Motor motion detection circuit
US5216533A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 3, 1992 |
| Grant date | Jun 1, 1993 |
| Priority date | — |
| Expiry date | Jan 3, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B26/105
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A circuit for detecting the motion of an oscillating motor driving a mirror for causing a light beam to scan. The circuit is included in a laser scanner for illuminating and reading bar codes, and detects the presence of conditions which prevent the motor from moving, such as a broken wire in a winding. The motor has two windings which are driven by a logic device to cause the motor to oscillate between two extreme angular positions. Each winding has two legs. The voltage on at least one of the legs is monitored when the leg is not being driven by the logic device, to detect the presence of an electromotive force voltage produced by motion of the motor. The monitored voltage is conditioned and transmitted to the logic device. In one embodiment, the monitored voltage is sampled twice and the two samples compared to provide an indication whether the motor is moving.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.