Using all Teensy3.x pins with a socket.

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jimmayhugh

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I like to use a socket on my Teensy3.x projects to allow me to re-use the Teensy3.x device.

Lately there has been a lot of discussion concerning the fragility of the extra pin pads on the underside of the board, and how they don't hold up well to repeated insertions and extractions. It seemed to me that there was a need for a little more structural rigidity. To that end, here's my solution:

I got some snappable dual row .1"x.1" headers, like you might find at Adafruit, ebay, etc. I also got some right-angle headers.

After breaking off one 2x14 section of the dual header, I carefully removed seven of the straight pins from the inner section, and replaced them with 7 right-angle pins that I carefully removed from the right angle header. I also removed the two pins that are next to VIN and 3.3V on the inside. I trimmed the right angle pins to cover just the pads on the underside of the Teensy3.x. I then did the same thing to a 2x7 section. The result looks like this (sorry for the photos, but none of my cameras work well closeup):
Teensy3.x-1-800x600.pngTeensy3.x-3-800x600.png


I then place all of the headers in the Teensy3.x:
Teensy3.x-4-800x600.png

And solder everything with a fine-tipped soldering iron. The dual headers add some mechanical rigidity, and allows the Teensy3.x to be used with a socket.

I've also created an Eagle Library that uses the pinouts for the device.

It takes a little work, but if you like to re-use your Teensy3.x, it may come in handy.
 
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Nice work. I would think it would take a lot of force to remove that from a header socket, at least the kind I have.
 
Updated setup

I've been playing with this concept a little more, and this is my latest iteration:

Teensy3.1-with-reset.png

I'm now using two 2x14 headers, wth the appropriate pins removed or replaced with right-angle pins as described above. I've used an exacto knife to carefully carve out an opening to accomodate the RTC crystal, and included a right angle pin that is used to bring out the RESET pad.

I find that carefully tinning the pads and right-angle leads makes the soldering go much smoother.

I've updated my EAGLE library part to include the RESET breakout. The updated library is here
 
I've been playing with this concept a little more, and this is my latest iteration:

View attachment 2558

I'm now using two 2x14 headers, wth the appropriate pins removed or replaced with right-angle pins as described above. I've used an exacto knife to carefully carve out an opening to accomodate the RTC crystal, and included a right angle pin that is used to bring out the RESET pad.

I find that carefully tinning the pads and right-angle leads makes the soldering go much smoother.

I've updated my EAGLE library part to include the RESET breakout. The updated library is here

Thanks for sharing this.

How long are your right angle pins? It looks to me like you need about 5mm or so from the centre of your reset pad to the Teesny 3.1 reset pad. (I am trying to find an alternative part to the Adafruit one)

Regards,

Les
 
Thanks for sharing this.

How long are your right angle pins? It looks to me like you need about 5mm or so from the centre of your reset pad to the Teesny 3.1 reset pad. (I am trying to find an alternative part to the Adafruit one)

Regards,

Les

As near as I can tell with my 63-year-old eyes, they are about 7mm on one leg and 7.5mm on the other. I just ordered a large quantity from china, and trim them to the correct size with a sharp set of cutters.
 
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As near as I can tell with my 63-year-old eyes, they are about 7mm on one leg and 7.5mm on the other. I just ordered a large quantity from china, and custthem to the correct size with a sharp set of cutters.

Interesting, they don't look that long from the pictures and I couldn't see a data sheet. Most of the ones I am finding only have a 3-4.5mm tail.

I'll keep looking.

Regards,

Les
 
Interesting, they don't look that long from the pictures and I couldn't see a data sheet. Most of the ones I am finding only have a 3-4.5mm tail.

I'll keep looking.

Regards,

Les

After I assemble the pins, I trim then to size with a sharp set of cutters.
 
after I replaced the 7 straight pins with the right angled pins, now the header won't sit flush on the teensy.
did you do some adjustment to the plastic so the header sits flush on the teensy pcb?
this is going to annoy the heck out of me if I solder this knowing the header plastic is not flush on the teensy.

update
ok, if I push harder on the right angled pins with a long nose pliers until it sinks into the plastic, I am able to get the header to sit flush on the teensy. :)
 
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For the eagle file, I see a problem with the thru holes. I think there should be through holes all the way up for both rows so you can solder your 2x14 female connector so you don't need to alter it and for a cleaner look. Also, I think there should be a second package that has thru holes for both this method and the method using 2x7 smt header so users of pcb have the option to choose which method they prefer.

BTW, it is way easier to carve the notch for the crystal using dremel. You have better control and the result is cleaner.
 
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For the eagle file, I see a problem with the thru holes. I think there should be through holes all the way up for both rows so you can solder your 2x14 female connector so you don't need to alter it and for a cleaner look. Also, I think there should be a second package that has thru holes for both this method and the method using 2x7 smt header so users of pcb have the option to choose which method they prefer.

BTW, it is way easier to carve the notch for the crystal using dremel. You have better control and the result is cleaner.

Here are all of the Teensy3.x eagle libraries that I've used at one time or another. They come with no guarantee, so use at your own risk.

View attachment TeensyLbrs.zip
 
I went ahead and soldered the headers to the teensy. And it worked fine. This is the best solution for me to get the bottom pins connected while keeping the small footprint and would recommend this over any other methods. And I can see how the double row header plastic helps to reinforce the pins soldered to the bottom pads. I know there is another thread that has other options to connect the bottom pads, but literally doubles the footprint, which I think defeats the purpose of using a teensy.

EF046114-838A-4FAB-932D-E3EE7A474CFF.jpg

I initially planned on connecting every single bottom pad, including the USB D+ and D-, but in the end, opt for the minimalist approach and just connected the 10 digital pads since those are all I need to use in my project.

I used smd solder paste on the smd pads, but I think tinning the pads with a little solder will work just fine. In hindsight, I think I should have snipped the D29-D33 pins shorter before soldering.

I thought of creating a breadboard adapter pcb for this, but decided to just build one from a protoboard.

BTW, the eagle library you posted uses 80 mil annular rings. I had to reduce the size to 40mil drill hole and 76mil annular ring since I use 10mil trace in order for traces to pass through between pads.
 
I had ordered pcb from oshpark for this right when 3.1 was about to be discontinued. I would not have placed the order if we had heads up 3.1 will be discontinued and pads placement changed, anyways.

This is what it looks like. It has reset switch, USB connector, RTC battery backup, 3.3V regulator and SD card socket.
IMG_1883.jpg


without the teensy. I had routed D+ and D- reversed, so I had to cut the trace and rewire. :)
IMG_1881.jpg


bottom view. I mistakenly thought my SD MOSI and MISO were switched, turned out the trace was right, so the cut on the SD trace was not necessary.
IMG_1882.jpg
 
this is what the teensy 3.1 looks like, bottom view. I have inserted and removed this from a socket at least 100 times already with no problems.
Notice the yellow Kapton tape I used to cover the other test points that were in the way.
IMG_1880.jpg


I still think this is the best solution to breakout all the bottom pins. And it is completely reversible if you do not want the pins later on your teensy.

Too bad 3.1 is discontinued. I think the angled pins can still reach the new 3.2 reset and D+ and D- locations, but not sure if my current breakout board will work or not. Maybe it will with minor trace cut and rewiring and some Kapton tape.

edit--
I just noticed in my earlier post picture I did not have the reset and D+ D- pins yet on the teensy.
I simply slid the pin header plastic up, added more pins and slide the plastic back. Hence this mod is completely reversible or can be altered if you later needed a different configuration.
 
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I finally had an opportunity to set up a Teensy3.2. I found the easiest way to get the reset pad connected was to simply maintain the current configuration, and tack-solder a 30ga. piece of wire between the pad and the leg (I left the crystal out to make it easier to see, I added it later):

Teensy3.2.jpg

I also followed onehorse's advice, and got the same rework station. It makes adding the inner connections a snap.
 
wow, this whole difficult project could be alleviated with a bigger Teensy with more SIP pads. If there is a schedule on that I would rather limit my projects to the SIP pins at hand until that happens.
 
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