Photo-gate timer: Difference between revisions
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Created page with "===Specifications=== *Run on a battery. *Include a multi-character display, at least four digits. *Include a power switch to save the battery. *Use a breadboard so it can be m..." |
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===Circuit=== | ===Circuit=== | ||
===Components=== | ===Components=== | ||
===Power supply=== | ===Power supply=== | ||
Using a 3V LCD display will require us to use one 3V coin cell or two AA or AAA batteries. Or, we could use a 5V phone charger with a 2V power diode, or find a rarer 3V plug-in power supply. | |||
===Program=== | ===Program=== | ||
Revision as of 14:08, 22 February 2014
Specifications
- Run on a battery.
- Include a multi-character display, at least four digits.
- Include a power switch to save the battery.
- Use a breadboard so it can be modified.
- Timing of periods of at least 10 s accurate to 0.01s
Circuit
Components
Power supply
Using a 3V LCD display will require us to use one 3V coin cell or two AA or AAA batteries. Or, we could use a 5V phone charger with a 2V power diode, or find a rarer 3V plug-in power supply.
Program
- Clear the display
- Loop.
- Watch for a break in the first gate. If so, reset counter and continue to next loop.
- Loop.
- increment a counter periodically. Use a period of 10ms or less.
- Watch for a break in the second gate. If so, continue to the next section.
- Convert the counter to a proper number, if necessary.
- Display the number
- Return to the idling loop.
