Home

Workshop   Solutions

The Electric Wheel Chair Power socket

THE PROBLEM: A person confined to an electric wheel-chair needed to operate his laptop computer with speech-software during school hours. The computer battery did not have sufficient capacity to meet the demand. To be heard in class, powered speakers were needed, which further diminished operating time. A portable solution was wanted so the speech software could be used anywhere.

The Solution: The wheel chair uses two 12 VDC high capacity batteries wired in series. A standard cigarette lighter socket tapped power from one of the batteries and mounted on the top of the battery case. Tapping directly to the battery avoids both electrical noise generated by the chair controller and need to modify the chair charging system. A standard 150 watt 12VDC-120VAC inverter was plugged into the cigarette lighter socket allowing the chair battery to be used for the computer. A wooden box was mounted on the back of the chair to hold both the inverter and the power supply. The computer vendor did sell 12VDC power supplies, but these were much more expensive than the standard inverter. This could also be used to power a cell phone or similar low-powered electrical device. The speakers had to be mounted such that they faced forward, were easily removable, but did not extend past the chair wheels when mobile. I used a wooded box that speakers dropped into, yet were easily removable. The front and back were cut out for the grill and wires. The box was mounted on a metal frame made from 2 pieces of ¾" flat steel stock. One piece was bent 90 degrees to support the speaker box. The two frame pieces were welded to a 3" hinge that allows speakers to swivel behind the chair when needed. The frames were attached to the chair using stainless hose clamps.

Home

Workshop    Solutions