A homemade arc reactor of Tony Stark is illustrated in this mod which uses surface mount LEDs and acrylic ring to build the movie replica prop. An old heart rate monitor strap is used to attach the reactor as shown in the image below. It is comfortable to wear for longer hours at a time and is lightweight with a 3V battery pack as the power source. Under normal office lighting conditions, it easily shines through a t-shirt and at night, it is very bright.

There are two ring assemblies of surface mount LEDs that comprise the miniature arc reactor. A diffused glow is created by one central LED that is covered by lens while 10 are arranged in an acrylic ring. The LEDs are beating to the rhythm of the heart due to an old heart rate monitor that is strapped to the chest.

To start with the backplate, a general plan has to be drawn to figure out how everything will be connected. The drawings are just to be used as a guide in order to obtain the correct proportions during the final assembly for fitting everything. The patterns are drawn on paper and then glued to the sheet metal or sheet plastic. The edges are filed and used sandpaper to smoothen them.

Cutting a 4” diameter disc from PCB material begins the outer ring/backplate assembly. A couple of solder pads on the center for soldering down the LEDs were cut as well as 2 copper traces. This makes it easy for the surface mount LEDs to solder to the copper traces. To make sure the LEDs are facing the same direction, they are sitting directly under a clear acrylic ring and spaced 36 deg. apart. The LED copper traces were connected to the center solder pads and 2 small holes were drilled. For the 3Vbattery, some wires were soldered from the back of the board.

Some thick plastic sheet was cut for the outer ring. Evenly spaced at 36 deg. intervals around the ring are the ten allen head bolts. A glue gun attaches the outer ring to the PCB backplate. In order to keep the circuit from being shorted out when the remaining parts are installed as well as help diffuse the light and protect the LEDs, a bead of hot glue run over the copper traces and LEDs.

A clear ring that is held by a frame is the inner ring which is cut from clear acrylic sheet. Placed around a central ring to form the lower spider frame are the 20 arms that are cut out and bent. The clear ring should fit into the slots cut into the spider arms. To carefully trim the opening to fit the acrylic ring, a small sanding disk with a Dremel tool is used as the easiest way to trim the opening in the spider.

After the clear ring has been placed into the spider frame assembly, 10 little brass tab thingies will sit on top of the clear ring then wrapped with copper wire. The brass tab thingies should be about the same width as the clear ring and over the edges of the spider arms, the 4 little tabs should just stick out. The image of the inner ring assembly is shown below.

The top ring assembly is made just like the spider frame assembly wherein a central ring is made from aluminum but could also be made with silver-painted plastic. As seen below, a nut on the backside is present so the assembly stays put when everything is put together in the final assembly. There are also 3 bolts that go through the spider and slotted ring.

The final assembly is shown below which would require plugging in the battery and ensuring all the LEDs light up. By lining up the 3 bolts, the center top ring assembly is mounted to the inner ring assembly and tightened until the bottom of the top ring assembly sits just above the inner ring assembly.