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particle-iot / core

Hardware design files for the Spark Core, a tiny Wi-Fi development kit.
https://www.spark.io/
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Find a button that is more widely available (and also inexpensive) #26

Closed zsup closed 11 years ago

zsup commented 11 years ago

The button we originally had on the Core was too expensive. The button we're currently using is inexpensive, but not widely available.

We need to find a new button that is both inexpensive and widely available.

technobly commented 11 years ago

I'm working on building one of the v0.2 boards and just ran into this problem today... the button that's on the board currently is also kind of narrower that most buttons out there. If I run into something appropriate I'll let you know. What's your price point?

Here's an out of the box idea... currently there are two buttons on the board... maybe you could just put one on there that was larger (more common) and save money that way. Most of the time you would never use the reset button on an Arduino. Not sure if the Core requires the reset button for initial setup or anything... but I would think just pulling the power would be pretty easy. So you could ditch that for the convenience of an onboard user button...or, maybe there's a way to make the button function as a reset button first... but be configurable through software as a user button?

Since I'm talking about parts... does the external Flash memory need to be 75MHz or is 50MHz good enough which is cheaper.

zsup commented 11 years ago

It turns out that we can use any of the tactile buttons from this series: http://www.digikey.com/product-detail/en/KMR441NG%20LFS/CKN10286CT-ND/2296967

There's a bunch of very similar switches that just have different heights. We won't use these in manufacturing in China because they're expensive, but they should work for building your own boards, because the footprint is roughly the same as what we've got on the board now.

zsup commented 11 years ago

Oh and for the flash memory, 50Mhz should be fine

technobly commented 11 years ago

I had that exact one open earlier today... the footprint is about 0.4mm wider overall. I guess that's not much, but I worried a bit if the switch would bump into neighboring components.. I don't have the datasheet for the switch on the Core currently to compare. I'll just order some and see if they work. It's not like I really need the switch anyway.. but it would be nice to put together a local BOM with all the parts from Digikey and Mouser. Thanks for the info.

Oh and for those C&K switches, make sure to get the "NG" in the part number like you have.. it gives you a switch with no extra ground tab.

zsup commented 11 years ago

I think it should be fine, but if you find that it doesn't fit when you put it together, let us know and we can shift things around a bit so that it works for both buttons.