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Can someone please help me how to make a circuit layout for a passive RFID tag with an antenna similar to what's in the picture ?
If possible, I would like the circuit to light an LED when close to something emitting a blue tooth signal, or if not that, have it be activated by something easily available/ smaller than a phone, and not a battery that is in contact with the circuit.
If you have ideas or need clarifaction, or can point me in a direction, anything would be helpful. I am looking also for how to determine specific numbers like the capacitance of a capacitor, type of LED, resistance. etc.
Thanks in advance!
I took that picture. I plan on making the antenna with a process called laser direct structuring. Essentially, I can make the loops as thin as .006 inches wide, with a thickness of 300 micro inches. The substrate is 2 inches by 3 inches so, potentially I could fit up to 60 loops.
I can calculate the magnetic field produced by a system with those known parameters if a direct current goes through it, but I am struggling to figure out how a received magnetic field* translates to an induced current. I just want to put it next to something and have and led light up for proof of concept.
Can I make circuit for a passive RFID that will light an LED if you hold it to phone sending out a Bluetooth?
3 Answers
- ?Lv 76 years ago
If you want to detect a slave Bluetooth device, like headphones, speakers, some mice or keyboards or other devices, you need a master Bluetooth device like the HC-05 (a few dollars on ebay) and an Arduino micro controller to read the slave response to inquiry (AT+INQ). This yields the unique MAC address of the slave Bluetooth device, and the Arduino could be programmed to light an led if the MAC address request returns a valid response. You could also store the MAC address for data time comparison, as is done with commercial Bluetooth readers like BlueToad where a vehicle's speed is implied via several monitors a known distance apart on a roadway.
Source(s): https://www.youtube.com/watch?v=7gM-xv4yRZA http://www.libelium.com/vehicle_traffic_monitoring... http://www.columbian.com/news/2013/oct/21/bluetoot... http://www.trafficcast.com/products/view/blue-toad... - ?Lv 76 years ago
A passive RFID makes only enough power to return an RF signal of the ID and it takes its power from the strong nearby reading signal - a few feet or less. It does not come close to generating enough power to light an LED and a Bluetooth signal is not nearly strong enough to create the energy to send back and you don't have the receiver for the RF signal.
