Fast microcontroller clock

What is the fastest microcontroller board to buy ?

I need to measure distance with radio waves.

How deep are your pockets?

What are the shortest and longest distances you need to measure?

The Teensy 4.0 (ARM M7 at 600 MHz) is possibly the fastest that is well supported by the Arduino development environment.

That said, people have measured distance with radio waves (radar) long before microcontrollers or digital electronic computers of any sort existed, so perhaps you need to better constrain the problem, the proposed approach to solving it, and specifics what the microcontroller needs to do.

You can measure distances, with radio waves, using a 8Mhz Arduino Pro Mini.

Cant see why you would need a faster microcontroller .........................

PaulRB:
How deep are your pockets?

What are the shortest and longest distances you need to measure?

I dont wonna give allot of money , 50$ and less ,
I hope there is somting for 25$

3m-200m

MrMark:
The Teensy 4.0 (ARM M7 at 600 MHz) is possibly the fastest that is well supported by the Arduino development environment.

That said, people have measured distance with radio waves (radar) long before microcontrollers or digital electronic computers of any sort existed, so perhaps you need to better constrain the problem, the proposed approach to solving it, and specifics what the microcontroller needs to do.

Traying to make some project , to get it position ,… long story , and i dont wonna use gps …
I need high accuracy , is there another way to get high accuracy position besides gps , radio waves and laser?

srnet:
You can measure distances, with radio waves, using a 8Mhz Arduino Pro Mini.

Cant see why you would need a faster microcontroller …

I read somwhere:
"
The use of a 30MHz crystal does not allow creating a very precise time base. The aftermath will be an error on the distance about ±5m. Increasing the frequency of the time base will improve the accuracy: The higher frequency, the more precision."

So if 30 mhz is not enough with 8 mhz pro mini like you said i will get big distance error

So if 30 mhz is not enough with 8 mhz pro mini like you said i will get big distance error

That would depend on how you made the measurement.

I suggest that you do some research how that measurement might be made, before deciding on a microprocessor. You will find that some additional equipment is involved.

davax: I read somwhere: " The use of a 30MHz crystal does not allow creating a very precise time base. The aftermath will be an error on the distance about ±5m. Increasing the frequency of the time base will improve the accuracy: The higher frequency, the more precision."

So if 30 mhz is not enough with 8 mhz pro mini like you said i will get big distance error

What considerations have you given as to how this 'measurement' will actually be achieved, what radio wave and by what means ?

Measuring the time of flight of a radio wave is not so easy. The 2m resolution you apparently need represents a flight time of 6.7ns, so by some magic you would need transmitter and receiver locked together in time to that sort of accuracy, definetly not easy.

In addition the frequency of the crystal used by a microcontroller is not directly related to the speed it runs at and hence the resolution that it could potentially time signals at. The SAMD21 processors for instance run at a clock speed of 48Mhz, using a 32.678khz crystal.

jremington: That would depend on how you made the measurement.

I suggest that you do some research how that measurement might be made, before deciding on a microprocessor. You will find that some additional equipment is involved.

srnet: What considerations have you given as to how this 'measurement' will actually be achieved, what radio wave and by what means ?

Measuring the time of flight of a radio wave is not so easy. The 2m resolution you apparently need represents a flight time of 6.7ns, so by some magic you would need transmitter and receiver locked together in time to that sort of accuracy, definetly not easy.

In addition the frequency of the crystal used by a microcontroller is not directly related to the speed it runs at and hence the resolution that it could potentially time signals at. The SAMD21 processors for instance run at a clock speed of 48Mhz, using a 32.678khz crystal.

Thanks for response, I still researching what is the best way to achieve that

Please any suggestion , how to make this would help. What microcontroller , RX TX ....

The only (low cost) device I can readiliy think of that can measure distance directly, using time of flight of 'radio waves', is the Semtech SX1280, its a 2.4Ghz LoRa device.

Details of the distance measuring here;

https://github.com/LoRaTracker/SX1280_Testing

And a Arduino library that supports the ranging capability is here;

https://github.com/LoRaTracker/SX12XX-LoRa

See the \examples\SX128X\Ranging folder for further details and a plot of the variances of measured distance at circa 100m.

srnet: The only (low cost) device I can readiliy think of that can measure distance directly, using time of flight of 'radio waves', is the Semtech SX1280, its a 2.4Ghz LoRa device.

Details of the distance measuring here;

https://github.com/LoRaTracker/SX1280_Testing

And a Arduino library that supports the ranging capability is here;

https://github.com/LoRaTracker/SX12XX-LoRa

See the \examples\SX128X\Ranging folder for further details and a plot of the variances of measured distance at circa 100m.

srnet: The only (low cost) device I can readiliy think of that can measure distance directly, using time of flight of 'radio waves', is the Semtech SX1280, its a 2.4Ghz LoRa device.

Details of the distance measuring here;

https://github.com/LoRaTracker/SX1280_Testing

And a Arduino library that supports the ranging capability is here;

https://github.com/LoRaTracker/SX12XX-LoRa

See the \examples\SX128X\Ranging folder for further details and a plot of the variances of measured distance at circa 100m.

Thanks

The only true time-of-flight high-resolution measurement using radio is UWB - ultra-wide-band, since you need huge bandwidths to get rapid pulse rise-times (a few nanoseconds). There are a number of UWB chipsets out there I believe, not sure how cheap they are now.

For lower bandwidths you have to use phase measurements for the fine resolution, and clever coding schemes. For instance this is what GPS does, despite the wavelength of the signals being much larger than the resolution, and the bandwidth limits being even more problematic.

If you were expecting a radio pulse from a standard RF transceiver module to be useful for this, consider the fact that even at 100kHz bandwidth the pulse start-time uncertainly is of the order of a microsecond or so, without repeated pulses and careful averaging. Radio waves travel 300m in one microsecond.