I need a trick to attach a header pin to a GPS module. - Page 1
Forum section: electronics / projects

author: t1d
author_rank: Super Contributor
timestamp: August 25, 2019, 09:04:14 pm
content: Please notice the green, double arrow, on the top right-hand corner of the GPS PCB. The parts of interest are the LED and its resistor.I would like to install header pins (signal and GND) to access the PPS (Pulse Per Second) output of the GPS. This is a common DIY method to create a frequency standard from this configurable output.There are three typical means of accessing this output:- Remove the resistor and LED and solder a fine wire to the resistor input pad.- Leave the resistor and LED in place and solder a fine wire to the input pin of the resistor.- Solder a fine wire directly to the output pin of the GPS module, Pin #3.Other Makers have had success with all three of these methods. But, they leave a couple of things to be desired… The fine wire, itself, is very fragile and it is not disconnect-able.I have several of these boards. My first attempt was to attach the header pin directly to the resistor’s input. The tiny resistor instantly heated, the solder reflowed and the resistor was swept off of the board. I attached the pin to the pad, but the repeated heating and mechanical leverage of the pin lifted the pad. I exposed some of the trace and soldered to it, but it lifted for the same reasons.I was successful with soldering the wire to the module pin. Phew!<g> I installed a SMA antenna connector on the three, elongated SMD pads, nearby, and I took ground from its GND pin. See picture.I realized from this experience that, if I was to try this again, I would need to Super-Glue the resistor in place, before I attempt to solder the wire to its pin.I also discovered that the frequency of the light is only discernible up to about 15 counts per second. That’s limits it usefulness, other than to indicate that there is output occurring. And, that the signal output strength is so weak that it really doesn’t need to be shared with the light. Therefore, I will not leave the resistor in place. I will remove it and have its pad as an available option for connecting the header pin.You need to know that there is very little open space on the board with which to work. The closeup picture belies the situation. The whole board is only the size of two postage stamps. The antenna pads, mounting screw hole, vias and traces are all very close to the resistor.I would like the header pin to be mounted horizontally to the board and exit the board to the rear. You can see that the mounting screw hole is a hindrance to this desire and must be accommodated, if this option is to be used. Accordingly, I remain agreeable to any means of attachment, horizontal, or vertical, that maintains a good electrical connection and mechanical support.I have only thought of two means of mechanical support, glues of various types and drilling a pin hole.So, I would appreciate your suggestions, cautions and options. I appreciate your help and look forward to hearing your creative ideas.

author: james_s
author_rank: Super Contributor
timestamp: August 25, 2019, 09:10:29 pm
content: This should be trivial. Just scrap away a bit of solder mask over a convenient place on the ground plane and solder one of the pins of the header to that, then use a piece of kynar wire to go from the resistor pad to the other header pin.Another option is select a connector you want to use, epoxy it to the module and then use kynar wire to connect it to the desired points.

author: t1d
author_rank: Super Contributor
timestamp: August 25, 2019, 10:43:11 pm
content: Thanks for helping me, James.Quote from: james_s on August 25, 2019, 09:10:29 pmYou sure would think so, right? But, not so much. I have a fair amount of DIY skills, tools and electronics knowledge and it is still tricky enough to ask for ideas. There's just not a lot of room to work with.Quote from: james_s on August 25, 2019, 09:10:29 pmThis has merit. I had not thought of gluing a whole connector to the PCB. The entire back of the PCB is clear, because it is a SMD board. Maybe a DuPont header socket, or a BNC connector... The BNC connector is rather big and bulky, though. Hmm... I have more of the SMA connectors... Good thinking, Lincoln. I still would like more ideas, to have some options.

author: Kasper
author_rank: Frequent Contributor
timestamp: August 26, 2019, 02:17:29 am
content: Decrease your iron heat and parts shouldn't get loose so easily, the glue holding tracks down will last longer and your soldering tip will appreciate it.I would scrape mask from gnd plane where you want the header and solder the header to it. Then solder 30 AWG wire between header and resistor or module. Then glue the header to the PCB.

author: t1d
author_rank: Super Contributor
timestamp: August 26, 2019, 03:25:16 am
content: Quote from: Kasper on August 26, 2019, 02:17:29 amHi, Kasper. Thank you for joining in.The original soldering failures were due to cascading circumstances. My heat was okay. First, the pad lifted, because it wasn't strong enough to endure having the pin attached to it. The trace lifted, because I had just been on it too much. I knew it was going to happen. You have to remember that these pads and traces are super tiny. They just can't endure very much at all.You are right about the basic soldering techniques. But, what I am after is some clever solution for accessing the signal and mechanically securing whatever connector is to be used. Your suggested procedures, particularly securing the connector to the ground plane, first, is the kind of thing I am hoping for.The truth is there are only so many ways to do this and they are all fairly straight forward. Even so, somebody may have the needed inspiration to devise the perfect solution; that's why I posted the question. You and James have thought of things that I had not, so we are making progress.Thank you for your help.

author: Ian.M
author_rank: Super Contributor
timestamp: August 26, 2019, 06:00:45 am
content: Solder connector to a small scrap of stripboard, to get enough joint area to hold it reliably, clean off *ALL* flux from both the stripboard and where you are putting it, and Epoxy it to the PCB.Its probably easiest to solder the connector to the stripboard copper side up, cropping the connector pins enough so they don't go right through the stripboard, but that will be weaker than copper side down, which is more of a PITA because you'll need to file the joints fairly flat, and jam short stubs of matchstick in the corner holes of the stripboard to support it while the epoxy sets so the solder joints dont touch the PCB. Also with the copper side down, you'll have to attach the fine wires before glueing.I'd probably use a 2 pin 0.1" pitch header for the connector to match the existing one.Tip: when you have to run fine patch wires between socketed chips or modules, have very little space for connectors and you need to be able to disconnect them easily consider using turned pin socket headers cut to the required number of ways as plugs and sockets. Solder the wires to the pins for a socket and into the sockets to make a plug. If you need to polarize them to reduce the risk of misconnection, you can add a keyway by cropping one spare pin on the plug and filing smooth, and filling the corresponding socket with solder. They can easily be superglued or epoxied to the board edge or to the top of a DIP chip at the edge. The removable half's attachment to its wires can be reinforced with hotglue.

author: kripton2035
author_rank: Super Contributor
timestamp: August 26, 2019, 06:18:46 am
content: I also think that your iron is too hot. these resistors, even small, don't go away so easily.do you have a temperature controlled iron ?anyway the trick of gluing a connector to the pcb is nice.

author: Kasper
author_rank: Frequent Contributor
timestamp: August 26, 2019, 04:44:22 pm
content: Quote from: Ian.M on August 26, 2019, 06:00:45 amI do a similar thing, specially when giving stuff to other people. For a 2 pin keyed header, I use 3 pin headers. Cut the 3rd pin off the male and glue it into the 3rd hole in the female. Can also use a paint pen to put a bright colorful stripe along 1 side of male and female.

author: KL27x
author_rank: Super Contributor
timestamp: August 26, 2019, 08:36:04 pm
content: Personally, I'm eyeing the real estate right on top of the main IC. You could affix a piece of copper clad right over the top of it.The header is another place to consider. Maybe remove the header. Take a piece that is 5 pins wide, and cut the back off the last one. Solder a wire to that cut end. Then solder the header in. It might have to stick out a little more from the board than the original one.Turned pin headers are super compact. But IME, they survive only a fairly low number of insertions. Once they wear out, some of the pins will start to make intermittent contact, making them useless. I bought a large lot of these sockets when I first starting doing electronics, and I found I would rather live without them. Well, if you need an IC socket, they are pretty good for that. Not great when used as connectors.

author: Ian.M
author_rank: Super Contributor
timestamp: August 26, 2019, 09:41:54 pm
content: Yes turned pin sockets aren't particularly durable. Some are only rated for as low as 50 insertions, so they are far from ideal in any sort of breadboarding usage, but as connectors for mod-wires in equipment that will only be removed if you need occasional access for servicing, they can be satisfactory for decades.

author: t1d
author_rank: Super Contributor
timestamp: August 26, 2019, 10:51:14 pm
content: Quote from: Ian.M on August 26, 2019, 06:00:45 amAdd some board. BrilliantQuote from: Ian.M on August 26, 2019, 06:00:45 amMake a keyway. Brilliant x2

author: t1d
author_rank: Super Contributor
timestamp: August 26, 2019, 10:58:14 pm
content: Quote from: KL27x on August 26, 2019, 08:36:04 pmAttach to the roof of the module. Brilliant.Quote from: KL27x on August 26, 2019, 08:36:04 pmAdd a pin to the header. Brilliant x2.

author: t1d
author_rank: Super Contributor
timestamp: August 26, 2019, 11:00:56 pm
content: We have excellent thinking in this community! Thank you for the help.