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IMU pins help

xxJaRxx

Oct 16, 2011
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Oct 16, 2011
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I have just bought and received an analogue IMU for a project I'm working on but I am slightly confused with a couple of the pins, I'm hoping someone can help me out (pictures attached).

X-Acc - X rate analogue output of the accelerometer.
Y-Acc - Y rate analogue output of the accelerometer.
Z-Acc - Z rate analogue output of the accelerometer.
ST - No idea???
VRef - Reference voltage? So if I fed it 5v would all my outputs be an analogue voltage from 0-5v? It mentions a 2.8v VRef on the second picture..
Y-Rate - Y rate analogue output of the gyro.
X-Rate - X rate analogue output of the gyro.
GND - Ground.
RAW - Is this the raw input voltage to the regulator (in my case 5v)? It mentions 3.3v on RAW input in the second picture..

X4.5 - No idea???
Y4.5 - No idea???
PTATS - No idea???
AZ - No idea???

All responses are much appreciated.

James
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
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It's open hardware. You should be able to find the full specs somewhere.

If you have an image of the other side that shows the chip that is being used then you can almost certainly google for it and get all the information your heart desires.
 

xxJaRxx

Oct 16, 2011
34
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Oct 16, 2011
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Hi Steve,

I've googled for it already and can't find anything about connecting it up.

This is the link to where I got it: http://www.hobbytronics.co.uk/sensors/imu/imu-5dof-adxl335-idg500

It has the datasheets for the gyro and accelerometer on there but seeing as Sparkfun originally put the board together, they wont help me too much for the questions regarding the pins above.

James
 

BobK

Jan 5, 2010
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7,682
Yes, it will. Look at the schematic and it shows what each of the pins is connected to. RAW is the input power. The other pins are all connected to pins on one of the two chips with the same designation.

Bob
 

xxJaRxx

Oct 16, 2011
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Oct 16, 2011
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Ah okay cheers Bob, I'll get on that tonight and see if I can line them up.

James
 

xxJaRxx

Oct 16, 2011
34
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Oct 16, 2011
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34
Okay so I have looked over the datasheets now and I'm fairly confident I know which pins I need to use and what they do, apart from the VRef pin. It seems that only the gyroscope (IDG-500) has a VRef input and the accelerometer (ADXL335) is fixed.

Can someone explain how I can figure out what analogue voltage range I will receive from the output of the gyroscope and the accelerometer? And also how VRef affects the gyroscope?

Cheers
James
 
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