Couple of beginner questions

I'm trying to get into arduino doing some tutorials, but some stuff is not explained, so while working with 7-segment display, I encountered things that puzzled me a bit.

  1. 7segment have two grounds(I seem to have two kathode variant) - why? I tested and it seemed to work fine with only one connected. Yet tutorial suggested I use both
  2. Breadboard schematics provided in tutorials generally suggest some non-obvious resistor placements which overburden scheme. I went with easiest setup:
    Each arduino pin connects to it's own vertical line, when jumps over gap through resistor, then going to the place it needs to be. Why tutorials are generally suggesting strange resistor placements along the horizontal lines? Is my setup bad in some way?
  3. After finishing my prototyping I would like to make neat little device instead of breadboard monstruosity I currently have. Is there some place where I can find general tips about how to build a completed device, as opposed to prototype?
  4. I bought a set, and ran out of jump-cables instantly. I suppose I will also need some kind of soldering setup, maybe plastic cases for projects, etc. Is there a buying guide for stuff you're totally going to need, which not included in standard sets?
  5. Arduino IDE is really slick, but lack of autocompletion bugs me out. Which full fledged IDE is a good alternative?

Thank you for your time!

1 Like

Two ground (common cathodes) can be seen on some displays.
Probably to help with lowering voltage drop.
If you have succeeded with using one only, should be okay to use.

A strip board is often the next step prior to making a PCB.

See these 900+ posts for ideas in electronics construction etc.:

“ I bought a set, and ran out of jump-cables instantly. ”

You know there are the TM1637 DISPLAY.

And the MAX7219

This reduces flickering of the display.

There is no "standard" for using a breadboard. I tend to span the gap when possible because it is neater (thus easier to find mistakes).

This is what most breadboards look like electrically:

As long as you know how the breadboard is wired internally, almost any arrangement of parts will work OK.

Have you tried version 2.0 of the IDE, currently in beta testing and available for download from Announcing the Arduino IDE 2.0 (beta) | Arduino Blog

Thank you all for the answers! Very useful!

Hi, @cantcreateprofilename

Well done, you are on your way, being able to decipher the original diagram to suit your understanding and spread out of the resistors is commendable for someone beginning.

Understanding how the protoboard is layed out will help in future projects.

Tom... :smiley: :+1: :coffee: :australia:

Do you mean physical placement on the bread board, or where they are in the schematic?


physical placement mainly. In this picture it seems author wanted to use less jumper cables,
but still in other tutorials I've seen a lot of time pictures are completelly unreadable due to horizontal resistor placements.


This where the author of these Fritzy diagrams needs to provide a proper readable schematic using standard symbols and layout.

Tom.... :smiley: :+1: :coffee: :australia:

Of course it does.

The two alternate cathode connections simply provide some flexibility in PCB layout as there are five pins on each side of the display. The display itself uses an internal PCB mounting the LEDs, so there would be no point not using the tenth pin. There is no need to connect both pins unless the datasheet indicates that they connect to separate parts of the display.

Tutorials are frequently written in the form of "Look, I actually got this to work. I'm just so excited, I just have to share!" :roll_eyes:

Thanks again for your answers, it's much more clear now!

Yes that is one of the weaknesses of the solderless bread board. It looks like the maker of that one started with the display and connected resistors to it and then just wired the other ends to the Arduino outputs. Then they didn’t have the skill to make the resulting diagram easy to follow.

Thing is that the pin numbers are not important and can be juggled about to produce a diagram that is much easer to follow. The the correct numbers can be assigned in software.

That is the weakness of the Fritzing system, once a person reaches the skill level to produce good results then they also know it is a dead end with regards to conveying what the actual circuit is, especially when trying to communicate it with others.

Actually I got accused of being a misogynistic by a “semi famous maker” for suggesting that beginners would be better off if they didn’t use it. How she reached that conclusion from that fact is beyond me. I was instantly blocked so I could not discuss the matter. I think that is what is called un-platforming these days.

She must be a politician. :rofl: