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-   -   tohmm TOH Multimeter (https://talk.maemo.org/showthread.php?t=92994)

kimmoli 2014-04-09 07:04

tohmm TOH Multimeter
 
https://pbs.twimg.com/media/BkusonRCAAA4BcG.png
Multimeter

Icon by solbrit

kimmoli 2014-04-09 07:09

Re: tohmm TOH Multimeter
 
New TOH idea by bill_klpd, Multimeter TOH.

Seems that i started to think about this further.

First, sketching the UI:
https://lh6.googleusercontent.com/-0...0409100124.jpg

Block diagram of the electronics part: (First draft)
https://lh5.googleusercontent.com/-v...o/tohmm100.png

First 3D sketch:
https://lh4.googleusercontent.com/-L...m-mockup-1.png

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
SW Specs:
  • 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

coderus 2014-04-09 07:11

Re: tohmm TOH Multimeter
 
future is coming!

also please add short circuit mode checking with beep signal.

juiceme 2014-04-09 07:30

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by coderus (Post 1420476)
future is coming!

also please add short circuit mode checking with beep signal.

Hmmh, why not an oscilloscope, or at least a possibility to plot voltage changes over time... :D

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.

coderus 2014-04-09 07:54

Re: tohmm TOH Multimeter
 
why not? i'm just asking what i want :)

juiceme 2014-04-09 08:12

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by coderus (Post 1420478)
why not? i'm just asking what i want :)

Sorry, I meant to add a post, not reply to yours!
Continuity beep is a good feature, yes.

However, what I'd like to have is the scope mode :)

kimmoli 2014-04-09 08:12

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by juiceme (Post 1420477)
Hmmh, why not an oscilloscope, or at least a possibility to plot voltage changes over time... :D

See specs ^^
Note; This is not a oscilloscope. That toh will be done later with its own micro to buffer/preprocess samples.

Quote:

Originally Posted by juiceme (Post 1420477)
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).

For me that is also an A/D converter :rolleyes:

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)

nieldk 2014-04-09 08:23

Re: tohmm TOH Multimeter
 
I would really like to see a logic analyzer :)

kimmoli 2014-04-09 08:44

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by nieldk (Post 1420484)
I would really like to see a logic analyzer :)

Logic analyzer will be in tohscope

bill_klpd 2014-04-09 08:58

Re: tohmm TOH Multimeter
 
Great work kimmoli! Keep up :D

nieldk 2014-04-09 09:23

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by kimmoli (Post 1420487)
Logic analyzer will be in tohscope

Then,

'should the f... up and take my money' :)

Please add me to be #1 :)

pichlo 2014-04-09 11:57

Re: tohmm TOH Multimeter
 
OMG! A multimeter, an oscilloscope... Will you please stop any time soon? You are making it harder and harder every day to keep resisting buying a Jolla! :)

nokiabot 2014-04-09 13:15

Re: tohmm TOH Multimeter
 
omg ! i think you have gone mad or possibly a toh fever :D

vincr 2014-04-09 13:29

Wow! Great work! Would like to have a Jolla right now!

kimmoli 2014-04-09 13:30

Re: tohmm TOH Multimeter
 
No rush for this...
it will take some time before HW realized...

vincr 2014-04-09 14:43

I would add the jolla to my multimeter collection then :p

Sailfex 2014-04-09 14:53

Re: tohmm TOH Multimeter
 
This is too good to be true !!

Count me in :)

junnuvi 2014-04-09 15:03

Re: tohmm TOH Multimeter
 
This is something which I have been wondering since I heard about jolla TOH. Count me in too!

solbrit 2014-04-09 16:12

Re: tohmm TOH Multimeter
 
I thought you were just working on an app but it's a new Kimmoli brand TOH. And a very interesting and ambitious one at that... I'm definitely in!

xman 2014-04-11 05:58

Re: tohmm TOH Multimeter
 
This is great idea for TOH, however the image of scared me. Where doesn fused go? We don't want any ppl to burn there devies.

kimmoli 2014-04-11 07:52

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by xman (Post 1420801)
Where doesn fused go?

Thanks for reminder... Added fused current measurement to specifications.

shadowjk 2014-04-13 07:49

Re: tohmm TOH Multimeter
 
Where do I preorder? :)

seiichiro0185 2014-04-13 08:05

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by shadowjk (Post 1421190)
Where do I preorder? :)

+1

I really like this idea :)

Kabouik 2014-04-14 00:53

Re: tohmm TOH Multimeter
 
I'm in too. I kind of plan on collecting all Kimmoli's OH, I guess.

tvicol 2014-04-25 07:34

Re: tohmm TOH Multimeter
 
I'm in too.

nieldk 2014-07-09 20:40

Re: tohmm TOH Multimeter
 
just a bumb ;)

kimmoli 2014-07-14 15:36

Re: tohmm TOH Multimeter
 
More detailed 3d. Trying to print this out prop tomorrow...

https://lh3.googleusercontent.com/-C.../tohmm-1-8.jpg

pichlo 2014-09-25 06:25

Re: tohmm TOH Multimeter
 
What's the current status of this?

kimmoli 2014-09-25 07:40

Re: tohmm TOH Multimeter
 
Quote:

Originally Posted by pichlo (Post 1440454)
What's the current status of this?

No progress... been too busy

cvp 2014-09-25 10:03

Re: tohmm TOH Multimeter
 
its very interessting, think i want one, if the progree will be finished :)

philter 2015-07-07 11:26

Re: tohmm TOH Multimeter
 
Hi there! I was wondering how to develop a TOH oscilloscope: I have this max128B circuit already, and was thinking to use in place of ads1112-1, 6101fh, PCF8591 ADCs used by Kimmoli.
I'll start from this project and add my updates.
Actually the library is this one:
http://vesta.homelinux.free.fr/wiki/...circuit_Max128

Soon I will update the schematics.
Bye


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