MrDEB
Well-Known Member
My cheapo brother bought an EAS (electronic article surveillance ) setup from China.
FIRST the directions are broken English
not very descriptive (don't even show how to connect power (bro said it could be connected in 5 different ways?) Probally why it smoked at first try.
He actually got it working but some tags would not set the alarm off.
I wonder if the DVD (video store) is preventing triggering?
I got to wondering how hard would it be to build such a device?
found a schematic but its for a small table top unit (prototype)
Electronic article surveillance
circuit sounds easy enough. A 58KHZ feeding some high end op amps.
looks like the Amtel chip is used for generating the 58khz only.
thinking = build similar but larger amp, connect to two antenans on bought unit?
seeing how there are numerious pots to adjust (no real help in tunning description) I am contemplating using a frequency counter (I need one anyway) then measure the transmitter frequency??
specs as I did some investigating
CTR freq = 8.2mhz
scanning freq = +/- 500khz
scan rate = 180hz
detect spacing = 1.2 to 1.6M
bandwidth = 7.5mhz to 8.5mhz
FIRST the directions are broken English
not very descriptive (don't even show how to connect power (bro said it could be connected in 5 different ways?) Probally why it smoked at first try.
He actually got it working but some tags would not set the alarm off.
I wonder if the DVD (video store) is preventing triggering?
I got to wondering how hard would it be to build such a device?
found a schematic but its for a small table top unit (prototype)
Electronic article surveillance
circuit sounds easy enough. A 58KHZ feeding some high end op amps.
looks like the Amtel chip is used for generating the 58khz only.
thinking = build similar but larger amp, connect to two antenans on bought unit?
seeing how there are numerious pots to adjust (no real help in tunning description) I am contemplating using a frequency counter (I need one anyway) then measure the transmitter frequency??
specs as I did some investigating
CTR freq = 8.2mhz
scanning freq = +/- 500khz
scan rate = 180hz
detect spacing = 1.2 to 1.6M
bandwidth = 7.5mhz to 8.5mhz
