arduino and sensor needed/ will pay

I need a arduino and sensor custom made for my needs. I am a newbie to this and do not have enough expertise to built/program it myself.
I need it programmed so that if a person walks within a 10 yards of a IR sensor, a battery operated object will switch on for a duration of 20 seconds and then turn of.
Can any body make/program an arduino and IR sensor for me?
And what would the fee be? I would need it in 2 weeks
Thanks
Jonny Detiger

/* just a silly example */

#define sensor_pin 5 /* use analog input pin 5 /
#define switch_pin 8 /
use digital I/O pin 8 /
#define sensor_threshold 500 /
just an example */

void setup(void) {
pinMode(sensor_pin,INPUT);
pinMode(switch_pin,OUTPUT);
digitalWrite(switch_pin,LOW);
}

void loop(void) {
if ( analogRead(sensor_pin) > sensor_threshold ) {
digitalWrite(switch_pin,HIGH);
sleep(20000);
}
}

For this to work I suggest you use a transistor connected to the switch_pin driving a relay.
http://www.arduino.cc/playground/Main/InterfacingWithHardware

There’s even a post dealing with this topic:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1241779257

What do you need to Arduino for? Is there more to it than this? Because you can do what you’ve asked for with an IR sensor and a 555 chip.

A trip to the hardware store could build the same thing:
(but it will be more fun with the arduino)


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Anachro, what exactly is a 555 chip?

a 555 chip is a timer chip

jason

The 555 is indeed a timer chip:

It’s probably the most widely used chip ever made, and was in the Top 25 Chips list published recently.

http://www.doctronics.co.uk/555.htm

EDIT: Another 555 web page with good info:

http://www.kpsec.freeuk.com/555timer.htm

Thanks for all your input. I have worked with the off the shelf hardware before as suggested, but I had some problem with controlling the timer and sensitivity of the sensor and it was basically on all the time. Also I do not have a power source and want to do this all by a battery operated device.

I really like the idea of the 555 timer chip, I will look into that. I am just wondering if somebody would help me build it as I am new to this and would need this to be 100% reliable. (willing to pay fee)

Thanks
Jonny

would need this to be 100% reliable. (willing to pay fee)

No matter what fee you pay this will not be 100% reliable nothing in the world is and that includes electronics. It’s my day job to make things as close to 100% as possible but you can only ever get to about 99%.

99% sounds good.