Electronics help plz

Appelhanns · 2 Feb 2009 at 15:43

Ok then, I've done a bit of research but cant find much.

Basically...is it possible for me to mock up a little circuitboard with an inertia switch/sensor that will illuminate an increased number of leds as the G's increase?

Any guides or books I could read into how to wire it all up would be great?

Thanks guys

SourChipmunk · 2 Feb 2009 at 15:52

http://www.analog.com/en/mems-and-sensors/imems-accelerometers/adxl320/products/product.html

edit: I can't view this video from work. Is this what you're looking for?

Appelhanns · 2 Feb 2009 at 16:03

That's helpful thanks dude.

HummuH1 · 2 Feb 2009 at 16:18

Yes, yes you can. Good luck.

Are you building a spaceship?

I built one once. It was rubbish.

GeForce · 2 Feb 2009 at 16:30

How many dimensions do you want to measure in? And do you want to show the sum of g's, or the number of g's per axis?

Either way, an accelerometer + ADC + microcontroller + shift register is probably your best bet.

Appelhanns · 2 Feb 2009 at 16:31

HummuH1 said:
Yes, yes you can. Good luck.

Are you building a spaceship?

I built one once. It was rubbish.

How did you know??? Wanna help?

Ok, so it looks like i just need the same stuff as a g meter but how can i display the output as bar graph as it were?

Also, anyone know where i can get a single axis accelerometer and do i need digital or analogue output?? thanks

edit:ADC = analogue to digital converter??

p4radox · 2 Feb 2009 at 16:44

GeForce said:
Either way, an accelerometer + ADC + microcontroller + shift register is probably your best bet.

That sounds like a decent option.

You might also consider doing it with a load of comparators of varying thresholds and feed in an amplified signal from the accelerometer.

SourChipmunk · 2 Feb 2009 at 16:44

I was hoping the link to the video I gave you had those answers. Sorry.

This is the link I pulled it from:

http://www.embedds.com/diy-personal-g-force-meter/

Appelhanns · 2 Feb 2009 at 16:55

p4radox said:
That sounds like a decent option.

You might also consider doing it with a load of comparators of varying thresholds and feed in an amplified signal from the accelerometer.

Being a n00b of this sort of thing, which is going to be easier?

Raist said:
I was hoping the link to the video I gave you had those answers. Sorry.

This is the link I pulled it from:

http://www.embedds.com/diy-personal-g-force-meter/

Cheers dude, seems I have a possible shopping list in there which has helped.

Appelhanns · 2 Feb 2009 at 16:57

could i use this curcuit from the link above...

but display the value in a bar meter type thing?

Thanks for all the help guys

Appelhanns · 2 Feb 2009 at 22:03

Anybodies? pwetty pwease.

geuben · 2 Feb 2009 at 22:07

Yes, and No. You'll have to look at the datasheet for the ADXL and for the PIC, you'll also need a PIC programmer (or build the programming pins into you circuit). You will also have to find a bar meter thingy and figure out how it works and how to incorporate it into the circuit. Finally, you'll have to program the PIC.

Appelhanns · 2 Feb 2009 at 22:51

Not much then!!! Lol cheers

Pinter75 · 2 Feb 2009 at 23:09

You are gonna need an accelerometer, not an inertia switch. That will only do on or off depending on it's angle.

So get an accelerometer: £20 - £30 inc. breakout board.

Now you need a microprocesser - Get an Arduino - ace and easy to program. Get the Freeduino version, it is only £13

Finally, you need an output, you want leds, so get a LED bargraph - £1 - £2

Now for the code.

As the accereometer increases in "acceleration" so does it's output voltage 0-3v. With the Arduino you can read this on an analogue pin.

So, with 3v ref you have 0 - 700 odd incoming to the Arduino.

Set point in the code to trigger an LED at a certain value eg. 10 LED graph = 700/10 = 70.

Xpin = the accelerometer
ledPin1 = 1st on the led graph
ledPin2 = 2nd on the led graph
....

If Xpin > 0 & < 69
{
digitalWrite(ledPin1, HIGH);
}
else if Xpin >70 & < 79
{
digitalWrite(ledPin2, HIGH);
}

So on etc...

http://www.arduino.cc/

Try to avoid PICs as you need burners and what not. I moved away from these and started using the Arduino platform, very flexible and you will also be able to log the acceleration values to SD cards or the serial port.

Appelhanns · 3 Feb 2009 at 01:40

Now thats an answer and a half!!! Cheers dude, exactly what I need and it all looks dead interesting, may have to take up a few more projects like this.

Thanks all.

Pinter75 · 3 Feb 2009 at 02:00

No problem.

There are quite a few examples of using the accelerometer with the arduino, Google is your friend on this one.

As for suppliers (none are OCUK competitors):

http://www.coolcomponents.co.uk/catalog/product_info.php?cPath=36&products_id=95

For the accelerometer.

And

http://www.nuelectronics.com/estore...s_id=1&zenid=c08a64fb237c3e4fb573a492d147dc4c

For the Freeduino (Clone of the original Arduino, and 100% compatable - hey it is open source anyways).

You will need the Arduino IDE software and that is free and based on C. It is easy to learn, and as I said there are tonnes of examples.

Have fun, and post back if you get it working.

:-)

p4radox · 3 Feb 2009 at 08:35

The method being described above will undoubtedly work, but I can't help thinking it can be done much simpler. The PIC approach would be great fun as a learning excercise, however.

Here's how I'd do it:

That's only for 2 LEDs but you simply increase the length of the resistor ladder and add some more op amps. The signal from the accelerometer might need amplifiying too, but that depends on which one you choose.