A few days ago we reported on a new product for owners of the Raspberry Pi Zero, a set of solderless header pins that had a novel installation method involving a hammer. We were skeptical that they would provide a good contact, and preferred to stick with the tried-and-trusted soldered pins. It seems a lot of you agreed, and the comments section of the post became a little boisterous. Pimoroni, the originator of the product, came in for a lot of flak, with which to give them their due they engaged with good humor.
It’s obvious this was a controversial product, and maybe the Hackaday verdict had been a little summary based on the hammer aspect of the story. So to get further into what all the fuss had been about I ordered a Pi Zero and the solderless pin kit to try for ourselves.
The plan was to install the pins on a Pi Zero, and then to simulate the life of a typical board in the hands of an enthusiastic youngster by repeatedly plugging and unplugging a HAT. To that end a GertVGA board stood in for a HAT, as it was the only Pi peripheral I had on hand with the full-sized connector.
Opening the bag from Pimoroni, I found a set of their trademark lasercut plastic pieces, two nylon bolts, and both a set of push-fit pins and a push-fit socket. No instructions are shipped with the parts, instead they send you to their website product page upon which they have their video showing how to assemble the parts and fit the connector.
The pins themselves are just the same as their soldered counterparts at the long end, but the short end that fits into the board differs sharply from its more conventional cousin. Each pin has been flattened and pierced, into a shape something like the eye of a hand sewing needle.
The whole connector does not pass through the holes in the board when it is offered up to them, instead it sits proud of the board and can not be readily pushed through them. Straight away I can see the task facing the jig and hammer, to force these pins into the holes, which are not quite big enough to take them.
The plastic parts form a jig that holds the Zero in place and provides both a piece of plastic as a drift on top of the pins and a couple of layers below the Zero to take the load. Meanwhile the two bolts line up the holes in the various parts with the holes in the Zero, and keep everything in place through the pin fitting process.
All this brings us neatly to the hammering. Their video shows a succession of light taps with a pin hammer along the length of the jig, so our Zero was put in place and the hammering began. Each set of taps along the length of the connector advances it a very small amount, so I had to have several goes at it, examining the progress between each one. At one point the connector had progressed further into the board at each end than it had in the middle, so it was necessary to hammer slightly more in the center. Another concern developed: there was a very slight flex in the board. Were I to do a second one I would be as careful as possible to minimize this. However the flex disappeared once the connector was properly seated along its entire length. The hammer action required was a very light touch indeed, more of a tap than a stroke. It is probable that had the same technique been used with a panel pin in a piece of wood, it might not have hammered it in very far at all.
You can see the whole process in the video below. It’s certainly pretty quick to fit a connector in this way, I doubt I could match it with solder.
When the Zero was removed from the jig, it could be seen that the pins were well seated in the holes, and could not be moved. A small Python script was run that created a square wave by taking a GPIO pin high and low, and it was found to be working on all available pins.
All well and good, I had fitted the pins, and they worked. However the point of a set of pins is that they should work reliably for the lifetime of the device. I could not hand it to an eager child for a year’s hard service because I didn’t have a spare year for the test, but I could simulate heavy usage by repeatedly connecting and disconnecting a peripheral. A GertVGA board stood in for a HAT for this purpose, as it was the only one I had to hand with the full-size Raspberry Pi connector. Visitors to Oxford Hackspace’s social night were treated to the spectacle of a Hackaday scribe repeatedly plugging and unplugging the GertVGA from the Zero over a hundred times until her fingers hurt. The speeded-up video below shows only a fraction of the process.
After all the repeated GertVGA plugging, the pins were still rigidly attached to the Zero and my python script rewarded me with a square wave as I tried it on the GPIOs. So I’d fitted the pins, and they had survived an evening of moderate abuse with connectivity intact.
In conclusion, it’s fair to say that we’re in for a bit of word-eating here, as the pins have proved to be both straightforward to fit and reliable enough for repeated use. Soldering would probably still be the personal method of choice and their installation requires real care, but these push-fit pins represent a viable alternative. The full kit with the jig weighs in at £6 (About $7.50), which is a pound (about $1.25) more than the Pi Zero, but it’s worth remembering that it includes a socket as well as the pins, and that while a soldered connector would be cheaper, the cost of solder and iron would be much more if you do not already possess them. It’s also worth putting that into perspective, the Pi Zero is so absurdly cheap that it makes almost all accessories look pricey.
It would be interesting to see whether the tension between the pins and the edge of the PCB hole is such that the hole stretches or relaxes over time, and whether that might cause issues if the connector was used over years. The fix would be a simple case of soldering the connector, but it’s possible that this might be a problem. However this does not take away from the instantaneous results that most people buying this product will be looking for.
If you have tried this connector on your Pi Zero, let us know how you got on in the comments. Please remember though, uninformed criticisms have already been done to death in the comments for the previous piece linked above, so if you want to weigh in please make sure you have something new to add to the discussion.