Pheetuz
Full Member level 3
Hi folks,
I'm doing a project at university and need a way of detecting when an object leaves a rough perimeter.
The project is roughly akin to a house arrest anklet but it needs to be smaller - to fit around the user's wrist. It must detect when the wearer is more than x (say 10 foot) from a certain point and then flash an LED on their wrist to alert them to this.
I was thinking of solving this problem by having a small RF transmitter constantly broadcasting from the fixed point in the centre of the perimeter and having a tuned circuit built into the bracelet periodically listening for the broadcasts.
The problem is that I have little knowledge of working with RF circuits and the transmitter and received would need to be very compact (a couple of cm^2 on each end) - would it be possible for me to detect over this distance in this footprint?
Could anyone point me at resources for potential antenna / circuit designs / any other useful resources. I am trying to do this as cheaply as possible which is why I was thinking tuned circuit instead of a prefab tx/rx IC.
I realise this post is a little vague but I am really just asking for confirmation that this is a plausable approach, and if so them for a little direction in developing a solution.
Thanks in advance, all comments are appreciated!
Pete
I'm doing a project at university and need a way of detecting when an object leaves a rough perimeter.
The project is roughly akin to a house arrest anklet but it needs to be smaller - to fit around the user's wrist. It must detect when the wearer is more than x (say 10 foot) from a certain point and then flash an LED on their wrist to alert them to this.
I was thinking of solving this problem by having a small RF transmitter constantly broadcasting from the fixed point in the centre of the perimeter and having a tuned circuit built into the bracelet periodically listening for the broadcasts.
The problem is that I have little knowledge of working with RF circuits and the transmitter and received would need to be very compact (a couple of cm^2 on each end) - would it be possible for me to detect over this distance in this footprint?
Could anyone point me at resources for potential antenna / circuit designs / any other useful resources. I am trying to do this as cheaply as possible which is why I was thinking tuned circuit instead of a prefab tx/rx IC.
I realise this post is a little vague but I am really just asking for confirmation that this is a plausable approach, and if so them for a little direction in developing a solution.
Thanks in advance, all comments are appreciated!
Pete