Materials and Budget


The project budget was $300. For the balance board, we bought High Density Polyethylene cutting boards for the top and bottom plates. We bought Ultra High Molecular Weight Polyethylene round stock for the feet. We also bought a sheet of 1/8" UHMWPE for the bottom plate of the board, but it was rendered unnecessary by a subsequent redesign.

We bought 200 LEDs, expecting to use 120 of them and to short several of them. Due to power constraints, we used only 60 LEDs in the prototype Cowabunga Board. We also purchased o-rings to hold the feet in place and machine screws to hold the top and bottom plates together.

The single most expensive item in the Cowabunga Board is the force sensors. The set of four force sensors cost $65 with $15 in shipping costs.

Item Unit Price Quantity Total Price
HDPE Cutting Board 1/2"x18"x24" $21.87 1 $21.87
HDPE Cutting Board 1"x18"x24" $48.60 1 $48.60
UHMWPE 0.125"x24"x24" $17.01 1 $17.01
UHMWPE Rod 2.5" dia x 12" $10.46 1 $10.46
FlexiForce A201 Force Sensor, 4 Pack, 0-100 lbs, 8" standard length $65.00 1 $65.00
LEDs, blue, 5mm, pack of 100 $7.00 2 $14.00
1/4-20 flat head socket cap machine screws, 3/4", 50 count $8.98 1 $8.98
O-Rings, 2.625" OD, pack of 10, code -331 $8.40 1 $8.40
SUBTOTAL $194.32
Shipping $28.13
TOTAL $222.45