Difference between revisions of "Continuity Tester"
From Hackstrich
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== Status == | == Status == | ||
| − | * 2018-01-11: Received PCBs and parts, started | + | * 2018-01-11: Received PCBs and parts, assembled and started testing. |
* 2017-12-13: Completed PCB design, sent to OSH Park for manufacturing. | * 2017-12-13: Completed PCB design, sent to OSH Park for manufacturing. | ||
* 2017-12-11: Started putting idea together after spending lots of hours reversing for the DMS project. BOM and schematic done, PCB layout in progress. | * 2017-12-11: Started putting idea together after spending lots of hours reversing for the DMS project. BOM and schematic done, PCB layout in progress. | ||
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* Lasts a long time on a CR2032 or similar | * Lasts a long time on a CR2032 or similar | ||
* Clips or magnets to a board I'm working on to save having another thing to put somewhere. | * Clips or magnets to a board I'm working on to save having another thing to put somewhere. | ||
| + | * No programmable logic, entirely simple analog/digital logic | ||
| + | ** I almost never have projects that don't involve firmware, I'd like this to be one of them. | ||
| + | ** Makes it easier for people to replicate without needing programming hardware/software | ||
== Rev001 Issues == | == Rev001 Issues == | ||
| Line 17: | Line 20: | ||
* LED footprints are backwards (anode/cathode swapped, addressed in ECO B) | * LED footprints are backwards (anode/cathode swapped, addressed in ECO B) | ||
* Beeper/LEDs respond "analogly" due to the capacitor on the TRIGGER line | * Beeper/LEDs respond "analogly" due to the capacitor on the TRIGGER line | ||
| − | ** | + | ** Will add another 555 in the next revision and add a real timer for the latching functionality |
| + | ** Second 555 rather than a 556 so we can have one on always for the sensing and turn the second on as-needed for the beeper, saving battery power | ||
* Current draw idle is a bit higher than I'd like, should try to optimize this further | * Current draw idle is a bit higher than I'd like, should try to optimize this further | ||
* Duty cycle control isn't really useful, should reevaluate need for it in Rev002 | * Duty cycle control isn't really useful, should reevaluate need for it in Rev002 | ||
| + | |||
== Rev001 ECOs === | == Rev001 ECOs === | ||
* A - Trim legs on both jacks slightly to enable them to fit through the holes. | * A - Trim legs on both jacks slightly to enable them to fit through the holes. | ||
Revision as of 00:16, 16 January 2018
I want to build a continuity tester that's fast, tiny, and can attach to a board I'm reversing so I don't need full multimeter when reversing boards away from a desk. The hardware files for this can be found on GitHub at sarahemm/continuity_tester.
Status
- 2018-01-11: Received PCBs and parts, assembled and started testing.
- 2017-12-13: Completed PCB design, sent to OSH Park for manufacturing.
- 2017-12-11: Started putting idea together after spending lots of hours reversing for the DMS project. BOM and schematic done, PCB layout in progress.
Features
- Fast, latching to catch quick pulses as probe is dragged along multiple pins.
- Visual/audio switchable options
- Lasts a long time on a CR2032 or similar
- Clips or magnets to a board I'm working on to save having another thing to put somewhere.
- No programmable logic, entirely simple analog/digital logic
- I almost never have projects that don't involve firmware, I'd like this to be one of them.
- Makes it easier for people to replicate without needing programming hardware/software
Rev001 Issues
- Holes for jacks are way too small (addressed in ECO A)
- Footprint for trimmers fits, but is way way oversized
- LED footprints are backwards (anode/cathode swapped, addressed in ECO B)
- Beeper/LEDs respond "analogly" due to the capacitor on the TRIGGER line
- Will add another 555 in the next revision and add a real timer for the latching functionality
- Second 555 rather than a 556 so we can have one on always for the sensing and turn the second on as-needed for the beeper, saving battery power
- Current draw idle is a bit higher than I'd like, should try to optimize this further
- Duty cycle control isn't really useful, should reevaluate need for it in Rev002
Rev001 ECOs =
- A - Trim legs on both jacks slightly to enable them to fit through the holes.
- B - Mount LEDs upside down to work around the reversed footprint.
Current Draw
- Rev001 w/ ECO A+B
- Idle - 465uA
- Beeper - 1.5mA
- LEDs - 3mA
