Author Topic: gyro output  (Read 1359 times)

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Offline roboninja93Topic starter

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gyro output
« on: January 08, 2012, 10:11:33 AM »
hello
for a quadcopter we use three gyros (yaw,roll,pitch)  for stability
i have read that kk controller boards are used which carry in built gyros and atmega48 microcontroller and have their own softwares...
is it possible to make a custom microcontroller board usig external gyros with a self made program?
and if we use the gyros how do we give its output to the microcontroller?
how do we program the microcontroller to read the gyro outputs and accordingly contol the motors throughthe ESCs( or motor driver)?
Thanks

Offline newInRobotics

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Re: gyro output
« Reply #1 on: January 09, 2012, 07:05:29 AM »
for a quadcopter we use three gyros (yaw,roll,pitch)  for stability
Wouldn't it be more efficient to use one 3 axis gyro? It's cheaper, uses less power, is lighter and possibly requires less interface pins.

is it possible to make a custom microcontroller board usig external gyros with a self made program?
Are You asking if it is possible to get uC and gyro separately, put them to one board and write own code for it? Yes, that's what people do :)

and if we use the gyros how do we give its output to the microcontroller?
There are digital gyros and analog ones. Digital gyros normally use serial communication (eg.: I2C) and analog gyros output voltage which should be read by ADC in uC.

how do we program the microcontroller to read the gyro outputs and accordingly control the motors throughthe ESCs( or motor driver)?
It depends on what type of gyro You use. Having that said, no one is going to write code for You, so better start looking for I2C and ADC tutorials, there are plenty of them online ;)

Good luck :)
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Kristian W

Offline roboninja93Topic starter

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Re: gyro output
« Reply #2 on: January 10, 2012, 08:54:01 AM »
thanx a lot for the reply
i am not getting gyros but i am getting a 3 axis accelerometer
can that be used as a stability device?
if yes then how do we use it?
thanks :)

Offline newInRobotics

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Re: gyro output
« Reply #3 on: January 10, 2012, 11:58:23 AM »
Best thing for stability would be 3-axis gyro and 3-axis accelerometer - that's what they use for self balancing machines (like segways).

Accelerometer data on its own is very noisy plus it is hard to determine speed of movement (say rotation in degrees per second) if You don't use gyro with it. Now, gyro on it's own tends to drift over time so data from it comes with an error; to compensate for that You use accelerometer.

If You need these devices for stability only, then 2-axis is enough, however with 3-axis IMU You could achieve high precision steering as well.

The way You get data from device depends very much on what type of device You have: digital or analog. Digital comms normally use I2C or UART, sometimes PWM; analog devices outputs voltage which is uC has to read using ADC.
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Kristian W

Offline roboninja93Topic starter

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Re: gyro output
« Reply #4 on: January 10, 2012, 12:08:30 PM »
thanks for the reply...
3 axis gyro with 3 axis accelerometer will provide great stability and it will be a bit expensive....
but i want the most cost effective solution (precision is not of prime importance but cost is)
its not a problem to compromise on the stability.. so which is the cheapest alternative to go with?
thanks :) 

Offline newInRobotics

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Re: gyro output
« Reply #5 on: January 10, 2012, 01:32:19 PM »
Accelerometer will probably do, but it will require some heavy noise filtering in software if it's a digital device, if it's an analog one - software and/or hardware filters will have be applied.
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Kristian W

 


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