# What's the best way to connect external wires to these PCB boards?

#### Ed. M.

Joined Nov 8, 2017
41
I purchased these boards to work with my Arduino: https://www.amazon.com/ELEGOO-Prototype-Soldering-Compatible-Arduino/dp/B072Z7Y19F/ref=sr_1_1_sspa

What's the correct way to use the boards once I solder on my ICs and connect them up? I need to attach a whole bunch of wires (20+) that will connect to my Arduino. In the past I just tried soldering the wires wherever it made sense, but that didn't work so well.

Do the tabs across the top do anything?

Are there "edge connectors" I can buy whose prongs are 0.1" apart and come in different sizes (e.g., 1x10 or 2x10)?

- Ed.

#### paulktreg

Joined Jun 2, 2008
784
Use something like these?

Solder them in and connect your wires to them.

The double sided PC01456 shown further down the page may work better.

#### dl324

Joined Mar 30, 2015
10,943
I've used EDAC card edge connectors. For those boards, you'd need to cut the corners off. Or you could use a connector with more contacts and line them up.

Personally, I'd solder 0.025" square male or female headers and use jumpers to connect to Arduino.

EDIT: card edge connectors are spendy:
https://www.digikey.com/products/en/connectors-interconnects/card-edge-connectors-edgeboard-connectors/303?k=card+edge&k=&pkeyword=card+edge&sv=0&pv89=9726&sf=1&FV=-1|151,-1|8015,-1|937,-8|303&quantity=&ColumnSort=0&page=1&pageSize=25

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#### jpanhalt

Joined Jan 18, 2008
9,699
I really do not like those hole-per-contact bread boards. I think they date back to an era (Vector boards) when one added pins as tie points (as mentioned above). I have several that lay unused.

I prefer by far protoboards that have several holes connected. In the last several years, some vendors have marketed solderable protoboards that mimic the conventional non-solderable ones. There has also emerged several vendors of variations on that design.

I have been using these for a year or so: https://www.ebay.com/itm/SB4-Two-Pack-Snappable-PC-BreadBoard-Scored-PCB-Snaps-Into-Small-Boards-2-5/254323570977?hash=item3b36ddb921:g:V98AAOSwN7BdSus~

They are easily soldered (flux coated?), have through-plated holes, and are cheaper than SparkFun's versions. I also use SF versions, but cut them up to meet my needs. I cut them roughly to a convenient size with a vinyl flooring tile cutter, then mechanically sand them to the exact size I need. The latter step is needed only when cosmetic appearance matters. The tile cutter can keep pretty accurate dimensions.

The cutter I use looks like this: https://www.homedepot.com/p/Roberts-12-in-Quick-Cut-Vinyl-Tile-VCT-Cutter-30002/100038849?MERCH=REC-_-PLP_Browse-_-203409263;100506918;301960099;310384893;301960098;305903935;-_-100038849-_-N

It was less than half that price. Shop around.

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#### TeeKay6

Joined Apr 20, 2019
572
I really do not like those hole-per-contact bread boards. I think they date back to an era (Vector boards) when one added pins as tie points (as mentioned above). I have several that lay unused.

I prefer by far protoboards that have several holes connected. In the last several years, some vendors have marketed solderable protoboards that mimic the conventional non-solderable ones. There has also emerged several vendors of variations on that design.

I have been using these for a year or so: https://www.ebay.com/itm/SB4-Two-Pack-Snappable-PC-BreadBoard-Scored-PCB-Snaps-Into-Small-Boards-2-5/254323570977?hash=item3b36ddb921:g:V98AAOSwN7BdSus~

They are easily soldered (flux coated?), have through-plated holes, and are cheaper than SparkFun's versions. I also use SF versions, but cut them up to meet my needs. I cut them roughly to a convenient size with a vinyl flooring tile cutter, then mechanically sand them to the exact size I need. The latter step is needed only when cosmetic appearance matters. The tile cutter can keep pretty accurate dimensions.

The cutter I use looks like this: https://www.homedepot.com/p/Roberts-12-in-Quick-Cut-Vinyl-Tile-VCT-Cutter-30002/100038849?MERCH=REC-_-PLP_Browse-_-203409263;100506918;301960099;310384893;301960098;305903935;-_-100038849-_-N

It was less than half that price. Shop around.
I purchased these boards to work with my Arduino: https://www.amazon.com/ELEGOO-Prototype-Soldering-Compatible-Arduino/dp/B072Z7Y19F/ref=sr_1_1_sspa
View attachment 194201

What's the correct way to use the boards once I solder on my ICs and connect them up? I need to attach a whole bunch of wires (20+) that will connect to my Arduino. In the past I just tried soldering the wires wherever it made sense, but that didn't work so well.

Do the tabs across the top do anything?

Are there "edge connectors" I can buy whose prongs are 0.1" apart and come in different sizes (e.g., 1x10 or 2x10)?

- Ed.
@Ed. M.
In your post#1, according to the image you posted, the elongated pads along the edge are not at the same spacing as the holes. If the holes are spaced 0.1" apart, then the elongated pads appear to me to be 2.5mm apart, not the 2.54mm expected for 0.1" spacing. If your posted image is to scale, then verify the spacing of the edge pads before you buy 0.1"-centers edge connectors.

#### Ed. M.

Joined Nov 8, 2017
41
@Ed. M.
In your post#1, according to the image you posted, the elongated pads along the edge are not at the same spacing as the holes. If the holes are spaced 0.1" apart, then the elongated pads appear to me to be 2.5mm apart, not the 2.54mm expected for 0.1" spacing. If your posted image is to scale, then verify the spacing of the edge pads before you buy 0.1"-centers edge connectors.
Good point. So what's the purpose of the edge pads? Decoration?

#### dl324

Joined Mar 30, 2015
10,943
Good point.
I checked some boards I have that are similar to the one you showed. The space between the edge fingers were 0.1". I fitted them into the card edge connector I showed and the fingers lined up. The problem is that the fingers are shorter than what is normally used on boards and the fingers and the first row of holes are in the connector.
So what's the purpose of the edge pads?
They could have expected you to connect wires to the pads (for a convenience and a neater appearance) and route to appropriate points on the board.
Decoration?
I think it's safe to say that they wouldn't waste space for decorations.

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#### jpanhalt

Joined Jan 18, 2008
9,699
They do not show the backside of the board, assuming there is one. On some of the Velleman boards I have, similar pads are connected with a fine trace to the last row of PTH's. That way, you have a connection to the pad without having to put solder it.

#### dl324

Joined Mar 30, 2015
10,943
Picture of the fingers lined up with card edge connector:

Picture of the fingers inserted in the connector:

#### jpanhalt

Joined Jan 18, 2008
9,699
OK, they are for those who can't think ahead. Decorative for everyone else. As I said above, I have some of those boards and have never used them.

The fact that you can solder to a hole is meaningless and just like the very old "Vector" boards where you inserted a tie post in those holes drilled in a substrate without any PTH that needed a connection. Is that old stock from the 1970's?

#### bassbindevil

Joined Jan 23, 2014
94
I vote for headers, and if possible use connector housings that hold a bunch of contacts inline, so you can unplug without worrying about wires getting mixed up. For high(ish) current stuff, barrier terminal strips and wires with fork terminals.

#### dl324

Joined Mar 30, 2015
10,943
Regarding properly sized holes vs interference fits.

I just repaired a DVR that had 3 puffy caps in the power supply section. The holes for the caps were larger than necessary (larger than 0.035" which was the largest drill bit I had handy, looked like they could have been 0.04"), lead diameter is 0.02". When I removed the solder from the last lead on each cap, they literally fell off of the board because there was so much clearance between the leads and the pads.

That was one of the easiest repairs I've done. (Okay, disassembly was a bit of a pain because there were half a dozen cables that I didn't want to remove because they didn't seem very sturdy to me. I only disconnected the cable between the power and main boards.

#### Ed. M.

Joined Nov 8, 2017
41
I vote for headers, and if possible use connector housings that hold a bunch of contacts inline, so you can unplug without worrying about wires getting mixed up. For high(ish) current stuff, barrier terminal strips and wires with fork terminals.
I'm attaching a pin header, 2x15 to my board. Can I buy wires with female connectors on both ends with various housings somewhere? I looked on Amazon and all I see are 8" F/F wires which are much too long (I need 3-4"). I have a crimping tool, but those Dupont connectors look awfully small.

#### dl324

Joined Mar 30, 2015
10,943
Can I buy wires with female connectors on both ends with various housings somewhere?
This is one thing that I'll buy from Ali Express.

I looked on Amazon and all I see are 8" F/F wires which are much too long (I need 3-4").
You can buy 10cm long jumpers on Ali Express.
https://www.aliexpress.com/item/32782378444.html?spm=a2g0o.productlist.0.0.192658793tVAr8&s=p&algo_pvid=a6b976c0-1eb0-4c1e-90f5-1082343e9ff7&algo_expid=a6b976c0-1eb0-4c1e-90f5-1082343e9ff7-1&btsid=4ef0960d-b5fd-4c2e-8a59-41acdd3600ef&ws_ab_test=searchweb0_0,searchweb201602_7,searchweb201603_53
Look around for a better price. I've been buying the 20cm junpers for under $1 for 20. Better price,$0.63 for 40 wires with free shipping:
https://www.aliexpress.com/item/32891879068.html?spm=a2g0o.productlist.0.0.192658793tVAr8&algo_pvid=a6b976c0-1eb0-4c1e-90f5-1082343e9ff7&algo_expid=a6b976c0-1eb0-4c1e-90f5-1082343e9ff7-11&btsid=4ef0960d-b5fd-4c2e-8a59-41acdd3600ef&ws_ab_test=searchweb0_0,searchweb201602_7,searchweb201603_53

I have a crimping tool, but those Dupont connectors look awfully small.
They're not that difficult. A ratcheting crimper helps. They're cheap on Ali Express (another thing I'll buy from them).

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#### bassbindevil

Joined Jan 23, 2014
94
So, which of the cheap crimpers are worth getting? I've heard good things about the Engineer PA-09 crimpers, but they are double to triple the price of the no-name SN01BM and SN-28B ratchet crimpers.

#### dl324

Joined Mar 30, 2015
10,943
So, which of the cheap crimpers are worth getting? I've heard good things about the Engineer PA-09 crimpers, but they are double to triple the price of the no-name SN01BM and SN-28B ratchet crimpers.
I have SN-28B. Unless you need something custom, you can't beat the price and convenience of the ready made jumpers.

#### KeepItSimpleStupid

Joined Mar 4, 2014
4,102
They could have expected you to connect wires to the pads (for a convenience and a neater appearance) and route to appropriate points on the board.
It's a lot easier and neater to do cross-connects. When I made some wall mounted control panels using DIN rail, basicall "decided" since I had no training to put a row of screw terminals where the conduits enter. You really don't want to chase down wires going to some relay in the middle of the enclosure.

I took the model from the phone company telephone closets at work. It's cables between closets and cross-connects within the closets.

I set up some ersatz automation systems using Labview and NuBus cards (against my judgement). I was "forced" to do it this way. Sometimes you have a connector to an instrument with analog I/O and digital I/O and cards that are analog input, analog output and digital I/O. You can bring that instrument connector into a third place which takes that cable to screw terminals and then connect to the various cards.

--

#### ErnieM

Joined Apr 24, 2011
8,046
I very much like that style of breadboard. IMHO humans need 0.1" spacing to work usefully, and these supply that in droves. I keep these boards in my stock from the smallest to the largest, which is 15x20 cm. Here is one project I bread boarded using them:

As you see I use converters to wiggle very tight surface mount parts back into workable 0.1" spacing.

Wire is 30 AWG (or so) that I use an old wire wrap tool to strip, plus some solid bus wire for power. 0805 size surface mount parts work very well going between two pads so that is what I use. Leaded components are not desired.

However, I never found anything to work with the "connector pins" either. Even if one did, there is no clean way to connect to them. I just ignore them.

There are some connectors used here, here's some EBay links to similar things: