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Sorry about the limited information.
Since my mother is a teacher, she is always looking for ways to make the classroom more efficient. The idea she had was to have each child wear a wrist strap with some buttons on it. The child would press a button and a bell would ring, along with a LEDs with the childs name on it lighting up..
It would be controlled via netbook and would need something to send a signal to the netbook, and then the netbook would light the appropriate LEDs up, depending on the child.
We would like something that would not need a microcontroller to send the signal, but would have an individual ID.(If we really need a microcontroller we could just outsource some PCB, as she has a limited budget)
Hi,Quote from: Mr. Ninja on July 04, 2012, 08:09:06 PMSorry about the limited information.You still need to tell us about what range you require andwhether it has to work through walls etc.It would need a range of somewhere between 20-30 feet, and it would not have to go through solid walls, but I'm not sure if It will need to go through a small whiteboard (on a metal trolley)Quote from: Mr. Ninja on July 04, 2012, 08:09:06 PMSince my mother is a teacher, she is always looking for ways to make the classroom more efficient. The idea she had was to have each child wear a wrist strap with some buttons on it. The child would press a button and a bell would ring, along with a LEDs with the childs name on it lighting up.. So, she can sleep until required? Quote from: Mr. Ninja on July 04, 2012, 08:09:06 PMIt would be controlled via netbook and would need something to send a signal to the netbook, and then the netbook would light the appropriate LEDs up, depending on the child.I assume that's what you want the Arduino to do??YesQuote from: Mr. Ninja on July 04, 2012, 08:09:06 PMWe would like something that would not need a microcontroller to send the signal, but would have an individual ID.(If we really need a microcontroller we could just outsource some PCB, as she has a limited budget)You could use encoders and a deoder from eg. Holtek, but a small microcontroller would be both cheaper (down to around 30 cents) and way more versatile.Running the transmitter from eg. a CR2032 lithium coin cell, the cell will cost more than a controller.For cheap transmitters (with less range than announced though), try the ISM transmitter/receiver pairs from Seed Studio:http://www.seeedstudio.com/depot/wireless-rfism-c-139_140.html(Perhaps ask them if they're willing to sell say 2 receivers and 30 transmitters (or whatever number you need.One issue that you cannot escape easily, is the situation where two transmitters are on concurrently, but given the short time a transmission takes, it shouldn't be too bad (although an "acknowledged" LED or similar to tell the student that the keypress is received would be helpful).Which one are you talking about? I'm not sure
Edit: For the recievers transmitters you meant either of these two [...] right?
_____| |_|_|_|__|__|_|__|_| AGC 0 0 0 1 1 0 1 0Sending the 8 bit word 2 or 3 times consecutive allows for comparing the received bytes to discardany transmission where they don't add up. Repeating the byte 3 times would then look like this: ____ 0 0 0 1 1 0 1 0_| |_|_|_|__|__|_|__|_|_|_|_|__|__|_|__|_|_|_|_|__|__|_|__|_| AGC 0 0 0 1 1 0 1 0 0 0 0 1 1 0 1 0