Resources for wire management?

falexandru’s picture:
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I’m surprised you didn’t find the wire nuts. That’s a very common item you’ll find in any hardware here in the US. But really I don’t think wire nuts are very useful for your project. They have their applications but in this case I think you want things that can be mounted flat to a board to make all the connections very clear instead of a jumble of wires hanging free in the air.

If you like the breadboard style of connection and want an extra bus strip then you should note that the ones on the white breadboards are removable. They’re just attached by dovetail joint sort of plastic tabs and the adhesive backing so you can just cut the backing with a knife and detach the bus from the rest of the breadboard.

Wire nuts may be excellent for kids - 8-9 years old. I teach them tail -mounting :-)). Maybe not so useful for my device, you are right.

Myself I never saw one wire nut. :-). I read they are quite common in USA.

Thank you very much for reminding me about the detachable strips! Excellent idea!

OK, I was thinking about the wire nuts being used in a project that was simply a educational display rather than something that the children will actually be working with. I agree the wire nuts could be useful in that context. I'm not sure whether they are better or worse than a breadboard for that usage. The wire nuts can be a little tricky because you need approximately the right size for the number and gauge of the wires they are used on. If the wire nut is too big then it will just fall right off. If it's too small then it either won't engage the threads or else it only grabs the portion of the wires that are sticking up farther than the others and so doesn't provide a good connection. The benefit is they are larger than the little holes on the breadboard and it's very obvious that all the wires going into the wire nut are being connected together, which is not so much the case for someone who is new to a breadboard.

Other than the springs on my RadioShack "100 in 1" kit, I did all my electrical connections by twisting wires together when I was a kid but never had the wire nuts to make the connection secure.

Hi,
If you are thinking of making a more permanent/stable version of the project you described/showed at the start of this thread, then seriously think of soldering and vero or project board, the connectors you are looking at are to big and unnecessary for your electronics project, not an electrical project.
Like these;



Tom... :slight_smile:

@pert

I dont know anything about wire nuts. Do you mean that their size is proportional to the number of wires? Looks logical, but the only reference I found was about the diameter of the wire.

At the moment I am not decided what to use and how.

At the Arduino day I will display the project and discuss with kids -that is for sure. It would be nice to have them work on few connections as well.

@TomGeorge

Your suggestion made me thinking to a second stage of the project with kids - to solder. However, children Safety is quite paranoid here, hope I can find a way. Maybe I will combine soldering and cold connection.

The firs board is very uncommon here. Does it have a particular name?

Myself, I use the Arduino as a learning tool. I found that many kids do not like at all the small parts. That includes the Arduino board itself! Not to mention the wires and connections.

You may compare with the Lego World: the Lego bricks for small children are much bigger than the Lego bricks for teenagers and adults.

But even so, apart from soldering and common breadboards (in three basic versions) there is not so many items suitable for kids.

Perf boards for soldering is an exiting subject - thank you for bringing it in!

falexandru:
There are also kids joking about "getting electrocuted". One told me that it was electrocuted by 3V piles I gave him. I said that he must throw away the smartphone, because it also runs on electric piles as well.:slight_smile: . He did not :-).

One really serious safety issue with low voltages and young children is swallowing button cells - this is
extremely dangerous and life-threatening, not just from choking hazard but the corrosion of the gut wall
by electrolysis leading to internal haemorhage. Suspected swallowing of such a battery by a small child is
a full medical emergency.

@MarkT
I agree. I only use AA (preferable) or AAA piles with kids. Never button cells.

falexandru:
I dont know anything about wire nuts. Do you mean that their size is proportional to the number of wires? Looks logical, but the only reference I found was about the diameter of the wire.

This is a cutaway diagram of a wire nut:

There is a plastic housing with a hollow conical metal insert that is threaded on the inner surface. The wire nut is used to hold the stripped ends of two or more wires in tight contact with each other. You push the bundle of wires into the open end of the wire nut and then start turning the nut. The threads will engage the wires and as the wires are threaded up into the increasingly narrow metal insert they are compressed together, which holds the contact.

The maximum diameter of the bundle of wires is limited by the A dimension in the diagram.

There is another dimension not labeled in the diagram, which we shall call F. At least on some wire nuts, the metal insert does not taper all the way to a point. The inner diameter of the metal insert at the smallest point determines the minimum diameter of the bundle of wires.

The effective capacity of the wire nut is some subset of the range between A and F. You wouldn't want to use it with a bundle of diameter A or F since at A it will be very difficult to get the threads to engage the full bundle of wires and at F the nut will not exert sufficient pressure on the wire bundle to make a good connection and prevent them from being pulled out of the nut. Instead you would want to move up or down to the next size of wire nut that has a more suitable capacity range.

The diameter of the wire bundle will be determined as much by how many wires are in the bundle as by the gauge of those wires.

For safety/reliability critical applications such as mains wiring there are specific guidelines you need to follow for how many wires can be bundled in one wire nut. For temporary low voltage, low current purposes it's more a matter of what is easy to do and reasonably stable, which you will be able to quickly determine as you use them.

Thank you, @pert! Very clear.

I'm glad if it's helpful. I'm interested to hear what your findings are regarding the use of wire nuts for teaching young children about circuits. I don't think I've ever heard of someone using that approach before. I like that it's using common standard parts that have a low price rather than some outrageously expensive lego brick sort of thing.

I've heard of teachers using that adhesive copper tape to let their students make circuits but it's really hard to make connections with that stuff without soldering so I think it's a bad idea.

As soon I will put my hands on the wire nuts and use them with kids, I ll let you know. If I will not be able to procure them, I am thinking about making them.

The construction bricks adapted for electronics and "robotics" are extremely expensive, indeed.

The next stage of my prototype: mounted on the portable skeleton. See photo.

The approach to wire management was to group the components on separate mini breadboards (as shown in the previous table-mounted circuit), according to their function, in three sectors, in my case:
a) Power Sector - objects: source 3.7 LiIon 18650; DC-DC (3.7 tp 5V)
b) Processing Sector - objects : Arduino nano; LCD 1602 I2C
c) Sensors Sector - objects : logical level translator, DHT22; BMP280
Components are defined as objects and their terminals are marked to the local line (within its sector) each one use.

Each sector has its own local lines:
Power lines:

  1. GND
  2. 3.3 V (if needed)
  3. 5 V
    Data lines:
  4. I2C (2wires)
  5. Digital
    More Digital and Analog local lines can be added.

Each local line is connected to the others in the rest of the sectors.

In this way each sector can be reviewed and checked separately. There is no need for complex diagrams because each sector can only comprise few components.

I found this way as being rewarding in its simplicity.

The diagram drawn according to this concept (which I will post shortly) depicts only local lines and terminals notation.

The only problem is that this structured way of wiring needs more jumpers than the usual one.

If the circuit has to be enhanced this can be done either:
a) by adding more sectors - to the point the Board capacity is reached
b) by adding more processing units in a slave-master configuration

When translating to the perf (which I will do it) then multiple small plates is more configurable than only one big.

There are still improvements to be done, like using straight wires instead of jumpers, develop an intermediary Bread board that phisically separates sectors.

I am late in my project because the supplier changed the LCDs I used so I have to re-code.

**Question is: is somebody aware about alternative ways to draw the circuits apart form the well-known international symbol one? **

20180501_175055[1].jpg

And here you have the structured block diagram.

It is very simple: each sector has its own internal physical lines - as described in the previous post.

From one sector to another, only one wire can pass for each individual internal line. In other words, if there is only one digital wire from the sensor, it cant pass directly to the sector 1 - it shall join the internal data line first. Then, from internal data line one wire pass to sector 1.

At a first sight it looks like excessive use of wires. But the advantages are great when the circuit is tested and when it is extended - either by more objects in one sector or by more sectors.

It is also very clear whether all components share the same ground and are connected correctly to their power or data line.

Structured Block diagram A nano sensors portable device.pdf (829 KB)

I was unable to find here wire-nuts. I can either find an European provider (which is somehow excessive for a 2 dollar purchase) or attempt manufacturing (DiY) them - somehow- any suggestion welcomed!

Why not just order them online? If you would have done so when the topic first came up they would have already been delivered, even from China.

For other suggestions, it might be helpful if you said where you're located.

In my view it is a waste of money to order a 2 USD merchandise that is going to cost 50 USD delivery (or even 20 USD).

Another point is that I may need different types in different quantities, which may result in repeated orders, adding up delivery costs and waiting times.

Here in the US I can buy bags of wire nuts on eBay or Aliexpress for as little as $0.50 for 10 pcs and have them shipped to me for free from China. You can buy collections of assorted sizes or just a specific size. Is the shipping really so expensive where you're at?

falexandru:
I was unable to find here wire-nuts. I can either find an European provider (which is somehow excessive for a 2 dollar purchase) or attempt manufacturing (DiY) them - somehow- any suggestion welcomed!

wire-nuts are for electrical work not for electronics

@ Ted I know. But I want to use them for kids. I leave the wires "on air" like in the old times. Currently, I just teach kids to twist the wires by hand. To many times this operation fails because of wires sliding.

Those wire-nuts would be excellent to replace the twisting. But I want to check this before buying in bigger volumes.

For kids I want big things :-)).

I also invented a sort of tool that twist thin wires around the components terminal. But this is to small for kids :-(.

Thanks for photo!