Rationale for not producing pinless Xenon


#1

Hi,

I’m using the Xenon in a product and the pins are just awful - they add hugely to the package height and stop me from automating the build. I’ve discussed this a few times on here so I won’t beat that drum again, but TL;DR without pins the Xenon can be automatically surface mounted - instant SOM.

Instead of asking you to do this can someone at Particle provide a rationale as to why you don’t do this?

There’s been talk about an SOM for months but nothing exists, not even a public design. A pin-less Xenon has almost all of that functionality at zero design time and zero setup cost. If you were to remove the bottom UFL, the Li-Po and program connectors it would be as flat as any SOM. I just don’t get why you wouldn’t ship it at least pin-less as as a stopgap industrial solution. Not to mention that I’ve looked at the Boron B series and honestly using a narrow-trace card slot leaves me pretty cold in an industrial application. I’d way rather just surface mount a module for reliability - my product gets physically slung around a lot.

-Mark


#2

Part of the reason discussed in other topics was the fact that the nfc antenna connector is on the bottom of the xenon, and could cause issues. The seems trivial and for those who buy it they should know this when buying and designing around it.


#3

For prototype devices I use short headers and cut down the pins - not something you would do in production.

I might add that you could through hole mount using the existing pins, then cut off the excess pin length. The PCB could be designed with cutouts/holes to avoid the need to remove the NFC UFL and to handle the Li-Po battery connector pins.

Personal experience with Photon is that using with headers has given us the flexibility to swap out devices when there is a problem and means the PCB assembler does not need to be supplied with devices.

The X-Series SOMs are on their way and using the M2 form factor - these slot in and are then secured with a screw.


#4

Admittedly the nfc antenna connector is suboptimal but here’s my board layout ->


#5

Sorry, got a phone call and mistakenly posted the last piece without context…

I remove the headers – but it’s time-consuming and error-prone since I have to trim all the pins and a copper layer may easily flake when the header is laboriously pulled off. Then I hand-solder the IC in and trim the pins again. I live with the LiPo and programming heights but wish they weren’t there.

I really don’t want an M2 card for the industrial xenon, but I suppose I could change my mind when I see the design. I use a cheap overseas board house and my trace sizes/spacing are large so they can be off and still work. Also, my product has air-holes and is designed to be harshly slung around in dusty areas.

Thanks for listening.

Mark


#6

One reason why they might not “just make one without components X Y and Z” is that would mean an entire separate production run, yet another SKU to manage, ship and support, and a hassle overall.
Seeing as there will be dedicated SOM modules, it’s probably best to wait for those than spin up a new design for half a xenon.


#7

I have seen that as a rationale, but it’s not expensive to create and maintain a SKU and the change to production is ‘don’t do this step’. Meanwhile I would have been able to ship a better/cheaper product for a year instead of ‘wait for those’. I’d even pay more for the device without pins - it saves me money.

As for support - I’m dubious that supporting an identical product, but without pins, adds to the support load.

I find the choice not to do this puzzling.

With all that said, I’m still in the ecosystem because the Xenon is one of the best-engineered modules I’ve ever seen, it fits my electrical needs perfectly, and I sure don’t want to duplicate it.

-Mark


#8

While the technical part might not be as challenging, though they’d still need to be tested and whatnot.

As for the SKU, that’s separate shipments, double inventory (costs), additional 3rd party logistics and supplies. It’s not just ‘add the number to the store’.
I’m not 100% sure what comes into play with maintaining a new SKU, but it’s not just a flick of a switch.
It would also send a confusion messaging about the future of the xenon, since the plans for the SOM exist already. It will be there, though a definitive ETA is not available quite yet.