The right sensor to measure acceleration?

ild put a one direction accelerometer and mesure the average movement, this will be the acceleration

I'd probably stick the main circuit board (the heavy stuff) right in the middle, then put a little accelerometer on the edge. Do consider the weight of the whole thing though, if it's too heavy/not balanced it might not fly well

Most accelerometers are tiny surface mount components though, are you going to get a PCB made, or is it going to be on perfboard? I would personally suggest designing a PCB on eagle or something and getting it manufactured (not that expensive, depending on where you send it). That way you can use a tiny surface mount accelerometer and make the design as small as possible.

Deducing how fast the frisbee is moving across the ground by measuring acceleration will be very difficult becasue the frisbee is spinning and because it experiences a very high acceleration when you throw it followed by decelleration at  amuch lower rate as it travels. This would mean the you would need an accelerometer with a large dynamic range and very good linearity.

Calculating the angular velocity by measuring the centripetal acceleration with an accelerometer would be much easier. http://en.wikipedia.org/wiki/Centripetal_force

If you put the accelerometer in right distance from the centre you may be able to make the centripetal acceleration comparable with the linear deceleration of the whole frisbee due to air resistance and then you might be able to separate the two components of acceleration. You would need to use two accelerometers diametrically opposite each other, both would always see the same centripetal acceleration but the linear deceleration would result in a sinusoidal signal (frequency equal to frisbee spin rate,  amplitude proprtional to linear acceeleration or decelleration) superimposed on the steady (ish) centripetal acceleration signal.

You can do some sums based on the Wiki article and perhaps some frisbee tests to work out where to put the accelerometer(s) and the range of accelerations you will see.

Analog devices sell several  suitable surface mount parts. ADXL335 might do you, it's a 3 axis part but you still need two because they need to be in two different places in the frisbee (unless you just estimate angular velocity). You might find the package and operating voltage challenging.

MK

I believe that a Gyro sensor would be definitly better to measure the rotation of a frisbee than an accelerometer but it is much more expensive

If cost is a constraint (you never know, may be your luminous frisbee will be the toy of the summer 2013 and be sold millions units), I would recommend to consider Freescale MMAxxxx or ST LIS3xxxx accelerometer, which are cheaper

May be you could start prototyping just with the Freescale ZSTAR3 reference design demonstrating Freescale accelerometers, Zigbee radio solutions and 8-bit S08 MCU family.

This demo is based on two boards :

- a standalone battery powered board featuring the accelerometer and a System on Chip embedding the radio transceiver and an 8-bit MCU from the Freescale S08 family (MC13213) that you could stick on the frisbee to measure the acceleration

- an USB dongle featuring a radio transceiver (MC13191) and an 8-bit MCU embedding an USB device controller (MC9S08JW).

Sensor board is available in two versions : based on a digital accelerometer MMA7455 or based on an analog accelerometer MMA7660 (higher bandwith but need a good ADC in the mcu) ?

Sensor board RD3172MMA7455LRD3172MMA7455L is sold in Farnell store and costs less than 40£

Another alternative could be to acquire a Freescale Freedom board based on a newer MCU from the Kinetis family (ARM Cortex-M core) as they all embeds the digital accelerometer Freescale MMA8455.

I would recommend you the FRDM-KL05ZFRDM-KL05Z sold down to 8£ by Farnell UK, which is based on a small Kinetis-L mcu (ARM Cortex-M0+) : the MKL05Z32VFM4 with 32KB of flash in QFN32 package.

Every Freedom boards (FRDM-KL25Z, FRDM-KL05Z, FRDM-K20D50M) embeds an innovative multimode debugger (OpenSDA) so you don't need to invest in an expensive probe to program, debug your project.

Freescale Codewarrior is a free developpement suite for Freescale MCUs and the Special edition allow you to compile for free up to 64KB of code for a Kinetis-L (ARM Cortex-M0+) target and 128KB of code for a Kinetis-K (ARM Cortex-M4) target. Processor Expert (included in Codewarrior) might be very helpfull if you are not familiar with Freescale MCUs or development tool. It is a code generator tool with prebuild components.

Every Freedom boards are compatible with Arduino shields so you could simply associate it with a LED driver Arduino shield like in the following demo based on a HL1606 driver chip found HERE

If you are interested in more information concerning the Freedom development platform, looking for tutorials or project examples (like how program the Kinetis-L05 to drive an RGB LED based on the Accelerometer measurements), I would definitly recommend you this dedicated section in the Knode

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RE: The right sensor to measure acceleration?

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