This Instructable is going to show you how to add a laser line to your dart board so you don't have to put a strip of ugly tape on your newly carpeted game room floor.
I had already built a dart board cabinet for my basement and wanted to find a way to add a throwing line to the floor without permanently attaching it to the carpet or floor.
I decided a laser line would be the perfect way to do this since I already had power to my dart board cabinet for the dart board itself and the lights in the top of the cabinet.
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Step 1: Tools and Materials You May Need
I used a 10 mW red laser module with a line lens. I ordered it online for about $12.00 plus shipping.
This laser module came with a regular "dot" lens. I added a line lens for $3.00. The line lens had roughly a 40 degree display angle.
I found a cheap Game Boy 3 volt transformer to power the laser at Radio Shack.
The only other materials I used were a binder clip and a #8 wood screw. The binder clip is used to hold the laser module and the wood screw attaches it to the dart board cabinet.
The tools I used on the project were as follows:
- cordless drill
- scroll saw for making a slot in a piece of wood.
NOTE: If you plan on using any tool for a project please make sure you are familiar with the tool and all of the dangers associated with it. If you are not familiar with a tool then you should ask someone who is to show you the proper way to use it. A lot of communities have classes at local colleges on the proper use of tools and machinery. There are also local woodworking clubs that offer classes at very reasonable rates for beginners. I highly recommend using these resources for your safety and for the most efficient use of the tool.
Step 2: Mounting the Laser Module
Now we need to decide how to mount the laser to the cabinet. Commercial mounting clamps are available, but I found that a regular paper binder clip works well and holds the laser module tight. I already had a cover plate that hid the wiring for the LED light bulbs in the top of the cabinet so all I needed to do was find a place that wouldn't interfere with the light bulbs, mount the laser, and cut a slot in the cover plat to let the laser light shine through.
You can mount the laser above or below the dart board. If you are mounting the laser near the dart board then try to mount it as low as possible so there is less of a chance of people getting blasted in the eyes with the laser when they are close to it.
I chose the upper left corner of my cabinet since it was an unused area, had plenty of material to drill into for mounting the laser, and was off to the side of the center of the cabinet. I also wanted the laser module in a place where it wouldn't get hit by a dart and get broken or knocked loose. If the laser is positioned above the dart board in the center then when shorter people walk up to the center of the cabinet to remove their darts they will get blasted in the eyes with the laser light. If the module is off to the side then there is less of a chance of getting hit in the eyes with the laser light.
My laser turns on when I turn the power on to the cabinet. One push button switch turns power on to the dart board, cabinet lights, and the laser.
Make sure you don't mount the laser in a place that could shine into people's eyes and cause damage. My kids are a little older now and they know better than to look into the laser light.
Step 3: Positioning the Laser
Once you have the laser mounted in your cabinet you just need to focus the beam and line it up with the official toe line distance for your dart board. I used blue painters tape to mark the line position on the floor temporarily. Then I focused the lens on the laser module to get a crisp line at the distance to the toe line. Once the lens is focused then you need to rotate the laser module and lens within your mounting bracket (mine is the binder clip) to get the correct line orientation. This can take a few minutes as you might have to adjust a few times. Once you have the laser lined up and focused you can remove the blue painters tape from the floor.
Step 4: Running and Hiding the Power
The power for the laser module in my cabinet comes from the extension cord that I have running to the top of the cabinet. My 3-volt transformer plugs into the extension cord and is small enough to fit in the enclosed area at the top of my cabinet. The wiring is enclosed with a cover plate that is held in place with four small rare earth magnets that are epoxied to the back. Once I had the laser module in place I just had to cut a slot for the laser light to pass through. The narrow slot also helps narrow the output beam from the original 40 degree angle. See the pictures for more details on the cover plate.
Step 5: Play Some Darts
Now that the laser line is showing you where to stand you can grab a cold one and play some darts.
The picture shows how the line looks although the line appears brighter in person than it shows in the pictures.