Ohm [fork]

Your rating: None Average: 4.7 (19 votes)

A helper tool for electronic parts.

Fork of https://github.com/thesignal/ohm



  • SMD Resitor Calculator
  • Resistor with colorrigns calculator
  • Capacitor calculator
  • Induction colorrings calculator
  • DMX-512 dip switch calculator

Equations for:

  • Ohm's Law
  • LC Resonators
  • Air-core coils

Pin assignments cheat-sheets:

  • USB
  • VGA
  • DB-9
  • DB-25
  • RJ-45
  • S-Video
  • PS/2
  • MIDI

Want more pin layouts (SCART, HDMI etc)? Submit your own additions as pull request!

Sources on github

Application versions: 
File harbour-ohm-1.2-4.armv7hl.rpm214.31 KB12/03/2018 - 00:55
File harbour-ohm-1.2-4.i486.rpm214.42 KB12/03/2018 - 00:55
File harbour-ohm-1.2-5.armv7hl.rpm214.36 KB20/03/2018 - 00:42
File harbour-ohm-1.2-5.i486.rpm214.47 KB20/03/2018 - 00:42
File harbour-ohm-1.2-6.armv7hl.rpm292.72 KB25/03/2018 - 23:42
File harbour-ohm-1.2-6.i486.rpm292.84 KB25/03/2018 - 23:42
File harbour-ohm-1.2-7.armv7hl.rpm335.68 KB14/04/2018 - 22:23
File harbour-ohm-1.2-7.i486.rpm335.79 KB14/04/2018 - 22:23
File harbour-ohm-1.2-8.i486.rpm340.48 KB15/11/2018 - 22:50
File harbour-ohm-1.2-8.armv7hl.rpm340.39 KB15/11/2018 - 22:50
File harbour-ohm-1.2-9.armv7hl.rpm354.37 KB09/02/2019 - 16:07
File harbour-ohm-1.2-9.i486.rpm354.46 KB09/02/2019 - 16:07
File harbour-ohm-1.3-1.aarch64.rpm370.25 KB07/11/2021 - 14:21
File harbour-ohm-1.3-1.i486.rpm370.15 KB07/11/2021 - 14:21
File harbour-ohm-1.3-1.armv7hl.rpm369.98 KB07/11/2021 - 14:21
  • 1.3-1 Added sailjail sandboxing rules
  • 1.2-9 fixed broken resistor/inductor colors after light theme changes
  • 1.2-8 Fixed icons to match light ambiences
  • 1.2-7 Added MIDI pin layout
  • 1.2-6 Added S-Video and PS/2 pin layout
  • 1.2-5 More emphasis on selected ring color
  • 1.2-4 Removed empty translation strings, as it made the usb page crash
  • 1.2-3
    • Added numbers to dmx-512 dip switches
    • Strings are now translatable
  • 1.2-2 Added dmx-512 dip switch calculator
  • 1.2-1
    • Scale images for multiple resolutions
    • Swapped incorrect pin 2 and 4 for serial db-9 connector
    • Replaced incorrect vga male layout
    • Added DB-25 connector (serial and parallel)
    • Added RJ-45 Ethernet connector


Malakay's picture

So, I tried to add one wiring, but I have to tell it is really complicated with editing QML and cant check what changed. I cant help myself, but this editing style really pissed me off :( We have to invent some another method. I really want to contribute with another wirings, but this is really really complicated way. Why it cant be in html or something similar to see it while creating? 

ade's picture

QML is not HTML. I like QML for frontends, but maybe you have to get used to it. If you don't want to test via the phone you could install the development SDK. It has an emulator to show you the result.

Malakay's picture

Ah, okay, I will test :) when my file is complete and working, where to put it on github? And how long will it take to appear on storeman?

ade's picture

You can fork my repo, make changes and create a pull request.

I then can create a new version, only if your addition meets a certain quality standard of course.

Malakay's picture

Now i am looking how to add more pinouts and there is one thing i cant understand - how do I check how it will look inside the app before i add it to github? Is that qml viewable for example in browser?

ade's picture

As a quick hack on the phone:

Get your own qml file on the phone, let's say /home/nemo/yourfile.qml
Become root in a terminal (devel-su for example)
cd /usr/share/harbour-ohm/qml/pages/
mv midi.qml midi.qml.old
cp /home/nemo/yourfile.qml midi.qmlfile

Now when you start the app and select midi layout, you should see your new page instead.

And restore afterwards (as root):
cd /usr/share/harbour-ohm/qml/pages/
mv midi.qml.old midi.qml

Same idea goes for related images (to be found in /usr/share/harbour-ohm/qml/img)

Malakay's picture

Oh, restart helped :)

Malakay's picture

Hi Arno, I would add some pinouts, no problem, but I installed app on Xperia X hossa, and just after install app cant start :(

Kelmi's picture

More Pinouts would be nice indeed. Wondering when we get more. Seems that thete is no work for me anymore, so just waiting?

ade's picture

A request was made to make translations possible (https://openrepos.net/comment/23826#comment-23826) and, on request, I briefly explained how to add more pin layouts (https://openrepos.net/comment/23826#comment-23826). The description asks for personal contributions to more pin layouts. But I never got a response. Apparently people have their priorities elsewhere when push comes to shove. No problem, but don't expect me to chip in as usual, I think I did my share on expanding this app.

OpenDen's picture

Будем пробовать, спасибо

OpenDen's picture

Приложение отличное и очень удобное

OpenDen's picture

Здравствуйте. Добавьте пожалуйста варианты обжима витой пары RJ-45

ade's picture

Поскольку я заявил, что не делаю запросов, попробуйте внести свой вклад.

axolotl's picture

Very useful. Is there a way to make the selection in color choosers better readable (for example a small arrow next to the chosen option)?

ade's picture

Not sure if arrows is what I would like. But I made some changes in the latest release that highlight the selected color more clear.

axolotl's picture

Great solution :) Thanks!

explit's picture

Great app, thanks! How i can help you to add more Pinouts?

ade's picture

It should not be that hard:

  • Get your clipart in a width of about 700pixels (it get's resized, so not very important)
  • Then you can take serial_pins.qml (see github) as a start for a new connector. Change the listelements (text and amount of elements) and refer to the new clipart (png)
  • The new page should also be added to the MainPage.qml, also via a new listelement
eson's picture

Your "Sources on github" is kind of fu**ed up. ;)

Anyway, thanks for the app. Will become handy.

ade's picture

Thanks, fixed the URL.

Rafaelvlmendes's picture

Hi. Thanks for this app. Can You create support to translater your app? Thank

ade's picture


I made the strings translatable. You can find the base file in the translations folder in the github repository now (harbour-ohm.ts). Qt 5 Linguist kan be used to create a translation.

silta's picture

Thanks a lot. Very useful app. I remember ElectroDroid on my Android phone ages ago ;-)

It would be great, if you could add a DMX512 calculator for dip switches similar to this on google play.


ade's picture

I think I can add this calculator. But as I wrote in the description: please create your own additions if you want them. I am not willing to spend more of my free time adding things I am not familiar with and won't use at all.

silta's picture

Oh, how fast, thank you so much. I am very happy. Can I make a donation in any way for your work?