I used conductive spheres to shuttle electric charges between the poles of a high voltage (HV) DC source. This shuttle assembly was made from two, foil-covered spheres joined by a non-conducting, plastic tube. The assembly was sandwiched between two stationary, dumbbell shaped electrodes. When the upper dumbbell was grounded with respect to the negatively charged lower dumbbell, the shuttle began to bounce between the HV poles with a clacking noise as charges were transferred from the lower to the upper electrode. This rocking motion completed the HV circuit.
I powered the project with an electronic air ionizer purchased at a rummage sale; but other sources of HVDC, such as a Van de Graaff generator could be used to rock this clacker. For a video clip about the project, click here: http://www.youtube.com/watch?v=eQrXRCu066c .
If you choose a commercial air ionizer as the power source, use a model powered by a low voltage AC adapter. A line powered ionizer can be a serious shock hazard!!
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Step 1: Tools & Parts
You will need: white and CA glues, cellophane tape, small hammer, scissors, a ruler, a small metal saw, an electric hobby drill with 1/8" and 1/16" bits, an electrical continuity tester as well as the following items. Remember, for this type of project there's always room to improvise.
A. Shuttle Assembly
Spherical Core Forms (2) Newspaper sheets to make ~1" dia balls.
Al Foil Foil (for wrapping hot heros to go) to
Dielectric Connecting Tube (1) Just a geeky name for a 5" x 1/8" non-conducting,
plastic straw (or use a 1/4" dia empty ball point
pen cartridge for better support).
Axle (1) paper clip.
B. Stationary Electrodes
Spherical Core Forms (4) Newspaper sheets to make ~1-1/2" dia
Al Foil Foil for covering cores.
Connecting Rods (2) 6" x 1/8" lengths from a heavy duty coat hanger.
C. Stationary Electrode Mounts
Dielectric Support Columns (4) 5-1/2" x 1/4" thick shake straws or something similar.
Stand-offs (4) Small plastic or stryo thread spools w/1/4" center hole.
Mounting Hardware (8) 1" x 18 gauge nails.
D. Shuttle Mounts (2) 4-1/2" x 1/2" dia, x-tra thick, smoothie straws or
E. Project Base (1) Whatever works; try fast food take-out tray or 1/8" cardstock
cut to appropriate L&W.
F. PowerSupply & Accessories
HVDC Source (1) Small, commercial electronic air ionizer, such as the Micronta
Air Purifier (Radio Shack cat. no. 63-643) as shown
in picture or Van de Graaff, etc .
Input Terminals & Leads (2) Color coded, plastic push pins & insulated wire.
Step 2: Prepare 1st Core
Rip a full sized page into 1/4 sheets. Apply glue to one side and squeeze into a tight ball. Use just enough glue so the newspaper is moist but not dripping. (Too much glue? Just wrap another dry sheet around the ball.) Repeat this step until you have built up a 1-1/2" dia core; about four to five sheets are needed.
Continue rolling and squeezing the core thoroughly until the glue completely saturates the layers of newspaper. Squirt glue under any loose corners on the surface. After 20 - 25 min of smoothing out bumps, the core should feel really compact and look more or less spherical.
Step 3: Complete Remaining Cores
Step 4: Assemble Electrodes & Cover With Foil
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Here's better approach: cut a large square of foil and wrap it tightly around the sphere and rod assembly; it's not as neat, but it works. Also, the foil keeps the assembly together until the glue dries. :>)
Step 5: Check Electrical Contact for Stationary Electrodes
Both foil-covered assemblies should have minimal resistance as indicated on the tester.
Step 6: Assemble Dielectric Supports
Step 7: Attach Supports to Stationary Electrodes
Now repeat these steps w/the upper stationary electrode. Adjust the height of the straws in the spools as needed to make the entire structure level on a flat surface.
Step 8: Mount Stationary Electrode Assembly
Step 9: Charge Shuttle Asembly
Straighten a paperclip to make the charge shuttle axle. Insert one end of the clip perpedicularly through the hole. I made bases for the shuttle mounts from 1/2" x 1/2 dia wood plugs cut from a dowel and inserted into one end of each straw.
Important Note: the shuttle assembly must be equidistant from upper and lower electrodes so that each sphere of the shuttle contacts a stationary sphere simultaneously (it's embarrassing to say how long it took to [almost] achieve this requirement! :> o). Once you determine the optimum shuttle height and repositioned the stationary electrodes as needed, hold the mounts in position and mark the location; drill a 1/16" hole in each straw to accommodate the axle. Glue mounts to the base. Lastly, insert the shuttle-axle assembly between the mounts and lock the in place by bending axle ends at 90 degree angles.
Step 10: Final Assembly & Power on Procedure
Initially, when power was applied, the shuttle was as stiff as an arthritic knee in the winter. The holes in the shuttle mounts were binding the axle; one charge collector keep bumping a support column and the other collector still wasn't contacting the stationary electrode.
After correcting these problems, the shuttle began to oscillate after slight push but without that trademark CLICK-CLACK sound; so on to version 2.0...
Step 11: The Clacker 2.0: Upgraded, Accessorized & Wireless!
Both stationary and shuttle electrodes for the 2.0 version were made from birch wood balls (http://www.craftamerica.com/wood_balls.htm) sprayed with conductive metal paint (http://www.lessemf.com/). Connecting rods between the stationary electrodes were sheathed with heat shrink to reduce corona loss.
Quarter inch acrylic rods with a painted wood ball glued to each end supported the stationary electrodes and preserved the project's dumbbell design. Dielectric and shuttle assembly mounts were similar to those in the budget model. Color-coded, HV leads were used to apply power from the ionizer in a base made from a discarded jewelry box.
I accessorized the project with four ceramic insulators as stand-offs and used a 1/4 W neon bulb as an power-on indicator. The yellow furballs were placed near the lower electrodes to indicate electric field intensity the same way long human hair flies upwards near a VdG discharge terminal. But these guys with their buzz cuts weren't very useful. :>(
The Clacker 2.0 can be powered by this homemade VdG (output: ~50 kV @ 2 uA) pictured here; or the commercial air purifier (output: ~7 kV DC @ 35 uA) shown in Step 1. Power transmission was completely wireless using a VdG. BTW, a ground return connection to the VdG chasis wasn't needed. The shuttle rocked from the ion stream that passed through the air to the small antena (made from a headless finishing nail) on the upper electrode.
If you want to use the 2.0 clacker as a metronome, adjust shuttle tempo by changing the distance between your VdG and the antena. Slight changes in horizontal distance will produce big changes in tempo so you can keep the beat to those various Old School jams from back in day.
Rock On!! : D