# Building accelerometer

#### WhiteLionV

Joined Oct 22, 2006
2
Hi:

Im a (desperate) electonics student looking for help to build a "simple" device capable of measuring the acceleration of an object. I have nearly no limitations, just one, money; and because of this Ive come to you.

What needs to be done is the following:

1. Get the speed of the object at 1 point
2. Get the speed of the object at an other point.
3. calculate: (speed2 - speed1) / total_time.
4. Display result.

HTML:
t1                  t2
[===========object==========>]
|    |              |    |
s1   s2             s3   s4

---D1---            ---D2---
1. Collecting data (Easy part):

- The object hits/pass the first sensor/switch [s1]... 2 timers starts [t1] [t3].
- The object hits/pass the second sensor/switch [s2]... the timer stops [t1].
- The object hit/pass a third sensor/switch [s3]... timer starts [t2].
- The object hit/pass the fourth sensor/switch [s4]... 2 the timers stops[t2] [t3].

-?- I belive both times must be recorded, saved or something so we can use them later.

2. Calculating (The other part):

- Calculate speed1 = D1 / t1 //D1 & D2 are constants.
- Calculate speed2 = D2 / t2
- Calculate accel = (speed2 - speed1) / t3
- Display result

And thats it...

I found some related proyects and information on the internet but the problem is they are too expensive, and if they are not, i cant figure out how to bring all the stuff I need together.

If you have any ideas of how to do this, or other way to achieve my goal (calculating the acceleration) I will be deeply thankfull.

Im beging, Im clueless and Im ignorant... I want to learn, Im not afraid of any idea I just need some guidance...

Thank you

By the way sorry for the large post and the crappy english

#### WhiteLionV

Joined Oct 22, 2006
2
I have already build my "emergency exit" to this asigment which is a device that capture data exactly the way described above BUT, this data is sent into a computer where the timer and the calculations are being held...

This is it... beautiful isnt it?

You can see the LPT port, leds (LPT output), buttons (LPT input), and the switches (Input)

Those are the swithes... the object hits the wire and the circuit sends a signal to the computer where all the process begin... 4 switches, 3 timers, 2 speeds = 1 acceleration...

Anyway this is just Plan B, it may give me a good grade but i really want to make this with out a $1000 cpu... the due date is November 19, I think it can be done... but I really need your help... Thanks again P.S. If someone needs help making a circuit interact with a computer just mail me (fran_c77@hotmail.com) thats something I know how to do. Although probably anyone here know a lot more about that... but anyway, if there is something I can help with... #### beenthere Joined Apr 20, 2004 15,819 Hi, Look into Analog Devices and their iMEMS line of accelerometers. The price range from Digi-Key is from$8.50 to \$23.00.

They will take more time to understand before using, but will need less construction to use.