http://www.kickstarter.com/projects/194 ... orite-game
Apparently the 40 sensors are cheap, but I wonder how much installing them, the cabling, and the microcontrollers will cost.
40 sensors and 9 microcontrollers
- blazespinnaker
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40 sensors and 9 microcontrollers
Gear VR: Maybe OVR isn't so evil after all!
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- Binocular Vision CONFIRMED!
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Re: 40 sensors and 9 microcontrollers
Needing 9 microcontrollers makes it sound like it's not very optimized. I wonder if this is just a prototype.
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- Golden Eyed Wiseman! (or woman!)
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Re: 40 sensors and 9 microcontrollers
Low-end microcontrollers are cheaper than many MEMS sensors. Generally it's more cost effective and easier to implement a uC in a sensor node due to limited number of I2C addresses available for a given sensor, or the need to control the chip select pin on a sensor using SPI, otherwise you would need additional components (more expensive than a uC) or more conductors in your cabling.
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Re: 40 sensors and 9 microcontrollers
The sensors are almost free, because they are capacitive sensors, meaning they are just a piece of metal foil connected to a microprocessor input pin through a resistor. The only reason for needing a bunch of microprocessors would be to get more input pins, although that could also be accomplished by using a single microprocessor and some shift register chips (or another input multiplexing method). Microprocessors are very inexpensive these days, and perhaps easier to obtain in some cases, so not much extra cost to use a bunch of them, especially if that simplifies firmware development for the Virtuix team.
Simple capacitive sensing:
http://playground.arduino.cc/Main/Capac ... n.CapSense
That example shows one input pin per sensor. One common output pin can drive many sensors. Your body forms part of the capacitor when it is near a foil plate, and the software times how long it takes to charge that capacitor to determine how close your foot is to the foil. Simpler software only needs to know if your foot is over the sensor, not how far away it is...
Simple capacitive sensing:
http://playground.arduino.cc/Main/Capac ... n.CapSense
That example shows one input pin per sensor. One common output pin can drive many sensors. Your body forms part of the capacitor when it is near a foil plate, and the software times how long it takes to charge that capacitor to determine how close your foot is to the foil. Simpler software only needs to know if your foot is over the sensor, not how far away it is...
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Re: 40 sensors and 9 microcontrollers
Ah, I figured they were talking about MEMS sensors (I didn't see mention of anything on that page, and I didn't watch the videos). Still, microcontrollers can be cheaper than devices such as I2C IO port expanders, and not significantly more expensive than a typical shift register, while making implementation easier.
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Re: 40 sensors and 9 microcontrollers
uControllers may be cheap, but if the Omni takes off that's money wasted times thousands on having 9 uControllers compared to using one with more power/IO ports. I wonder how they're getting all 9 to communicate with the host computer, 9 separate USB connections?
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Re: 40 sensors and 9 microcontrollers
Perhaps one master controller with USB port, plus 8 slave processors (acting as IO expanders).Krenzo wrote:uControllers may be cheap, but if the Omni takes off that's money wasted times thousands on having 9 uControllers compared to using one with more power/IO ports. I wonder how they're getting all 9 to communicate with the host computer, 9 separate USB connections?
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Re: 40 sensors and 9 microcontrollers
Would it be cheaper still to attach a permanent magnet to the sole of the shoe and when it moves past one of N coils of wire it creates an EMF in proportion to the rate of change of magnetic flux (speed the magnet and therefore your foot is moving).
I can't quite remember the physics but I believe it was Faraday's Law.
I can't quite remember the physics but I believe it was Faraday's Law.
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Re: 40 sensors and 9 microcontrollers
Possible, but you would need a substantial number of coils.Haloar wrote:Would it be cheaper still to attach a permanent magnet to the sole of the shoe and when it moves past one of N coils of wire it creates an EMF in proportion to the rate of change of magnetic flux (speed the magnet and therefore your foot is moving).
I can't quite remember the physics but I believe it was Faraday's Law.