Hello, I am trying to make a tracker that will track two people in a 14m line in relation to a dolly that is on a track. the goal being to move the dolly to be in the center of the two people. I only need to track the people on one axis. I was considering using rfid but I am not sure how to approach it. I am looking for any guidance you may be able to offer I am on a bit of a tight budget (I am 14 years old without a real paycheck)
thank you
tai
I didn't think RFID went out to 7m.
Can you live with 5.5m?
https://www.parallax.com/product/28999
not really I am a fencer attempting to build a dolly that will track the fencers and then attach a camera (maybe a smartphone) and use it for video review.
RFID will only tell you that some tag is within range, no more. It will not tell you how far it is away nor In what direction it is.
However if you are a fencer then CrossRoads is your man.
if rfid won't work what do you you think will any ideas?
do you you think will
The problem is a lot harder than you think. Many people ask, there are lots of fancy answers but no practical / affordable solution has been made as far as I can tell.
Fencers are generally not 14 meters apart -that would require each fencer standing at the opposite ends of the strip. The en garde lines are only 4 meter apart to start, and the fencing is usually done closer than that.
I would think the dolly would only have to go warning line to warning at the extreme, so 5m each direction from the center.
Maybe have the system with dolly and two sensors pointing out in a wide V - when a fencer moved forward or back out range, sense that and move the dolly to get him back in range. Maybe have the sensors aligned more perpendicular, out in 2m arms, for better sensitivity?
sorry if this was unclear I plan on having the dolly 10m long as I think that would be enough to capture 14m on camera thanks for the ideas. do you think something along the lines of a bike computer on the overheads might work? if I do that I would need to track the dolly.
You could maybe use a BLE module on the persons to act as beacons. Then you can measure the distance from each person individually and adjust the dolly to the middle. Tale a look at RFduino.
You could maybe use a BLE module on the persons to act as beacons. Then you can measure the distance from each person individually
Don't be silly, you can not get that sort of information from a blue tooth module.
Just Measure the RSSI from each beacon. You don't even have to pair it.
Just Measure the RSSI from each beacon.
That idea occurs to lots of people, but anyone who has actually experimented quickly learns that RSSI values don't vary much with distance. They vary much more strongly due to relative antenna orientation, nearby reflecting/absorbing objects and so on.
Basically, it doesn't work.