Microprocessor-controlled apparatus adaptable to environmental changes
US5007520A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1989 |
| Grant date | Apr 16, 1991 |
| Priority date | — |
| Expiry date | Jun 20, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D5/08
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A microprocessor-controlled electronic coin chute is designed for use in a coin telephone station and adapted to operate over an extended temperature range while making coin acceptance/rejection decisions that are both rapid and accurate. Within the coin chute are a pair of coin quality sensors designed to measure a different property of a coin such as composition and size. Each coin quality sensor comprises a series-connected pair of coils placed on opposite sides of the coin path. These coils are part of an oscillator circuit having a maximum frequency when the coin is positioned between them, and an idle frequency otherwise. Idle frequency measurements are made each time an associated telephone switchhook is operated. The measured idle frequency serves as a temperature indication which, together with a stored program, is used by the microprocessor to establish acceptability limits for each coin in an allowed set. The stored program includes a predetermined functional relationship between acceptability limits and idle frequency for each allowable coin. New acceptability limits are calculated immediately after the idle frequencies are measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.