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The basic design is to be based on a Fisticuff which has a ID bit Analogue to Digital Converter (ADS) that can be used to measure the resistor being tested. One way to measure resistance is to use a constant current generator to force a known current through the resistor and measure the voltage across the resistor to obtain the voltage equivalent of the resistance under test value. The resistors to be measured are incorporated in a Bandoleer that is mounted onto the drum of the tester by the user. A Stepper Motor can rotate the drum, so as to move each resistor under the Test Probes.
The Stepper Motor is rotated by the PICK by providing a pulse to the Stepper Motor four windings in a manner that will cause the Stepper Motor to rotate. You will need to do a Google search to find a suitable Stepper Motor step sequence. This should follow the ‘Full Step’ sequence. Details of this Stepper Motor sequence must be included in this assignment report. Once the first resistor has been set up to lie under the Test Probes by the user, four steps of the stepper motor will move the next resistor to be tested under the test probes.
The tester can be started by pressing the Start switch, and stopped by pressing the Stop switch. When stopped, the Start switch can be used to re- start the tester again so as to continue testing. When the tester is first started, if the first five resistors that are tested are found to be outside the В±5% limit a warning LED indicator is to be turned on to indicate that the bandoleer may contain the wrong resistors. Otherwise all resistors are to be tested, and a count of all resistors that fail the test kept.