Not sure what I need to interface with a Raspberry Pi

Sensors NFC & RFID
1

I’ve been researching RFID receivers and I’ve become interested in the Spark Fun receiver, since it has a much longer range than others. I have a sort of cable car / trolley that I’m building. Here’s a video

https://www.youtube.com/watch?v=EBIFFykNipA

It’s going to be controlled using a Raspberry Pi and a Python script. I would like to place RFID tags along the wire, so the program can tell where it is.

It uses a e-bike motor and battery and can go about 15-20mph when at full throttle. So I need an RFID receiver with good range/reception.

Anyways, if I were to use the Spark Fun receiver, I’m confused about how I would get the tag values into my Python program on the Raspberry Pi. Would I need to run an Arduino or is there a way to just read them on the Pi using a serial port or something? I really don’t need to write to the tags. Just read the number.

Thanks

Michael

2

How many tags will you need over however much distance?

You could use our simultaneous RFID reader (https://www.sparkfun.com/products/14066) to read multiple tags at a time or you could use smaller tags with our other readers (https://www.sparkfun.com/categories/556). You’re largest issue will be synchronizing the tag read time.

I would suggest maybe looking into a rotary encoder or hall effect sensor so you determine how far your motor has rotated and that will be more accurate.

3

The wire is going to be about 300ft long. I want to put a tag near each end to tell it to stop and maybe a couple in the middle. I’ve looked at a few RFID readers online and they don’t have very good range. I’m worried about it going too fast and missing the tag. I guess the Spark Fun simultaneous model is probably what I need. I guess I’ll try to read up more on it. Still trying to figure out how once it reads the tag you get it into the Raspberry Pi and the Python script.

4

I guess I should probably have some kind of backup kill switch too in case it doesn’t read the RFID for some reason.

5

You could also try bumper switches with a separate circuit that the trolly could bump as it goes along. 3-D printers use these to zero out their positions.