Accelerometer question and help needed !

Other Hardware Sensors
1

hello Everyone,
hope you had a good weekend

what i need to know first is : Can an accelerometer be used to make a Speedometer ?

second: i have this module Accelerometer, Gyroscope, ... Sensor

on its package it says : Accelerometer + Gyroscope + Pressure + Magnetometer

so i need some help please to know how can i work with this ? where should i look ?
it doesn't have any datasheet in the link, but it has a folder which contains files and it says software in the download section

on the other hand, this accelerometer alone has a datasheet but between my hands i have the one above

and what does a magnetometer here do ?

thanks to all in advance

3

That is the popular MPU-6050 sensor. Google "arduino mpu-6050" for lots of project examples and applications. Agreed, it won't work as a speedometer.

4

Delta_G:
In theory the first integral of acceleration is speed so it should work.

In practice an accelerometer makes a really really really shitty speedometer because it relies on already knowing the speed at the outset and any errors get magnified the longer you go.

Magnetometer measures magnetic fields. I'm guessing it is there to use as a compass.

What do you want to measure the speed of? A GPS module is often handy if you can't use some sort of wheel sensor to measure rotations or something.

it's an RC car that i am trying to make a speedometer for it

about the math behind the speed from acceleration well i know how to do that, but in practice you do not suggest I use accelerometer to find the speed of the car ?

5

jremington:
That is the popular MPU-6050 sensor. Google "arduino mpu-6050" for lots of project examples and applications. Agreed, it won't work as a speedometer.

jremington, i checked your suggestion then i looked closer on the module i have, it is different, the name written with silkscreen on the module board is GY-85 and the one written on the package is : 412 ARDUINO 9DOF SENSOR MODULE, and by checking it's components, mine has 2 big chips, 1 medium and like the mpu6050 which has 1 big chip and different pin names so what do you think ?
or it can be programmed the same way as the mpu6050 ?

and for what application can an accelerometer be used exactly if not to measure speed ?! :expressionless:

6

You do need to figure out what device you have, and download the correct data sheet(s).

Accelerometers are used to measure acceleration.

Try your method to create a speedometer, and then you will understand the problem.

7

jremington:
You do need to figure out what device you have, and download the correct data sheet(s).

Accelerometers are used to measure acceleration.

Try your method to create a speedometer, and then you will understand the problem.

there is no datasheet on the website i shared in the main post, however they have a .rar file that contains scripts and example :confused:

this is the exact one i have

8

The accelerometer is the ADXL345. Very popular with Arduino users.

9

Remember that you're trying to measure the speed of a fly while it's flying inside a dragster car that's doing a 9-second pass down the quarter mile.

That's the equivalent of 1G Earth gravity.

10

MorganS:
Remember that you're trying to measure the speed of a fly while it's flying inside a dragster car that's doing a 9-second pass down the quarter mile.

That's the equivalent of 1G Earth gravity.

ok so the final answer is no it can't be for a speedometer, which i have to go back to the hall effect sensor but this accelerometer with the gyroscope can be used to make an autopilot quadcopter for example

thanks everyone for your replies