STEPPING UP TO NEW ENERGY

The potential to recover the energy in the human stride and translate it into more efficient transport has long intrigued geniuses, like Engineer-of-the-Century and NEWENERGYNEWS' friend Paul MacCready.

Making energy from the sole
April 21, 2007 (AP via KATC3-TV)

WHO
Assistant professor of electrical engineering Ville Kaajakari; Defense Advanced Research Projects Agency (DARPA)

WHAT
DARPA awarded Kaajakari $50,000 to develop a shoe that recycles the energy from the stride of the wearer into a battery cell.

WHEN
The grant is for 6 months’ research.

WHERE
Kaajakari teaches and does research at Louisiana Tech University.

WHY
- A stride forces significant energy down as the foot falls. Kaajakari’s design uses piezoelectric polymers in the heel of the shoe which absorb the energy when pressure is applied and release voltage. A previous similar experiment failed because it did not use piezoelectric polymers.
- Theoretically, three days of walking is enough to recharge a cell phone battery that holds its charge for three days.
- Problems remain. Wiring from the shoe to the battery cell is one. Kaajakari is using Nikes for experimentation because the company already has a model with a sensor for the iPod in it.
piezoelectric polymers
QUOTES
- Kaajakari: "In this, the voltage is generated when a user steps on the heel…The polymer aspect is a key here: Our technology is simpler, cheaper, and gives 10 times more power…"
- Kaajakari:"The military is very interested in low-power performance…Their interest is in having everything use as little power as possible."