Hello,
I'm trying to convert an accelerometers raw output into gs.(1) Does anyone know how to do this as simple as possible?(2) Once i get this value I need to be able to print it to the Serial Monitor. I've tried a few times to print the float but it wont print the decimal places? has anyone run into the same problem as me and found a soloution?
maybe this will help:
http://rubenlaguna.com/wp/2008/11/03/arduino-tilt-sensor-using-mma7260q/
You need find out what the sensitivity of the accelerometer is from the datasheet.
This is normally expressed in units like "mV/g" for analogue devices, or "counts/g" for digital ones.
Conversion is simple arithmetic, and can be verified by using the acceleration due to gravity.
If you use Arduino 0018, you can specify as many decimal places as you think sensible.
Otherwise, use fixed-point and scale your output by the appropriate power of ten.
Accelerometer:
300mV/g
now how would I implement the two, Its all very confusing.
Let's assume your analogue reference is 5V, so 5 / 1023 is about 4.88mV.
Each increment of one from your analogRead represents about 4mV (you can do your own arithmetic).
So, 300mV/g means for every 300mV you read, that means 1g of acceleration.
0.300 / (5/ 1023) = 61.38.
You'll probably find your 0g point is about halfway from 0 to 5V, so an "analogRead" of about 511.
So 1g will read either 511 + 61, or 511 - 61, depending on the orientation of your accelerometer.
Well I dont think that its 61 gs. how do i find gs. And do you have any comment about the serial monitor?
sorry im a noob.
Well I dont think that its 61 gs
I haven't got a clue what you're on about.
Why don't you post your sketch and circuit - you haven't even said which accelerometer you're using?
BTW, g is measured in ms-2, so "gs" is ms-1, which is a velocity, not an acceleration.
Accelerometer:
Gyro:
Accelerometer pinout:
Accel Arduino
VCC------------> 5v
GND------------>GND
X---------------> 0
Y---------------> 1
Z---------------> 2
Gyro Arduino
VCC-------------> 5v
GND------------->GND
RATE------------> 3
Thats how I have my accelerometer and gyro attached to my arduino. Now the reason i have both these attached is I want to make an IMU with these two sensors to reduce the accelerometers noise(ie: motor vibration). The part I'm having trouble with is combining the two sensors. I've been looking all over the internet with no avail.
Why are you powering the accelerometer from the 5V?
You still haven't posted your sketch.
[edit]Hey - how did "caseygross" know the spec of your accelerometer?[/edit]
casey is my brother..., srry didnt mean 5v. I dont have a code yet because i dont know how to implement the two sensors together yet thats what im wondering how to do.
I've tried a few times to print the float but it wont print the decimal places?
So, you must have some sort of sketch.
Why don't you post it?
i dont know how to implement the two sensors together
What does this mean?
The sensors have already been implemented - that was the really hard part.
All I need is for you to tell me how to combine the sensor readings from the accelerometer and the gyro into an output that doesnt have as much noise from the motors on a heli...
Well, that's going to be hard, because I don't know the spectrum of the noise from the motor(s) on your helicopter, so I can't know what the best noise reduction algorithm would be.
That's the bit you have to do.
Isn't it interesting how a thread that started off talking about 20 lines of C to print a value to the serial monitor becomes a serious bit of real-time DSP?
I think that's what's called "scope-creep".
well can we just smooth the accelerometers readings with the gyro.