How to Remove A Shield/Cape/Head Without Bending Pins? Arduino-like

Electronics
#1

Hi Group,

I need to come up with some fixture which will allow a tester to remove an Arduino-like shield from the Arduino-like base without bending the pins. Now, you may be thinking this is piece of cake if you do it slowly, but my board (the HYDRA-X20) has many more pins than the Arduino Uno-like counterpart, and as of today I have not been able to remove my Head Boards without bending pins.

I am thinking there must be a mechanism where I can have one lever, but it somehow actuates two tongues which come up at the same time, applying equal force on the top board’s sides so that all the pins are released at the same time. This way, pins shouldn’t bend.

Mechanics have always been my weak side so I can’t envision this. I know this has to be kindergarten material for mechanic savvy folks. What can you recommend? Thanks!

BTW, I can design the final product. What I need at the moment is some kind of pointer as to where to look at pictures to get the idea how to draw it and then machine it.

#2

Pictures of the parts in play might help. You’ll probably get some good responses without them, but they can only help ensure we’re all on the same page. …

#3

I can take pictures of the two boards, but picture an Arduino and a Shield. With the Arduino fixed to a metal plate, how do you apply forces on the top board so that the board comes off without one side coming off before the other? If one side comes off before the other, pins will bend. This is what I must ensure does not happen.

EDIT: I envision there must be some sort of lever mechanism where with a single handle, you can make two levers move in unison so that the top board is ejected upwards. But what is that mechanism? That’s where I am rusty!

#4

In short, and without picturing an Arduino and a Shield because I don’t know what those look like outside of Google images, (in other words, if they work like I’m guessing they do, essentially “sandwiching” together, so that what you need is a separater) envision a corkscrew, y’know, the kind where you screw the curlicue into the cork, the wings on each side rise, the bottle rests on the mouth, and when fully seated you pull down on the two wings to remove the cork.
Now, in stead of the curlicue for the cork, envision that the bottle rest and the “corkscrew” parts have 4 arms; those on the “bottle rest mouth” push against the bottom; those on the"corkscrew" pull up against the top board, one on each of the 4 side of the boards. Fenagle the 8 arms in between the boards, pull down on the wings, pressing the 2 pieces apart, and robertsyeruncle.

I suck at drawing, too, or I’d try to draw up a diagram. It looks great in my head.

#5

Seriously? The only response here was my shitty suggestion? Maybe it was a busy weekend for Arduino loving folks, so I updated the category to electrical and added keyword Arduino to the title. Maybe now it’ll get attantion from someone who actually knows what is being talking bout, unlike me…

#6

I most certainly will not claim to know what I’m talking about but I am willing to share some personal observations from my limited experience.

  • Pushing works significantly better than pulling. Which means using something resembling a pry-bar.
  • Metal is a bad choice. Everything gets damaged. The board. The traces. The components.
  • Plastic is a bad choice. It just bends.
  • Hardwood is a good choice. I have yet to cause any damage with a wooden pry-bar.

So, when faced with separating two troublesome boards, I make a pair of pry-bars from hardwood (or Baltic Birch plywood if I don’t have hardwood on hand).

#7

Explosives. Only way to be sure.

1 Like
#8

Aha! Great info! I have been using a screw driver, pens and different implements as “pry-bars”, but the material findings help a lot! Maybe if I make it out of a plastic like delrin it will be strong enough not to bend.

The cork screw mechanism is something to seriously consider. Will need to somehow morph some gears into the mix, which I must admit is something I have never had much luck with. But this mechanism is key because in the same fashion you don’t want the cork to break apart because the force is not fully upwards, I do not want my pins to bend because the force is not fully upwards.

The brainstorming continues! I think I should just start drawing the darned fixture and see where that goes, heh heh

#9

The only ones I have ever had much of a problem with bending pins is the Arduino Mega/Duo’s where they have a set of dual inline headers that are perpendicular to the normal two rows.

Frankly, I just pry them a little at a time, in multiple locations, with my fingers until they separate. This even works with the above mentioned mega shields; however, those are just tougher.

For Pi shields, I have always found they separate easily. No experience with beagle bone capes, but would imagine the same principals apply.

All that said, back in the days when integrated circuits were offered in large (40 & 64 pin) dual inline packages, they made a device called a chip puller. Looked a bit like this:

ic_puller.jpg872×512 76.7 KB

Wouldn’t be too hard to make a custom four sided version of something like this for each style board you wanted to pull. The only thing you need to achieve is realatively even force on each side of the board.

#10

Thanks to all for the suggestions! Definitely with all of this input I was able to get some inspiration and put this guy together. It is no cork screw (which would have been way harder to implement and I am no mechanical engineer) but it works, so at the end that is the only thing that matters.

Hydra-X_Head_Separation_Fixture.jpg816×612 192 KB

It is kind of hard to visualize with a single picture, but basically, the middle plank has the body board (Arduino like board) screwed into. It goes up to meet with the head (or cape/shield, whatever we want to call them) and the interface is made. Once the test is complete, you pick up the fixture with both hands and push the middle plank and bottom plank together. The top plank is grabbing the head so it can’t move and the separation takes place without bending pins. It also allows for the head board, which is a sellable product, to walk unscathed from the process (no marks, scratches, etc).

2 Likes
#11

Try popsicle sticks, THEY have good use because you can use a dremel to
mold then to whatever shape you need.

#12

I imagine you would need to glue some of them together in order to avoid cracking them? Sounds like a plausible solution as well!

In this case, however, I needed a production tool because these boards will go into the marketplace and it is crucial there are no scratches, bends or blemishes of any kind. Popsicles, being wood, would most likely end up taking the hit, but it is my impression I might still end up with a few bent pins. Unless you get good at prying both sides at the same time, but we didn’t have any sacrificial board to give this route a chance.

BTW, I only made one of these tools and I gave it to the factory so whenever I need to pry my development boards apart, I am back to pens and all sorts of implements. But in my case it is not the end of the world if I end up making every pin look like a candy cane :wink:

#13

For a production jig you are better off creating one using pogo pins. The problem with your set-up in a production environmet is that the pin sockets on the main board have a limited life span and will wear out with repeated insertions/removals.

If you choose to use your current set up, just remember when you start getting frequent failures, check your main board first before discarding your ‘production’ boards.

[Source of pogo pins in small quantities][1]

[1]: https://www.sparkfun.com/search/results?term=pogo+pins f2f

#14

Yep. I don’t get it. Looks great, though, and if it does what you need, I’m excited for you. Now that you’ve designed/made 1, another should be much easier if desired, and probably even improve the design.
Congrats!

#15

Here’s my two-cents on tooling. Actually, less than two-cents, so it’s worth what is being paid for it.

Is the purpose to install the shields, test them, and then remove them? If so, then a better approach might be to make board with short pins just long enough to engage the shield plugs. Have this board wired to the Arduino board. This assumes you have a number of boards to test to justify the fixture.

Because the pins are short, less stress on insertion or removal making bending less likely and easier to remove. Also, with no circuits on the board under the shield being tested (just pins which are usually around edge) “Push Plate” could be made that would push from the center, have soft rubber like coating so as to not mar the circuit board.

#16

Explosives! :slight_smile: :slight_smile: :slight_smile:

2 Likes
#17