To go with my Doc Hadacoff character, I needed a medical scanner. I wanted it to be similar to Doctor McCoy's Scanner
in the original Star Trek TV show. The scanner is made from a modified $.97 Walmart garden light. The original white led is replaced with a Schottky diode and color-fading RGB led. The diode and capacitor allows enough rectified current to drive the RGB led directly. The RGB led then illuminates a vacuum tube to complete the effect.
Step 1: Walmart Garden Light
I found the garden light at Walmart for 97 cents. The section with the solar cell and light makes up the scanner.
Step 2: The Components of the Light
Remove the main body of the unit from the clear plastic lens. Locate the 3 screws on the main body.
Step 3: Alternate Design for Scanner
You can make a decent looking scanner by using the plastic lens instead of adding a vacuum tube. Wrap the black plastic body of the light with a piece of leather (Tandy Leather
). Use a knob on the end for use as a "control knob".
I wanted more of a Steampunk look, so I used the vacuum tube, copper and brass approach.
Step 4: Open the Light
Start by removing those 3 screws that hold the light together. Carefully open the unit. You will see a tiny pc board with the white led attached. Replace the led with a diode, capacitor and a RGB color-fading led.
The PC board is a high frequency oscillator to step-up the voltage from a single cell. The circuit is similar to the popular Joule Thief
, found on the internet.
Step 5: Replace Original Led
Cut the leads to the original led so as to leave wire stubs to solder to. Remove the original led and replace with a color-fading RGB type. You can get these from Electronic Goldmine
The capacitor in this example is a ceramic 4.7 uF. You can use a electrolytic type as long as polarity is respected. Note the polarity of the led and connect to the capacitor in parallel. Connect the negative end to the negative wire stub of the original led. Series connect the Schottky diode from the positive stub to the positive capacitor/led end. The value of the capacitor is not critical. Any value from 1uf or more should work. Use a 10v or more rated voltage capacitor.
I used a Schottky diode because of its low voltage drop and high speed characteristics. Suitable diodes are 1N5819, MBR110 or perhaps other diodes.
Schematic and photos are shown on my Steampunk Scanner
Step 6: Body of the Scanner
Now that we have a colorful light source for the scanner, lets build the body of the scanner using a vacuum tube. I used a 1 inch copper pipe cap to support the vacuum tube. A hole is drilled into the top of the cap to fit the base of the tube. The light from the RGB led shines into the base of the tube. A 1/2 inch copper pipe cap is used to support the tube with a bent strip of brass sheet attached to the bottom cap.
A large brass washer was cut and silver-soldered to the copper cap to attach to the base unit. You can use the original plastic lens as a pattern for the base.
You can get the copper caps and brass sheet from Home Depot or Lowes.
Step 7: Scanner Viewed From Below
To attach the scanner part to the base, I found a large brass washer similar to the thickness to the mounting tabs of the original plastic lens. Cut and roughly shape the washer and attach to the pipe cap with silver solder. Regular solder may work, but will not be as strong as with the silver solder. After soldering, you can use a sander to finish it up.
Use the original lens as a pattern to shape the base. You can add tape if you need to build up the thickness. The new base should fit the light base snugly.
You can see in the photo the hole used to fit the tube and allow light from the led.
I found at a craft store (Michaels) an assortment of "gears" to act as a gasket for the tube and for the dial. These help to add to the Steampunk look of the scanner.
Use a 1/4 inch diameter, 1/2 inch long spacer to attach the knob to the scanner body.
Step 8: On/Off Switch
To turn off the scanner, you can insert a tie wrap in a slot on the base unit. This inserts between the battery contact and the holder inside the base.
Step 9: Details
Attach the leather trim to the body of the base with double-sided tape or contact adhesive. Use a copper strip to cover the seem of the leather.
Step 10: Other Tubes to Use
You can use other tubes instead of the example I have shown. Above is a photo of some acorn tubes. You can also use items such as glass test tubes filled with clear plastic chips.
Step 11: View in the Dark
The tube will have a nice glow in the dark with changing colors.
Step 12: Have Some Fun With It
I used the scanner while playing the character Doc Hadacoff with my Elixirator, a cocktail-mixing machine. You can get details on how I built the Elixirator by viewing the instructable
. After-all, any doctor that travels back in time needs his scanner.