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2014-04-09
, 07:09
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Posts: 562 |
Thanked: 2,744 times |
Joined on Dec 2013
@ Espoo, Finland
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#2
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New TOH idea by bill_klpd, Multimeter TOH.
Seems that i started to think about this further.
First, sketching the UI:
Block diagram of the electronics part: (First draft)
First 3D sketch:
HW Specs:
Last edited by kimmoli; 2014-04-11 at 07:51.
Seems that i started to think about this further.
First, sketching the UI:
Block diagram of the electronics part: (First draft)
First 3D sketch:
HW Specs:
- Voltage measurement ranges 200mV, 2V, 20V, 200V DC (AC TBD)
- Current measurement 200mA, 2A (TBD)
- Resistance measurement 200, 2k, 200k, 20MEGohms (TBD)
- Possibility to measure low-side current and high-side voltage at the same time --> Power (W) measurement.
- Isolated from phone (floating) should be safe to keep USB charger connected while taking measurements.
- Fused current measurement
- Continuous measurements with adjustable rate
- Min/avg/max display
- Single shot measurement when in hold mode
- Beep when new min max value, or beep when short in Resistance mode.
- Logging of readings with timestamps
- Trigger events with alerts also possible TBD
- "Plotter" view on separate page of latest results TBD
- or simpler graph view in main page TBD
__________________
TOH ideas, concepts and creations since 2013 toholed tohuart toheink Heebo tohIRi i2ctool tohmm LeTOH FMTOH
TOH ideas, concepts and creations since 2013 toholed tohuart toheink Heebo tohIRi i2ctool tohmm LeTOH FMTOH
Last edited by kimmoli; 2014-04-11 at 07:51.
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2014-04-09
, 07:11
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Posts: 6,436 |
Thanked: 12,701 times |
Joined on Nov 2011
@ Ängelholm, Sweden
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#3
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future is coming!
also please add short circuit mode checking with beep signal.
also please add short circuit mode checking with beep signal.
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2014-04-09
, 07:30
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Community Council |
Posts: 4,920 |
Thanked: 12,867 times |
Joined on May 2012
@ Southerrn Finland
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#4
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Originally Posted by coderus
Hmmh, why not an oscilloscope, or at least a possibility to plot voltage changes over time...
future is coming!
also please add short circuit mode checking with beep signal.
Usually multimeter functionality is implemented by sampling the voltage in analog hold, and then measuring the time differential when bleeding it off through a known resistance. (this allows for really accurate measurement with no A/D converter needed, and is easy/cheap to implement with a dedicated chip).
However with a real fast-sampling A/D conversion it woud be possible to get the waveform plot too.
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2014-04-09
, 08:12
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Community Council |
Posts: 4,920 |
Thanked: 12,867 times |
Joined on May 2012
@ Southerrn Finland
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#6
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Originally Posted by coderus
Sorry, I meant to add a post, not reply to yours!
why not? i'm just asking what i want
Continuity beep is a good feature, yes.
However, what I'd like to have is the scope mode
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2014-04-09
, 08:12
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Posts: 562 |
Thanked: 2,744 times |
Joined on Dec 2013
@ Espoo, Finland
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#7
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Originally Posted by juiceme
See specs ^^
Hmmh, why not an oscilloscope, or at least a possibility to plot voltage changes over time...
Note; This is not a oscilloscope. That toh will be done later with its own micro to buffer/preprocess samples.
Originally Posted by juiceme
For me that is also an A/D converter
Usually multimeter functionality is implemented by sampling the voltage in analog hold, and then measuring the time differential when bleeding it off through a known resistance. (this allows for really accurate measurement with no A/D converter needed, and is easy/cheap to implement with a dedicated chip).
However with a real fast-sampling A/D conversion it woud be possible to get the waveform plot too.[/QUOTE]
Maximum samplerate with A/D converter selected (atm) is 860 sps.
400kHz I2C limits samplerate to about 7ksps, (at 16bits) but when taking IOCTL etc into account, maybe something like 10 sps in realtime could be doable without buffering...
(if taking samples in background for a short period of time, 860sps is doable)
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2014-04-09
, 08:44
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Posts: 562 |
Thanked: 2,744 times |
Joined on Dec 2013
@ Espoo, Finland
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#9
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Originally Posted by nieldk
Logic analyzer will be in tohscope
I would really like to see a logic analyzer
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| Tags |
| multimeter, other half |
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Multimeter
Icon by solbrit
TOH ideas, concepts and creations since 2013 toholed tohuart toheink Heebo tohIRi i2ctool tohmm LeTOH FMTOH
Last edited by kimmoli; 2014-04-09 at 08:45.