Another "Which board should I buy!?" thread

Just a bit confused about all the different kinds of board.
I’ll mostly be working on haptic stuff. So very simple processing of some input, have this activate a motor, etc.
Would the lilypad be suitable for this? Any disadvantages to this? Can it deal with multiple unrelated inputs and outputs?
Thanks a lot.

Haptic alone, unfortunately doesn't say much, you may be able to use the simplest board, but perhaps you'll need a lot more.

What exactly would you like to sensor, what precision do you need, how many sensors will you need, which kind of sensors would you like to use, which frequency of measuring do you need ?

I do not have much experience with haptic sensors, but If you describe the project/goals you have in mind, it will probably easier to get answers.

This needs to be wearable, preferably strapped to my leg most of the time. It needs to be fairly discreet. My general idea is some kind of electronic compass, which causes a small (hopefully less than 3cm) motor to vibrate, with the frequency related to the direction in which I'm facing.

Another one requires some kind of magnometer, again causing a motor to vibrate with the frequncy related to the magnitude. Magnometer needs to be small, strapped to a hand or preferably a finger.

My third project requires an LED that blinks in unison with a vibrating motor. It would be better if the motor for this were smaller, 0.5cm would probably do. The pattern of activity can either be controlled by a computer or predetermined, whichever is easier.

Any advice on parts would be very greatfully received. Could two or three be done using the same board, or would one for each be needed? Thanks a lot.

zokvok: Any advice on parts would be very greatfully received.

I've just had great fun ripping the tiny little vibration motors out of a stack of BlackBerry devices we had here at work. They are truly small, about 4mm square in the cross-section, and maybe 1cm long. They also come with an of-centre-weighted wheel on them to vibrate. So find some old phones and steal the vibrators out of them!

Unfortunately I also have no building experience with electronic compasses/magnetometers. :wink:

I probably could wear any arduino in long trousers without people noticing. Length and width
won’t be a problem, the flatter the board is, the better it is to hide though.
Lilypad’s quite flat.
(It may be wise to cover the on-board power&blink leds before people start asking ;))

After reading a little about magnetometer/compass-chips I guess it’s possible to use just
one arduino for all applications you have in mind, any type would do. The size of sensors &
vibrator-motors also look promising. Motors are available quite cheap as replacement-parts
as well. Motors often require more power as an arduino-pin can handle though, even very small
ones. You may need 3-4 small cheap extra components per motor to drive one without ruining
components.

There’s a difference between looking promising and being the right choice though,
I only glanced at two data sheets and read a few pages in forums after googling
“Arduino Magnetometer”. Strapped to your finger I’d guess tilting may cause a lot of problems
for example. Hopefully others with more experience will be able to tell you a lot
more.

A predetermined pattern of activity or one controlled by computer… both are possible.
With a little luck you’ll be able to store all patterns in arduinos flash or EEPROM but I don’t
know the amount of data needed for patterns. If too large, you may need a small extra
memory chip or SD-card solution if the set of patters is extremely huge.

Being strapped to your leg and controlled by computer you may want a wireless solution
which is possible with a small, hide-able module as well.

Motors and Leds are relative easy to programm in the arduino-IDE. Communicating with/interpreting
data of a compass/magnometerboard may take a box of aspirins before you got them working
the way you like though. It may be wise to spend time (re-)searching one best supported by
Arduino-users. I expect you’ll find a lot of experience on sites/forums about model air planes
& robots, hobbies where arduino is used a lot as well.

Size probably won’t be a problem, the Lilypad + extra parts would be fine.
If you want to you could add other functions like for example GPS as well.

I’d probably post a magnetometer-question in sensors, tell what you would like to do and ask
about the possibility of using magnetometers.

P.S. keep in mind not all arduino’s have an USB-port to upload a program, You’ll need
an USB-breakoutboard for a Lilypad and a number of other arduinos.