The Nirvana Machine uses a battery screwdriver to tumble beans over a camp stove. Unlike commercial machines, the basket is tilted and open-ended, which makes it easier to load the beans and to see and smell their progress during roasting.
When you roast coffee, sugars caramelize, water vaporizes and makes the beans expand, and aromatic compounds are produced, including the ones shown above. The compounds develop at different rates, so varying the roasting time and temperature lets you balance which you want more or less of, to determine the resulting flavor.
The Version 1 basket was a cheap strainer, but the beans broke through that and caused a fire!
MATERIALS
[A] 1′ square stainless steel wire cloth, .025″ wire diameter Do not substitute. McMaster-Carr part #9238T523 mcmaster.com
[B] Unpainted aluminum flashing 10′×10″×.010″
[C] Battery-powered screwdriver I used a Black & Decker AS600.
[D] 1½″×¼″ piece of aluminum, at least 4″ long Cut from McMaster-Carr part #6023K231
[E] 
aluminum bar, 3′ long Cut from McMaster-Carr part #8975K833
[F] A few inches of adhesive foam weatherstripping
[G] Single-burner propane camp stove The Century 2058 Trail Scout is best.
[H] Simple on-off (SPST) switch RadioShack part #275-701
[I] 2′ insulated wire, 22-gauge minimum Telephone cable wire works well.
[J] Twin D-cell battery holder RadioShack #270-386
[K] D-cell alkaline batteries (2)
[L] Two pieces of acrylic or other hard plastic, at least 3″ square each, one 
thick and the other ¼″ thick Cut from McMaster-Carr part #8589K41 and #8589K81
[M] 
brass brazing rod From a welding supply house
[N] Scrap plywood 8″×8″
[O] Matching 1″ long carriage bolt, washer, and knob, ¼″ threaded
[P] Matching 
long machine screws, washers, and nuts, 6-32 threaded (16)
[Q] Matching 3½″ long hex-head bolt and nut, ¼″ threaded
[R] Uninsulated wire, 24-gauge solid McMaster-Carr part #8870K16
[NOT SHOWN]
Standard 16.4 oz disposable propane cylinder ¼″ long machine screws, 6-32 threaded (4)
Wood screws, ½″ long flathead #10 (2) and ½″ long #6 (8)
Scrap 1×8 lumber or plywood At least 18″ long
Scrap wood block About 6″ cube
8″ wood or plastic dowel, ¼″ diameter
Wood glue or 5-minute epoxy
Paper For templates and caution label
See a list of tools for this project at makezine.com/08/roaster.