I am trying to implement a concept for somebody else. 

Basically, I want to create a smart surface. I want to create a surface I can throw one or more tagged objects on that should all be recognized. 

I am unsure how to this and what sensors I should use. I have been thinking about using one of the NFC ICs from NXP. However, designing a circuit board and buying this IC is too expensive for our idea. I'm also unsure of whether the surface area will cause problems, because it'll be quite large (think of a small coffee table). 

I've also been thinking about other ways to recognize objects, but I have not come up with anything yet. I am probably not using the correct term. 

Does anyone know of a type or sensor or technique to implement this? 

Note: I am a computer engineer, not an electrical engineer. I know the basics, but really not much more than that, so I prefer a solution that is available as a simple IC or a complete circuit board with the really complicated things done for me by the experts :) 


Question: WIFI USB adapter not detected
Answer: Check out this tutorial 

I think you need to install the drivers. Since url answers my disappear, here is what it basically says:

Now, plug your USB wifi adapter to one of the ports and issue: lsusb. You should see something along the lines of:

$ lsusb

...
Bus 001 Device 004: ID 0ace:1215 ZyDAS ZD1211B 802.11g
...


Okay, it looks like the chipset we have here is ‘zd1211′ (Have a look at http://wiki.debian.org/WiFi for a list of supported chipsets)

Let’s see if there are any firmware packages we can install to get this up and running:

$ apt-cache search zd1211


zd1211-firmware - Firmware images for the zd1211rw wireless driver

Sweet, let’s install that:

$ sudo apt-get install zd1211-firmware


We should be good to go now. Unplug the adapter, plug it back in again and have a look at the output of lsmod:

$ lsmod

Module   Size   Used by
arc      4764   2
zd1211rw 40444  0
mac80211 171628 1 zd1211rw
cfg80211 123084 2 zd1211rw,mac80211
fuse     49036  1


You should see mention of zd1211.

dmesg should also give you an indication whether things are loaded or not:

    $ dmesg

...
usb 1-1.2: new high speed USB device number 4 using dwc_otg
usb 1-1.2: New USB device found, idVendor=0ace, idProduct=1215
usb 1-1.2: New USB device strings: Mfr=16, Product=32, SerialNumber=0
usb 1-1.2: Product: USB2.0 WLAN
usb 1-1.2: Manufacturer: ZyDAS
cfg80211: Calling CRDA to update world regulatory domain
usb 1-1.2: reset high speed USB device number 4 using dwc_otg
ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
zd1211rw 1-1.2:1.0: phy0
usbcore: registered new interface driver zd1211rw
zd1211rw 1-1.2:1.0: firmware version 4725
zd1211rw 1-1.2:1.0: zd1211b chip 0ace:1215 v4810 high 00-1a-ee UW2453_RF pa0 -7---
...


Awesome, looks like the adapter is up and running! To see which networks are available, do:

$ iwlist wlan0 scan


…which should give you a list of wireless networks around you.

Good luck