Tuning in Your Tennis Shoes
The principle that increases the sensitivity of the old superregenerative receivers is now being applied to help keep seasoned citizens more firmly on their feet. Research has shown that as you age, the minor correction signals sent to your brain to counter tipping are often significantly reduced, causing the characteristic swaying or even falling over. Just as the receivers of yore used a kind of "tickler voltage," often random noise, to peak its sensitivity to a small signal, specially designed soles are being developed that increase the sensitivity of the brain to minute corrective foot movements. The technical term is stochastic resonance. These soles have hundreds of vibrators that, when tuned to the wearer's natural foot movement frequency, can usually eliminate the problem. They should be in stores by the middle of the decade.