Electronic Project Soldering Question

[ThePringler]

Hi all,



Firstly, I know I' am new but I have been looking for a good 'hobby electronics' forum for a while now and i think Ive found one.


On to my project...

Basically I am making a alarm clock well say that is controlled by a PIC. For this project I am using many 14 segment LED displays. Each display has ~30 PINs or leeds and I will need to solder a wire to each PIN. I'm wondering if anyone has suggestions for soldering these wires.

Splicing the wires and soldering them to each Leed is quite frustrating and time consuming.

I have also tried soldering the displays to vector boards where the traces are connected together. (soldering the PIN into the vector board and soldering the wire to the connected hole beside it. However this method can get expensive.

I have also thought about using headers and connecting them directly to the displays without soldering but i am not sure if they will fit properly/secure enough.


example of LED display:


https://image.ec21.com/image/optoel...293167/Multy_Digits_7-segment_LED_Display.jpg


If anyone has done a project like this in the past or has any suggestions I would appreciate it!!!


Thanks for your time!


-Br

 

[srizbf]

using the headers may reduce your work.
find a pcb mounting header that have the required pitch suitable to your display.

 

[Nick C.]

Rolling your own headers is one possibility, but as stated by srizbf, you'll need to make sure that the pitch of the female headers matches your displays. It's still quite a bit time consuming, though, as for each connection you need to strip the wire, insert it in the female header, crimp it, then stick it in the plastic holder. Believe me, that gets old pretty fast.

**broken link removed**

Another option, assuming that you are only building one of these devices, is wire-wrapping. Kind of messy and can easily turn into a 'rats nest', though.

Even if this is a one-off, with all of those connections, I'd be tempted to go from solderless breadboard prototype straight to PCB. It might sounds like a lot of work to create/expose/etch, and it is. Still, it might be faster than running/soldering hundreds of pieces of wire.

 

[ThePringler]

Rolling your own headers is one possibility, but as stated by srizbf, you'll need to make sure that the pitch of the female headers matches your displays. It's still quite a bit time consuming, though, as for each connection you need to strip the wire, insert it in the female header, crimp it, then stick it in the plastic holder. Believe me, that gets old pretty fast.

**broken link removed**

Another option, assuming that you are only building one of these devices, is wire-wrapping. Kind of messy and can easily turn into a 'rats nest', though.

Even if this is a one-off, with all of those connections, I'd be tempted to go from solderless breadboard prototype straight to PCB. It might sounds like a lot of work to create/expose/etch, and it is. Still, it might be faster than running/soldering hundreds of pieces of wire.

Thanks for the replies!


Ya ive thought of the headers but i think in the end it will be just as time consuming and potentially expensive.

When you say wire-wrapping, do you mean just splicing + soldering a wire to each PIN? It WILL be a rats nest, believe me! But i think its really my only option.


Still open to all feedback!!

 

[Nick C.]

When you say wire-wrapping, do you mean just splicing + soldering a wire to each PIN? It WILL be a rats nest, believe me! But i think its really my only option.

Wire-wrapping is an old process that uses a small tool to wrap fine wire around each lead. One nice feature is that it's very easy to fix mistakes, since nothing is soldered.

Wire wrap - Wikipedia, the free encyclopedia

On the other hand, if you do go with soldering a wire to each pin, try to use the smallest diameter stranded hook-up wire that you can find - something like 28AWG or so will do. Strip the end, wrap the lead a few times, then solder in place. Don't forget to use the 'secret sauce' - flux. Rinse, lather, repeat. The thin, flexible wire is a lot more manageable, especially when the number of wires in your harness starts rising.

 

[ThePringler]

Thanks nick c!

I will watch your wire wrapping video, thanks. I'm glad you suggested the 28 gauge wire. I was just about to complete an order with digi key. I receive my led displays tomorrow. Maybe I'll post a pic when it's all done.



Thanks everyone!

 

[Nick C.]

If you're not in a great hurry, see if you can get the wire elsewhere. Digikey is fantastic, but for some reason they gouge you on things like wire and solder. I got sticker shock recently when looking at their wire prices. I remember ordering 28ga wire from Radio Shack's online store some years ago, custom cut to the desired length, and the price was only maybe two cents per foot. Digikey sells spools of 100 feet of 28ga stranded wire for over $16. That's insane, IMHO.

I mean, if you need it, you need it. But I'd rather buy my wire elsewhere, even if I have to go to eBay. It's just the principle of the thing. I will say though, the one nice thing about a place like Digikey is that they offer a range of colors. I find that color-coding my wiring helps me keep things easier to work with and troubleshoot (red and black for power, green for data, etc).

Some cheaper wire sources (although it seems that 28ga is getting harder to find):



814-2: JAMECO VALUEPRO: Wire & Cable

.... and of course, there's always eBay.

 

[ThePringler]

If you're not in a great hurry, see if you can get the wire elsewhere. Digikey is fantastic, but for some reason they gouge you on things like wire and solder. I got sticker shock recently when looking at their wire prices. I remember ordering 28ga wire from Radio Shack's online store some years ago, custom cut to the desired length, and the price was only maybe two cents per foot. Digikey sells spools of 100 feet of 28ga stranded wire for over $16. That's insane, IMHO.

I mean, if you need it, you need it. But I'd rather buy my wire elsewhere, even if I have to go to eBay. It's just the principle of the thing. I will say though, the one nice thing about a place like Digikey is that they offer a range of colors. I find that color-coding my wiring helps me keep things easier to work with and troubleshoot (red and black for power, green for data, etc).

Some cheaper wire sources (although it seems that 28ga is getting harder to find):



814-2: JAMECO VALUEPRO: Wire & Cable

.... and of course, there's always eBay.

Great links!


Thanks so much, really. allelectronics.com looks great. I can get 3 spools for the price of 1 from digi-key. And to think i was going to sacrifice color coding because they were so expensive.

 

[ThePringler]

Just received my LED displays. Will probably post update later..

 

[Nick C.]

I know you said there were many displays, but this is MANY displays. Holy smoke! LOL
Do keep us updated. I'm looking forward to seeing your progress and the finished project.

Nick C.

 

[ThePringler]

I know you said there were many displays, but this is MANY displays. Holy smoke! LOL
Do keep us updated. I'm looking forward to seeing your progress and the finished project.

Nick C.

Thanks Nick!

Ya i know, eh? The displays were so damn cheap, the shipping from hong kong was the only real cost so i grabbed enough for life! For any future little projects i think of.

The project im working on right now will use most of those 6 digit alpha numeric displays to create a LED text book thats 4 digits high by 18 across. I found a great way to solder these displays together and multiplexing. I will post an update once i receive my wire and other parts.