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Comment by quanto | Hacker News Reader

I agree. The wire itself is not where the precision is. It's the reciprocating mechanism done by the wire.

Regarding price, my point still stands that wire is not cheap enough to motivate its use. Your link actually proves my point (1.6 USD/30cm). Pager/toy motors are costing cents.

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The margin on this stuff can easily be 1000% when sold to hobbyists. Or rather costs of cutting the wire to length, packaging it, warehousing, etc. For a small number of orders, I wouldn't be surprised if this was done mostly by hand. Plus there is some risk the stock sells too slow, since it is so niche (compared to ESP32 or sensors). That's all priced in there, plus some healthy margin.

While the pump manufacturer just puts a 1000m spool in his assembly line every few hours.

It seems absurd that hair thin thread costs more than a whole assembly of permanent magnets and copper coiled in a stator. Just thinking from first principles. Whats driving the cost? The processing? For scale, Omnipod only makes this one product and they're on the S&P 500 because they sell so many of them. I'd guess 10 cents in bulk but who knows. It's a SparkFun link for DIY hobbyists. They're not charging the bulk rate. They have to make a margin.

But maybe it is more expensive. Then they probably choose it for the reliability, and a simple and quiet design. Or perhaps the button batteries don't have the energy to drive a pager motor.

At high enough volumes, cost becomes the cost of the raw materials. NiTi wires are obviously made of Ni and Ti, both of which are ~3x the cost of copper.

If you can design the wire to require 3x less material than the motor approach, it will win.

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