Breaking out 1.27mm single row header pins, at least nine - Page 1
Forum section: electronics / beginners

author: GarthyD
author_rank: Regular Contributor
timestamp: September 05, 2023, 11:04:31 pm
content: I have purchased the accursed BMI270 Shuttle Board 3.0 and it turns out that the physical interface to it is a single row of 7-pin 1.27mm-spaced male headers, and a separate row of 9-pin 7-pin 1.27mm-spaced male headers.I'd like to work with 2.54mm jumper wire instead and want to adapt it.I would have assumed that I could just pick up a cable that adapts from single row 1.27mm to 2.54mm, but apparently it isn't that easy.I definitely don't want to build my own cable. I'd prefer to limit any soldering to breakout boards. I do not want to solder to the board itself.I've found some 1.27mm-2.54mm adapter board, but those aren't as readily available without waiting a long time for international delivery, and assuming I can find some female headers I could use that.Searching for options has been quite difficult, especially as 1.27mm seems to be a common wire pitch and SMD pin distance, so I get a lot of very wrong things show up when I search.It's an IMU/accelerometer so I want to move it around a bit, so temporary delicate connections won't work.I'm tempted to just cut my losses and get a suitable breakout (say a Sparkfun BMI270 breakout) and just use the BMI270 Shuttle Board 3.0 as a paperweight.Before I take that option though, can anyone recommend the easiest possible way to do this?

author: themadhippy
author_rank: Super Contributor
timestamp: September 05, 2023, 11:13:33 pm
content: buy a female-female cable with 1.27 sockets ,cut it in half and solder the wire ends to a bit of vero board along with 2.54mm headers

author: GarthyD
author_rank: Regular Contributor
timestamp: September 06, 2023, 03:27:51 am
content: Thankyou, I'll think about that. I'm looking for something in line with my original question. Let's see what other options come up, there have to be a few ways to approach this.

author: YTusername
author_rank: Regular Contributor
timestamp: September 06, 2023, 08:53:28 am
content: I have the BMI270 Shuttle Board 3.0 too. I don't know why they took the decision to use such a 1.27 header. The BMI270 Shuttle Board 2.0 was the breadboard friendly. The only difference is the Mag which is older with one generation but identical (BMM150 and BMM350).You can make robust breakout using two 1.27 female headers as I did. I used hot glue to fix the header very well and soldered isolated wires (transformer core wires) to jumper the 1.27 with 2.54 headers.

author: GarthyD
author_rank: Regular Contributor
timestamp: September 06, 2023, 11:47:42 am
content: Ah, it's interesting to see the approach. It makes wish I'd caught the rev 2. Thankyou, I'll have to weigh up the approach, I'm missing most of what I'd need for this and it's a lot to get one part going.I'm leaning to dropping it for now. No point throwing good time after bad money if their solution is too painful to use. Their fault for the bad design, mine for not checking more closely before buying. Still, I hope someone has seen something that could make this easier.EDIT: If I do put things off, I'll likely start gathering bits and pieces over time and have a crack at one of the solutions here when I'm doing some other solder/assembly work.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 07, 2023, 02:06:08 pm
content: Using lacquered "enameled" wire is a relatively easy and quick way for prototyping because you do not need to strip it, but can burn off the insulation during soldering. For a thing like this I would probably have soldered an IDC connector to a small piece of perf board and glued that to your breakout board, and then solder lacqurered 0.2mm wires directly between the two headers. It does look "ugly", but it is actually quite reliable. But although lacquered wire is easy to work with, making such a thing easily takes up half an hour of your time.When working with lacquered wire, you ideally have two soldering irons. One is set a bit hotter then usual and you use it to burn off the insulation and pre-tin the wire, and you use the other at a lower temperature for soldering the wire to the PCB. Doing this with a separate iron both reduces the chance of damage to the PCB (pads get off easily when very hot) and it also reduces the chance of burning though the insulation in spots you do not want to damage the isolated wires.You can of course also do this by constantly adjusting the temperature of a single iron, but you will get annoyed by that quickly.

author: GarthyD
author_rank: Regular Contributor
timestamp: September 10, 2023, 10:11:13 am
content: Thankyou for your thoughts on this one, I'll will keep that in mind.It seems there's no quick fix like I was hoping for. I've kicked the problem down the road a bit by just ordering a different breakout with sensible headers. In this case the alternate breakout will see me through until I've got the time to look into other possible solutions. Whilst I was hoping there'd be an easier solution, I appreciate you all taking the time to offer some possible solutions. Many thanks.