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286  Forum 2005-2010 (read only) / Frequently-Asked Questions / one general question concerning RFID readers... on: April 07, 2006, 08:33:08 am
maybe there are differences between different RFID readers, but i've been wondering what they report if there are several RFID tags in reach. do the tags interfere -> aren't readable , or is it possible to distinguish between them and read them one after the other?

in case there are differences between readers: i mean those that have been successfully used with arduino :-)

best, kuk
287  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: a newbie would like to use a servo on: April 09, 2006, 06:47:32 am

(just take the wiring from wiring and the code from arduino)

as i understand, a standard servo motor has three pins.

-> Vdd (power)
-> Ground
-> control pulse

the easiest way (READ THE NOTE AT THE END) would be to connect Vdd to 5V out on arduino and ground to ground. (assuming that your servo is ok with 5V. check the manual! )

-> now your servo gets power but will not move yet. you will have to send "pulses" to it, which tell motor in which direction it should move.

so the third pin (control pulses) from your servo goes to a digital out of your arduino. lets call it servoPin, like in the code.

a pulse means a signal which is determined by its length. between pulses there is a small pause (20ms in the code example).

let's say pulses(power HIGH) are dashes (-) and pauses(power LOW) are dots(.):

if you pulse .-.-.-.-.-.-.-.-.-.- your servo motor will move to the left.

if you pulse  .----.----.----.----.----.----. on servoPin your motor will turn to the right.

if you pulse  .----.----.----.-.-.-.-.-.-.-. your servo will first move to right and then to left.

it's a quite simple concept: short pulse->left , long pulse->right

the exact timing depends on your servo.


motors tend to draw a lot of current just before starting to move. YOU SHOULD NOT take the Power directly from arduino, since this behaviour could interfere with the internal computing on your board.
you can do so for testing purposes on your own risk as i don't think that this could do much harm to the board. you just can't be sure that it will work properly.

if you're taking power from an external source, just make sure that both grounds (arduino and external source) are both connected to your motor.

and as always: someone please correct me if i'm wrong :-)

best, kuk

288  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Rx/Tx pins on: March 30, 2006, 07:23:39 am

for rx and tx you don't need to bypass anything as far as i can tell. as Mellis said, digital pin 0 and 1 are marked rx and tx. all data you send through the serial interface does flow through your usb-port to your computer and at the same time through the tx-pin. incoming data is read both from the usb port (coming from your computer) or the rx-pin on arduino.

this should be true as long as you don't assign any other function (digital in or out) to those pins.

as for RTS and CTS (ready-to-send/clear-to send) on your bluetooth module you can just connect them to each other i guess. those lines are used for flow control, i.e. to signalize that a device is ready to send or receive data. if you experience problems you might bypass/grab those line from somewhere on the board. maybe someone more familiar with the board will help you then.

see  >>>"flow control" for more info.

AND someone correct me if i'm wrong please!

please post your results here! i'm thinking of going bluetooth too.

k u k
289  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Bluetooth on: March 25, 2006, 10:44:43 am
i don't know anything. but i guess someone will post it in the news if BT boards are ready.

in the meantime... i wonder if anyone had success using available bluetoothmodule on a separate shield. there seem to be quite a few cheap BT modules. ROK-101008 from ericsson features an UART interface.

anyone knows what one could expect trying them? they even support streaming audio both way. if one could control this with arduino i imagine great "standalone" (no wires) projects.

come on you more skilled!

290  Forum 2005-2010 (read only) / Bar Sport / Re: Just to say Hi! on: January 12, 2008, 11:48:17 am
I you have a wife, girlfriend, kids, relatives, friends, kiss them godbye, from now on you will never have any time left for them :-)
not so fast. i found they're quite useful to get your projects and ideas sorted. plus they can be used to just babble at them what you've just learned. they're very forgiving.

last but not least, birthdays, christmas and that such are wonderful occasions to actuallay use them phase one prototypes and legitimate the 500 LEDs bargain from ebay.

i'm a family guy i guess.

PS: welcome, maverick.
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