I'm hoping to make a small object the size of a AA battery or slightly larger. It will be powered by a AA battery if I can get a clean and cheap boost regulator worked out, otherwise 2 AAA. It will pulse a red or green LED at slow intervals (.5s pulse once per 20 sec at first, speeding up to 1hz after several min (5 min?) then after several min more going to constant on). It will contain a PIC 12F509 mcu or similar that will spend most of it's time in deep sleep mode.Bigglez wrote: How big is the object?
Is the object battery powered?
How long does the object stay alive?
Is this a contact or a proximity detector?
How close does the object have to be to the proximity detector for detection?
What happens if two (or more) objects arrive at the detector?
How long does the detector have to identify the object?
Is the object tamperproof?
What is the cost budget for an object?
What is the cost budget for a detector?
A little more info from you would narrow the choices and set
the performance for a reliable solution (on a given budget).
Once the device is located it will be taken to a base station of either team A or team B where it will be "rescued". It will be placed in/on/near the base station. If the taken to team A's base station will light solid green, if taken to B's base station light solid red.
The kids will be in a rush to rescue all the objects and get as many as possible to the base station. Therefore the process of "rescuing" the device should be simple. It could be anything, maybe touching the device to the base station or getting it to within a foot of the base station, or maybe the base station is a box and they just toss it in there.
RFID sounds cool except it all sounds a lot more complex than I'd intended. The idea of being able to detect a polarized magnet is may be a better option because there need not be any exposed contacts and just touching it to the surface of the station will suit the need.
If I could get the cost per device without the battery to $2 - $3 it would be a awesome. The PIC 12F509 is about $0.75, I already have scads of LEDs, resistors and capacitors. I think I need an inductor and a FET to boost the voltage from an AA up to the needed voltage for the pic/led (been a while since I've done it so need to refresh my memory on that part) but those aren't expensive at all. The base station can be more expensive but will love to do it as inexpensively as possible.