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> 1) How would wiring to you processor work? My (relatively limited) experience is that this is what really makes wearable projects obnoxious. Even if you hav

by saulrh 2y ago

> 1) How would wiring to you processor work? My (relatively limited) experience is that this is what really makes wearable projects obnoxious. Even if you have a chip with a tiny footprint, you either put it on a breakout board that isn't tiny or you spend twenty hours soldering nearly microscopic bits of magnet wire to it. It's the same for the piles of passive components and peripherals that every project requires, the voltage regulators and smoothing capacitors and power transistors and stuff: You either attach everything to a big PCB or you're faced with a spaghetti nightmare of point-to-point wiring that makes "normal" dead-bug circuitry, the kind you might find embedded in a block of resin for aesthetic points, look like a walk in the park. Flexible processors don't necessarily solve that problem, but they definitely demonstrate that flexible circuits in general are advancing in useful ways, better signal quality and longer runs and better process yield. The bigger these things get the better they are for replacing that mess of integration spaghetti that I always see DIY wearable projects suffering from. (I think that industrial wearables typically solve this by concentrating everything complicated down to a rigid brain-box, c.f. smart-watches or those heated jackets that have a socket for a power tool battery in the pocket.)

marshray 2y ago
> or you spend twenty hours soldering nearly microscopic bits of magnet wire to it. A real chip would only need two or three contacts to vastly outperform thing demonstrated here. These would probably not be soldered, they would ideally be bonded directly to the chip. Imagine a near-microscopic 4-ball BGA on a bit of flexible PCB, except the PCB material can flex in multiple axes simultaneously.
- eternityforest 2y ago
  Isn't that kind of like how RFID labels work? That's probably the most common use case for flexible anything at the moment, and they work great
ChuckMcM 2y ago
You can look at die attach[1] which basically solders to pads on the circuit board (no magnet wires required :-)). [1] "Die Attach Comes to PCBs" --- https://www.eeweb.com/die-attach-comes-to-pcbs/ https://www.eeweb.com/die-attach-comes-to-pcbs/
- kevin_thibedeau 2y ago
  That article describes traditional chip on board construction that has been in use for decades. Buried at the end it mentions wire bonding as the final step. i.e. pads are up. Flip chip mounting requires careful attention to thermal expansion coefficients. You're not going to do that on any run of the mill cheap board or flex materials.

by saulrh 2y ago

marshray 2y ago

> or you spend twenty hours soldering nearly microscopic bits of magnet wire to it. A real chip would only need two or three contacts to vastly outperform thing demonstrated here. These would probably not be soldered, they would ideally be bonded directly to the chip. Imagine a near-microscopic 4-ball BGA on a bit of flexible PCB, except the PCB material can flex in multiple axes simultaneously.

eternityforest 2y ago
Isn't that kind of like how RFID labels work? That's probably the most common use case for flexible anything at the moment, and they work great

ChuckMcM 2y ago

You can look at die attach[1] which basically solders to pads on the circuit board (no magnet wires required :-)). [1] "Die Attach Comes to PCBs" --- https://www.eeweb.com/die-attach-comes-to-pcbs/ https://www.eeweb.com/die-attach-comes-to-pcbs/

kevin_thibedeau 2y ago
That article describes traditional chip on board construction that has been in use for decades. Buried at the end it mentions wire bonding as the final step. i.e. pads are up. Flip chip mounting requires careful attention to thermal expansion coefficients. You're not going to do that on any run of the mill cheap board or flex materials.