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Originally Posted by dsirovica
I didn't discuss the details of your open source proposal with TI, just high-level.
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Then their response was predictable.
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I like your modular approach especially if the modules can find wider markets. But I wonder if we are slicing and dicing too much already. As you pointed out a modular approach is more expensive than an integrated one (everything else being equal).
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The problem with integration is that you force the slicing of the bread just the way you offer. If integration alone was able to secure a large market segment they'd have achieved that long ago but when they did the knock-offs chewed it apart again.
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I believe we could go the other way. That is a more flexible Jaguar. As we have seen in our technical analysis of the Jag (elsewhere on these posts), the power can easily be increased to 100A ++ just by adding another Mosfet per H-bridge leg, and setting different thresholds on the current sensing software. The BOM cost of that would be minimal. I was browsing through the 800 page Stellaris manual – that is a powerful and very well designed beast! It is made to run RTOS, abundant interrupt levels, it has an amazing brown-out hardware support – it seems the FIRST software image does not make much use of any of this. Therefore I believe one could make a Vic shaped Jag on steroids that would serve the 10A-150A market. And if it is just one SKU I believe the cost could be driven down to below $100. Further just like with the Vics and CRios, FIRST could obtain an additional discount for bona-fide FIRST users. But there must be other markets, and I would think there would be with such a flexible and robust unit. It will kill the Vic though.
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As I've stated previously. I intend to move forward regardless of such an attempt. I think the Jaguar could be fixed. However, in doing so you'd be ignoring that TI couldn't massively sell the unit when it was totally open and sourced through DigiKey on any scale besides FIRST. As I've mentioned in private, custom robotics solution providers are not likely to simply accept the Jaguar (issues or not) as is. These users usually seek to lock in markets not open the markets up. Worse this isn't exactly a mil-spec product either so there goes most production aerospace and military application.
So even with the fixes, yes it'll satisfy FIRST, but I believe whom ever you convince to do that will be in the very same situation that TI put themselves in when they absorbed Luminary Micro. A new coat of paint with a target out of reach.
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On FIRSTs requirement of power control – why could that just be done by specifying the resettable fuse values for each type of motor? Then the judges would check that at inspection time.
Dean
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Why bother to measure current if you do that?
Also, generally self-reseting fuses rarely trip at the currents listed on them, short much higher currents can flow.
Even using the Stellaris and it's speed means that for a very, very short time a larger current could flow (it's just that the motors generally won't be able to make it happen).