As part of the "Make it Real Challenge" I thought I would revisit my designs for the MkII and create a brand new design to share with the Instructables community. This new model, which I've dubbed the LightHammer Mk 2.5 (see images 1 and 2), uses the same components of the MkII but adopts many of the design concepts from the MkIII. By following these instructions you will be able to build your own LightHammer and begin creating your very own "marteaugraphs".
Then lets get started!
Step 1: Materials and Preparation
To construct the body we will be using layers of 1/4" hardwood ply bound together with aluminum binding posts. In total the body will consist of 20 individual pieces cut from a 2ft by 4ft piece of oak or birch plywood (these are the two most common forms of hardwood plywood, but any hardwood species should work). The individual sheets will then be layered together and held in place by 4" and 1.5" aluminum binding posts. A 1/4" sheet of ultra-soft (50Oo Durometer) polyurethane will be used on the face of the hammer to absorb the force of impact and protect the LEDs. When completed the hammer will be 4" wide by 10" long and 5" tall.
[ Note: Most plywood sold at your local big box lumber yard is thinner than labeled. This means that 1/4" plywood is actually closer to 7/32" or roughly .22 inches. The Mk2.5 is designed for these thinner sheets, however it can be adapted to accommodate a true 1/4" plywood by omitting sheet-3 and sheets-19-20. ]
The electric "guts" of the hammer will take the form of a 4xAA battery holder, a toggle switch, a rotary potentiometer, a tilt switch, a 150-Ohm 1/8-Watt resistor and 9 super-bright LEDs. You will also want 22 gauge copper wire (I prefer solid core but braided is fine), ideally in two different colors so that you can easily distinguish between "live" wires and "ground" wires, as well as a spool of solder.
In addition to the materials listed above, you will also need access to a lasercutter, a 1/4" round hole arch punch, a soldering iron, a good pair of wire strippers/cutters, electrical tape, contact cement or similar adhesive and a hot glue gun. While not necessary, you may also find a digital caliper and a "helping hand" magnifier to be useful as well.
[ Note: With laser cutters becoming more inexpensive and consumer friendly, the task of finding a cutter has become significantly easier. A good place to start is with your local maker or hacker space. In my experience these spaces will either have their own laser cutters or will have contact with individuals who do. I have had the pleasure of working with two such groups: AS220 of Providence and Open Lab Idaho of Boise. ]
AI files of all hammer parts along with a full parts list are attached below.