I'm a web developer by profession and as a hobby project would like to develop a simple people counter which doesn't need to be fully automated.
What I vision:
A device (RF module?) with a unique ID/signature
Carryable by a person in hand - not secured to a fixed spot.
Has add person and subtract person buttons
Emits a radio signal of total count so far when a button is pressed
Signal should be consumed by a device attached to a PC
The PC has an app which aggregate counts from different devices (based on their unique IDs) and does whatever processing like emailing/sms etc (I can do this part).
The devices will be like hand-helds so the person can move around while counting.
Is this possible? Where can I start? What do you think would be the approx. cost of one device with plus, minus, send and reset button?