Take the 2-minute tour ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.

Is there a way to do "jumpers" without actually using a jumper connector on a PCB, ideally just using holes or pads.

eg, one idea for doing it is to use pads on the edge of a PCB then using crocodile clips to do the bridge. Should work ok, but does require the "jumper" at the edge of the board.

These jumpers aren't meant to be a permanent part of the final board, but just to use temporarily and easily for things like diagnostics and without adding cost to the final PCB.

share|improve this question
    
Why not make a second board with the bridges and use Pogo pins? –  Ignacio Vazquez-Abrams Jun 25 at 4:54
    
yes its possible. I guess its just not super simple. You'd have to lay it out, make the board, each revision would potentially require different "jumper boards" which would get annoying if you don't have the right one readily available to you. you'd have to find a nice way to keep the pogo board clipped to the main board. –  Keith Nicholas Jun 25 at 4:58
    
the makey makey is an interesting example of mid-board crocodile clip attachment, as well as a LED mounted upside down visible through a hole. –  James Cameron Jun 25 at 4:59
    
Bitsmack's answer is bang on, although you can just put the footprint for a jumper and not fit it, then short with tweezers or a bit of wire when you need to for diagnostics. Where space is tight, SMT pads or even two small vias close together will do. –  John U Jun 25 at 8:07
    
...another alternative is to have some existing input trigger diagnostic mode. For example, I've seen a bootloader which is activated by an ADC pin being at 0v, that ADC pin measures the board voltage for the CPU, of course there is no way the CPU can be running from 0v! So, when the CPU starts and measures 0v it knows it's not real and it should go into the bootloader / test mode etc. –  John U Jun 25 at 8:10

2 Answers 2

I just saw this neat trick on a development board. You can design the PCB with pads close together, and connect your traces like so:

enter image description here

Then, melt a blob of solder onto the pads, creating a short where you want it. It can be easily changed, doesn't add to the board cost, and won't come loose :)

share|improve this answer
2  
I just put down an 0603 footprint and mark it "DNL" (for do not load). –  markt Jun 25 at 6:45
1  
@markt, Good call. I usually do what you suggest, and then solder on a zero-Ohm shunt or a piece of wire. The difference with the solution I posted is that there was only a very thin gap between the pads, and so it was easier to bridge than an actual part footprint. Take care! –  bitsmack Jun 25 at 7:02
    
I found that 0603 are way too large for this purpose. Even 0402 footprint makes it hard to solder. Custom pads are the best. –  Dzarda Jun 25 at 8:43

Easiest, use wire.

Second easiest, vias or plated holes big enough for a test clip to clip in.

Or use pogo pins on test points. The picture below shows plated holes, but some pogo pins come in pointed ends so work on smaller micro vias or simple test points.

enter image description here

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.