Some really basic questions on circuit boards

I am completely new to circuit boards, Arduino etc, and can’t figure out a few basic things.

  1. Why is the CPU always in the middle of the breadboard. Can you put it in the corner? Because if I wanted to build a really small breadboard device, having to put the CPU in the middle of 2 connected breadboards with long wires connecting everything, would be a huge waste of real estate space.

  2. Is it possible to build a simple vibrator device, using nothing other than a battery, a sensor-based switch, and then a vibrator, simply connected together with wires, and no breadboard or CPU? Can I just simply wire or solder these components together and then the vibrator will only vibrate when, say, there is a certain amount of light picked up by the light sensor switch in between the battery and vibrator? And the entire thing keeps running indefinitely until the battery runs out of juice?

  3. What is the difference between these sticky-out style GPIO pins seen on a Arduino Nano or Raspberry Pi 3, and between the hole pins seen on a LilyPad e-textiles device? In other words, can you connect any sensor, haptic vibrator etc, to either a sticky-out GPIO pin, or a hole-style LilyPad connector, or solder it? Or are some devices specifically for one type of PIN or the other? So let’s say I wanted to build the same thing as I said above, with the battery, the light-based switch and the vibrator. Could I plug that into either a sticky-out style GPIO, or a breadboard style hole, or sew it into a LilyPad style hole, and it all work the same in all of these cases, so long as the amps and voltage were the right numbers?

  4. What happens if salt gets into a circuit board, breadboard, connecting wire etc? Would this short circuit or otherwise stop the thing from working? If so, is there any way to coat the components to stop any damage from salt?

Basically I am trying to build something really compact and all of these boards seem too big.


I assume that you mean circuit board rather than breadboard. It is there because it makes routing traces to pins along the edge of the board easier. You can place the chip anywhere on the PCB that suits you


The pins take jumper wires with sockets on them
The sockets take jumper wires with pins on them
If you are going to make a permanent device then use solder pads rather than pins/sockets and jumper wires

Thanks for the reply. How about my question on whether you can use these devices on any given connection? Would a haptic vibrator or switch or battery work on either a sticky-out GPIO or a threaded sewn LilyPad device, or not?

Yes, as long as the pin can deliver the correct voltage and current

It's bad news for your electronics. They will malfunction, either eight away, or over time. They either go dead on you, or start exhibiting erratic behavior.

Are designed to have conductive thread tied and knotted to them, or perhaps jumper clips...

Mostly jumper clips in the case of the micro:bit.

Somehow, I could not be terribly confident about the reliability of conductive thread. :worried:

What do you think about the reliability of conductive ink? Any good?

Hi, @kingneil
Welcome to the forum.

Can you please tell us your electronics, programming, arduino, hardware experience?

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

I have been reading a bit about electronics and science-type stuff for the last few weeks, and I did some computer programming in my teenage years.

What this thread is about, is that I need a really small device, and the smallest boards I could find, were Arduino Nano Every, and Pico, and I'm pretty sure these won't be small enough.

So then, I looked at breadboards, and was confused by people putting the CPU right in the middle of 2 breadboards, because that's going to take up too much space once again.

Then I looked at whether you can cut up breadboards, and some say yes, and some say no.

Then I looked at whether you can avoid breadboards altogether, and just hook up each component with wires, and someone in this thread said yes.

Then I found something called conductive ink, and I asked in this thread whether this has worked well for anyone, and no one has yet replied. Amazon reviews are mixed.

So far, I haven't found super-small breadboards, if they exist. But I may well come across them, or perhaps someone could point me in the right direction.

I also saw a YouTube video where someone printed a tiny circuit board onto paper, which may be what I need, but I'm seeing if I can do this without buying an expensive printer.

That is basically the summary of everything.

If it needs to be really small, forget breadboards etc. You'll have to get a custom pcb and someone to make it for you. I do this myself at home for my stuff, but it's a very steep learning curve.

@kingneil please post a picture of what you are calling a breadboard. From your comments it may not be the same thing as I think of as a breadboard


That has confirmed that we mean the same thing when referring to a breadboard, but it leaves confused

If you want to build your project as small as possible then why are you even considering using a breadboard when a printed circuit board or a piece of perf board would be so much smaller ?

A perfboard seems like it might be the right thing.

On a perfboard does it matter which order I arrange the components in, like, clockwise, counterclockwise, or does it not matter so long as all the components support the voltage, amps etc?

With board layout, you're juggling several requirements, but if you start out, the most important thing you'll want to keep an eye on is that everything connects to each other the way it should. Try assembling a simple circuit on perfboard; you'll quickly see that it matters a lot how you position the components in relation to each other if you want the wiring to be as straightforward as possible.

There's a lot more to be said about it, but I'd recommend to just give it a go and learn as you go.

While the Nano is the smallest Official Arduino board, there are third-party boards that are much smaller.

There are also some older ATtiny85 boards (digispark is best known) that use a software USB implementation for booting that seems to be rapidly losing compatibility with newer PCs, but they should also work with an external programmer.

What are you trying to do? If you tell us we could help you with it.

Hi, @kingneil

Before we go any further, can you please tell us what your proposed project is?
What environment it is supposed to work in?

If we know that, then we can answer your questions about connections and components with more accuracy.

We have used 18 posts and really have no idea what you are aiming at.

At the moment you could be building a flashing LED circuit or the AI unit in a Tesla Sports!

Please read the post at the start of any forum , entitled "How to use this Forum".

The usual process to develop a project is to breadboard it first, forget about making it small.
Just get the device working.
When you have a working prototype, then you can work towards miniaturization.
Those of us that have gone down the prototype road, it is sometimes long and sometimes means changing an approach as the project develops.
Nothing works first time if you are designing from scratch.

Thanks.. Tom... :smiley: :+1: :australia:

To give an illustration, on a particular module I've been working on and off for months, and it has gone (so far) trhough about 3 fundamentally different breadboard versions, about 5 diy PCB's and the end is not yet in sight! Well, that's an extreme example from my end where I bit off more than I can chew, but I guess we all run into that from time to time.

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