in my setup. There's some play in the CD and my tripod is on carpet. But for my purposes, it is close enough.
I have used this to align stuff in my drill press. For instance, if you are drilling multiples holes in a piece of PVC and want them all through the center, use this laser cross.
So this works pretty good. Of course, I am an electronics geek so want to automate it with an Arduino. But alas that's a future Instructable.