noob: low cost send/receive with PC as final aggregator

Question

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?

Answer 1

I would suggest using an XBee 802.15.4 development kit. This way you can use the Push buttons found on the development board for your inputs and the matching interface board and associated RF Module on the PC side to collect the DIO data with using our API interface option. For more info on that, I would suggest looking at http://www.digi.com/support/kbase/kbaseresultdetl?id=2188

Kit XB24-DKS located at http://www.digi.com/products/wireless-wired-embedded-solutions/zigbee-rf-modules/point-multipoint-rfmodules/xbee-series1-module#models

Comments

Also, note that the XBee would send the data samples, but it's the consumer who has to keep the count of objects (add one for every time "+" button is pressed and subtract one every time "-" button is pressed)

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Yes I know that.  The XBee 802.15.4 modules have an API output frame that you can enable that would allow your application running on a PC or Processor to keep track of the button bushes.