A couple of months ago I created a pair of test leads that where specifically designed to be used for a breadboard. (This design was a total flop).

Over the past couple of weeks, I’ve been using feedback from my original design to create a second revision (Rev2) of the breadboard test leads.

The new design will have the following specifications:

• 24 AWG - 40 Strands - Copper wire
• Length: 1 Meter
• 0.5mm rounded tampered steel pins
• Soild-State Banana Plug Gold Plated with a low contact resistance

I attached a picture of the current design for Rev2. Since, this is my first attempt at the design, the dimensions and overall layout can still be changed.

I would appreciate some feedback on this new design. Thanks

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Welcome to AAC. My immediate reaction is about two things.

1) I am curious about the advantage of your bespoke pin over a real Amphenol ICC Mini PV male terminal?
2) I am skeptical about using a pin that is much stronger then the contacts in the breadboard, this seems to be prone to damaging the breadboard.

The silicone lead and good banana plug seem fine, but "DuPont" wires are, at best, a dicey proposition and maybe it is better to source a high quality part already manufactured.

The whole "DuPont" thing is a mess anyway. The Mini-PV males are fine for the purpose, but the females, while better, are a bit different than the generic DuPont stuff. I think it would be interesting to have jumpers made with Mini-PV or Harwin M20 connectors instead of the junky stuff currently used.

 

Welcome to AAC!

A couple of months ago I created a pair of test leads that where specifically designed to be used for a breadboard. (This design was a total flop).

Why do you think you need something specifically for connecting power to a breadboard? 1 meter sounds a bit long, gold plating seems like overkill because you're not going to be drawing a lot of current with #24 wire.

I use banana plug to alligator clips, mini-grabbers to bypass capacitor/component leads or 0.025" square male headers (with component leads in the binding posts on the supply), female 2.1x5.5mm jack to mini-grabbers, etc. The wires I use to connect power to breadboard are more likely to be a foot or less. Power leads a meter long would just be in the way.

I like flexible wire, sometimes with silicon insulation, but I find that it's rarely required.

 

Hey Ya'akov,

Thank you for your feedback

1) I am curious about the advantage of your bespoke pin over a real Amphenol ICC Mini PV male terminal?
2) I am skeptical about using a pin that is much stronger then the contacts in the breadboard, this seems to be prone to damaging the breadboard.

Regular "DuPont" pins are made of sheetmetal and are prone to bending. The custom pins i'm using are made of soild steel. They are 0.5mm in diameter; smaller than a "DuPont" pin. Since the pins are smaller, the contacts on the breadboard dont have to flex as far, putting less wear on the breadboard.

Thanks again,

 

Hey Ya'akov,

Thank you for your feedback



Regular "DuPont" pins are made of sheetmetal and are prone to bending. The custom pins i'm using are made of soild steel. They are 0.5mm in diameter; smaller than a "DuPont" pin. Since the pins are smaller, the contacts on the breadboard dont have to flex as far, putting less wear on the breadboard.

Thanks again,

It would seem to me a smaller pin would have even more trouble with the dodgy connectors in the typical breadboard when they do get spread out by the many ordinary DuPont wires they will be used with.

But I was suggesting that the strength if your alternative pin could have the unintended consequence of bending the contacts of the breadboard if the wire is pulled. My thinking is to have replaceable pins made using the higher quality Amphenol or Harwin male connectors.

Or, at least make the pin emerge at right angles to the body of the connector with a much smaller standoff so it isn't such a severe moment arm for bending. Most if not all breadboards are constructed in such a way the in line with the column allows a lot of play since there is nothing to stop it while perpendicular in line with the row is pushing against one or the other contact. In that direction it would be much easier to damage the contacts by bending if the pin is much stronger than the cheap stamped internals of the breadboard.

I am not trying to be negative. I just can't tell what the advantage of your idea is over, for example, clipping micro grabber leads onto component leads—in the circuit or saved cutoffs. I frequently make staple-like jumpers which I insert in the target for connection and an unused adjacent row, or another point in the same row, to clip to with micro grabbers.

I could see a nice ring terminal made for the purpose might be handy. It also brings to mind the idea of a right angle DuPont/Mini-PV/Harwin to test probe jacks or banana jacks as a possible implementation.

 

I suggest that rather than such a heavy connector you try and use pins made for exactly the size and shape of the opening in those plastic breadboards. Those are the hard brass 0.025 inch square pins also used for wire-wrap technology. They have an added advantage of taking solder well, which will allow a wire to be wrapped around and soldered, exiting at right angle as already mentioned. These sort of pins will work much better, be far more reliable, not damage the bread board, and cost much less.

 

Thank you for all the feedback.

The steel pins I am using are slightly smaller than an ordinary DuPont pin. A DuPont pin is approximately 0.65mm in width/length, the steel pins are 0.5mm in diameter.

Breadboards are designed to accepted wire between AWG 22 - AWG 24 or 0.644mm – 0.511mm in diameter. Any wire above AWG 22 can potentially damaging the breadboard.

I prefer to use circular pins. I you insert at a 0.65mm square pin at an angle you will stretch the breadboard contacts 0.9192mm. (potentially damaging the breadboard).

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I understand your concern about the strength of the pin bending the contacts of the breadboard. I plan to do additional testing on this and post the results in another update.

Also, I have experimented with a right-angled design. Most of the feedback I received from this design was negative. They said that the grip would block some of the other pin holes around the header.

I attached a picture of the right-angled design.

Since I am still in the designing stage, the dimensions and overall layout of the cable can still be changed.

Thank you again for your feedback.

 

Breadboards are designed to accepted wire between AWG 22 - AWG 24 or 0.644mm – 0.511mm in diameter.

I find #24 to be a little too small and wires pull out too easily. That's unfortunate because I have a lot of CAT5 cable and it was an inexpensive source of jumper wires. Now I'm reverting back to #22.

 

I find #24 to be a little too small and wires pull out too easily. That's unfortunate because I have a lot of CAT5 cable and it was an inexpensive source of jumper wires. Now I'm reverting back to #22.

Thanks dl324,

I plan to get an assortment of pin sizes between 0.65mm and 0.5mm to experiment with.

 

Also, I have experimented with a right-angled design. Most of the feedback I received from this design was negative. They said that the grip would block some of the other pin holes around the header.

I attached a picture of the right-angled design.

Since I am still in the designing stage, the dimensions and overall layout of the cable can still be changed.

Thank you again for your feedback.

View attachment 270953

The way I postured the right angle version it would include a stand-off section to hold the connector a few mmmmm above the board to cleat components and wires.

 

Lately, I’ve been designing a set of test leads with contacts specially designed for breadboard use. I attached a photo of the design for reference.

I’ve been receiving mixed messages about this project. I would like to know what you all think about the new test leads.

Should I invest the money to have these test leads manufactured or is this project dead-on-arrival? Also, what do you think about Kickstarter/Indiegogo?

Thank you for the help.

 

Gold plating is a bit soft. Given that the probe end will undergo hundreds or thousands of insertions, consider nickel plating for the tip. Nickel has a higher resistance than gold, but in this application the layer is so thin that I don't think that matters as much as durability.

I like tha high strand count and silicone insulation. Not sure if #24 wire will be durable enough.

ak

 

All my 'scope probes are shielded audio cable so that electrical hum and all kinds of other interference are not picked up by ordinary unshielded "antenna" wires.
All my prototype circuits are soldered together on stripboard with very short wiring (the parts pins are most of the wiring) so that what connects to what are easy to see (a breadboard is usually a tangle of messy wires all over the place) and hum and interference are not picked up.

 

Should I invest the money to have these test leads manufactured or is this project dead-on-arrival?

The stackable banana plug is a nice feature. I used it a lot when I was a technician, but have rarely needed it for hobby stuff. I think you're going to too much bother to design something that anyone interested in electronics as a hobby can throw together in a few minutes for less than 50 cents in parts.

Also, what do you think about Kickstarter/Indiegogo?

I don't think there's a pent-up demand for that type of product for hobbyists. Businesses will go with Pomona.