Hello. I am trying to set up a simple alarm system to alert customer that they are still wearing our RFID armbands. These are time keeping armbands for a trampoline park. All it needs to do is sound an alarm and a sign alerting them to return to the front counter. I understand how RFID work, the reader, antenna, etc, but I have never set one up before. I have looked at commercial systems and they will cost more than the wristbands!! I think the M6E paired with the right antenna would be a good direction, but I would like to get some feedback. Read range is 10-20 feet and the wristbands are Class 1 gen2
How do you intend to alert the customer? Are they required to check in (scan their tags) periodically?
This is more accidental walking off/theft prevention of the wristbands. The antennas will be around the exit and my hope was that I could playing a sound or recoding to return to the front desk and a visual indicator - strobe maybe. My hope is that this will be used infrequently as the wristbands are supposed to be removed when they indicate that their jump time is over - they go from blue to red. the wristbands are written to at the front des and they have to be removed with a magnet key.
Thanks for the response
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That shouldn’t too difficult, just have the alarm set so that any tag sets it off and put the antenna by the exit.
You might have a few false positives but those shouldn’t be too hard to deal with.
Gets more difficult if you want to alert on your tags only, you’d need to connect the reader to a database of known tags then but i don’t think you will need to go that far in the near future.
Another option would be to charge a deposit on the arm bands that gets given back when they are returned? Might be more trouble than it’s worth though.
I like the check in/check out system myself, especially since the check out is necessarily taken care of at the desk. We probably can’t hack the wristbands much anyhow, but a strobe or other nuisance would have been kind of neat.
Does the facility offer lockers for shoes and belongings during tramapoline sessions? Maybe that could be the time & place to return wristbands. It worked at the bowling alley.
I think enough time has passed to tell about how … um, some older boys, sixth graders, probably, would cut the security strips off of videos from Blockbuster to use for pranks. You could tape one inside your shirt to trigger the theft alarm at the video store for hilarious laffs as the clerks, barely out of school themselves, fumbled around looking for the stolen item. A really sinister kid might hide one in his sister’s coat. Note that this was a carryover prank from hiding library books (with similar security devices) in classmates’ bookbags, also setting off the alarm but the librarians were wise to the trick.
Yes. The approach of alarm with all rfid tags is what I was going to start with, but I want to make sure that I have the right reader/antenna combo with the ability to connect to a raspberry pi to run the add-one or the database for specific tags. The goal is to have the wristbands removed by the court monitors once they change colors but this would be for the stragglers that they miss.
So the ask is that I need help pair a reader with 1 or 2 antennas with the ability to connect the reader to a control system - arduino or raspberry pi to control sounds and lights.
What is the GPIO of the M7E? It looks like you can set it as input or output and H/L, but I cant tell when the state changes. I would like it to read HIGH when a tag is detected and go LOW when there is not tag. It seems to go high when reading and then stay high. I would like to use this signal to trigger a relay on an arduiino. Any help would be appreciated and thanks in advance.
You can set de GPIO as output or input : SparkFun_Simultaneous_RFID_Tag_Reader_Library/examples/Example9_GPIO/Example9_GPIO.ino at master · sparkfun/SparkFun_Simultaneous_RFID_Tag_Reader_Library · GitHub. They are mend to control an external antenna multiplexer for up to 16 different antennas. But it can be used for other purposes as well.
They work independent of the RFID tag reading / writing circuit. You will have to switch a relay from the program as soon as it finds a (new) tag. Just watch that these GPIO are 3.3v and the 1A that an M7E provides is used for both RFID actions and GPIO control.
Thanks @paulvha. i am trying to figure this M7E out. where would this code go? May be a stupid question, but other than the universal reader that i am currently using, it is nor clear to me how to adjust. I know i am missing something simple, but i havent found it yet. All i want to do is to get a HIGH signal when a tag is read. I can manually do it through IO pin2 when i manually turn it on from the reader. Thanks for your help and this may be a very elementary question 
I don’t know enough about your situation to provide an instant answer. so in order to help :
To which MCU board (Arduino or Raspberry or ?) do you have the M7E connected ?
Which sketch/program do you use ?
I think OP has his reader connected to a PC via USB and isn’t using an arduino.
HAHAH. A little more info would definitely be helpful. sorry about that. I have the rfid reader connected to the arduino through GPIO pin 2. My hope is to have the reader give a HIGH output when a tag is detected and a LOW when no tags are present. I currently have an LED in place on the arduino to detect the high signal. It works when I manually set Pin 2 to HIGH through the universal reader, but as you said paulvha, it is independent of the read state. The hope is that one of the pins on the reader can send the HIGH signal when a tag is read. if this is not possible let me know. I will attach a picture of the current VERY basic setup
This setup will not work… but maybe another is the solution.
Do you know how ArduinoIDE works and to upload code to the board?
If so I can write down how to connect and make a simple sketch to handle what you want.
Yes, i can do the uploads on the arduino and work from the arduino side, but i am more in the dark on the RFID reader side. Thanks for taking the time to do this. I am still learning and this will help. When i read the documentation on the Reader, it seemed straight forward, but i was wrong.
But i did get the arduino to recognize the high and low states from reader (happy about that) but again it was just manually switching it on and off from the universal reader
Hardware
Connect the M7E serial:
M7E-TX → board - D2
M7E-RX → board - D3
M7E-GND-> board - GND
M7E-VCC-> board - 5V
Set M7E switch to SER
connect the board with USB to the PC
keep the LED connected to D9
Optional connect switch between GND and D8
compile sketch and upload
Around line 45 in the sketch you can define :
REPLAY_PIN : pin where the relay or LED is connected
OPEN_SECONDS : the number of seconds the relay / led needs to be ON
DISPLAY_TAG : the default sketch can display TAG info. You can disable
MANUAL_PIN : pin to connect a switch to manually trigger the relay
High level working
When a tag is detected (line 112) StartRelay is set.
If the optional manual switch was pressed, at line 172, StartRelay is set.
At line 176: if StartRelay is set, it will trigger the relay to be set only at the first detection.
Around line 187: it will detect whether the relay was set and if so check that it is active for OPEN_SECONDS. if so it will be switched off.
Attached the sketch… but i have not tested…
example1_constant_read_gpio.txt (7.6 KB)
WOW!!! Can i set the RFID to serial in universal reader software?? I will get working on this and let you know. Thanks a ton!!!
No need to URA… no need to set serial… but make sure to download the RIFD library following the M7E hookup guide.