are jumper wires the same?

Well, I ask that after finding to my surprise that they are not. I bought these low cost M-F jumpers on eBay, and they don't seem really happy on either end. To ask a really dumb question, do I need the round ones? Or was "DuPont" the wrong thing to buy?

Edit: I guess my google photo doesn't display. I am going from small motor controller boards (M) to my breadboard (F). The controllers are the standard ones that come with inexpensive 28BYJ-48 steppers. My breadboard is of good quality.

Define not being happy.


Yes they should be the same electrically. The round ones are usually moulded and I have bought some that had glue on the pins that needs rubbing off to make good electrical contact.
The square ones are usually crimped so should not suffer that problem but maybe they are not crimped very well. Test them with a multimeter and if you get several failures then let the seller know.

to define not happy:

i was having rough movement on my steppers and thought I'd damaged a driver board, was swapping wires and motors back and forth ... and suddenly I noticed that just pressing on the side of the connector improved the signal, made things work. I'm definitely NOT getting a tight fit on the male pin on the board, this one:

Not sure about the other side as well.

thanks to all, i'll test them, make sure there is no plastic on the pins, etc,.

I've bought the inexpensive jumper wires and the electrical connections they make seem to be questionable at times.

I'm definitely NOT getting a tight fit on the male pin on the board, this one:

This one?

If you mean the "IN1", IN2", IN3", IN4", and the power connection, then the "Dupont" female connectors on the leads you showed are the correct ones, so if it is not connecting then the lead is clearly faulty.

The "J3" connector on the other hand, appears to have smaller pins and the "Dupont" female connectors may well not mate correctly.

In my experience, the male dupont jumpers are nowhere near as good as the female ones. I try to use female jumpers and male pin header as much as possible, as that combination is rock solid reliable. But the wimpy little male pins are too small (make your own jokes here) - they're both narrower and shorter than the pins on male pin header - and have more problems making reliable connections as a result.

Used breadboard that has had larger things pushed into it will often not make good contact with normal sized pins (not just dupont connectors).

The male pins on cheap (stamped) stackable pin header won't make contact with female dupont headers unless you twist the pins with pliers, like half a turn or so

I have used both Pololu and Ebay male DuPont pins.
The Pololu pins are superior, the ones I got were gold tipped plated.
Have had no problems with them.
Just make up the length you need, crimp and insert the in a plastic housing.
Stranded wires and these pins are superior to solid wire.

Just make up the length you need, crimp and insert the in a plastic housing.

How do you do the crimping process in a non-painful way? I have a crimp tool that I belive is the correct one, but it's still really unpleasant to have to carefully position the pin, stick the wire into it just right then carefully crimp it down such that the wire ends up where it's supposed to be, and properly crimped. I average 1.5-2 pins per successful crimp. Does it just always suck, or am I doing something wrong?

It's unpleasant enough that I will only do it if I absolutely can't chop up pre-made ebay jumpers to make what I need.

Yes Paul, those are the ones (IN1..IN4).

Thanks for the additional notes. It seems to be drawing now and so I'm sorting software for the time being.


Follow the attached instructions in the image.


Thanks.... That's pretty much what I'm doing, but I have an awful success rate.

The problem I have is aligning the wire perfectly when it's in the crimp tool - the job really requires three hands, because you need to hold the crimp tool in one hand, position the pin with the other, and poke the wire in with the third hand. Part of the cause of my problems is that I have to close the crimp tool enough to hold the pin in place to free up a hand to hold the wire, but this bends the tabs down a bit, and I can't see very well where the wire is inside the tool.

Is there some trick to that part that I'm missing?

You can judge the quality of hook up wires if you have a power supply with constant
current control. Set to about 100mA and measure the voltage across the lead.
Calculate the resistance at this current level - if its over an ohm the cable is
junk, avoid. (ie for 100mA expect the voltage to be less than 100mV, hopefully
more like 10mV for a short length).

Don't expect cheap hookup wiring to handle more than 100mA anyway.

Once the pin and wire is processed as shown in the top right hand part of the image.
I then grasp the wire with my left hand.
Since the retaining teeth slightly compresses the insulation the pin is held in place on the end of the wire.

I then pick up the tool in my right hand, move the wire with the pin in place, with my left, then crimp.

The big trick, you can say, is to have the insulation diameter at .06" so the teeth can grip it temporarily prior to the crimp.

Wow, I have not had this kind of problem reported with 1000's of the female-female cables plus pin strips.

See info on cable and Arduino HERE:

The male-male jumpers with thin round pins like these HERE: do not make solid contact with breadboards, in my opinion..

DISCLAIMER: Mentioned stuff from my own shop...