proximity sensing

[signal15]

I just picked up one of the active RFID packages from Cliste Electronics. It came with a receiver, four 8-meter tags, and two 40 meter tags. The tags each broadcast a unique ID, and when the receiver picks them up, it outputs the ID on the serial port. My intent was to integrate this with the ELK M1 Gold, but the ELK requires received serial data to end with a carriage return. Unfortunately, the device outputs a space after each ID instead. So right now, I'm using socat on a linux box to pull the data in, pipe it through "tr" to convert the spaces to carriage returns, and then pipe it back out another serial interface. It's not optimal, but I'm trying to get the source code for the unit so I can program a new PIC chip that gives me the output I want without having a computer in between.

The other thing I found is this:
https://shop.openpcd.de/index.php?cPath=27&...a31bipdh19t1ae7

These look very interesting, and it gives you RSSI values for position guesstimation. Of course, there's no way I know of in the ELK to perform the logic needed to determine position, just whether or not the tag is in range. So you would need to run it through a script on a linux box to massage the data and tell the ELK what to do with it.

 

[electron]

Keep us posted on the firmware issue, I'm not sure why they wouldn't use carriage returns to begin with.

The OpenBeacon stuff is pretty promising, they used it at HOPE once, and it seemed to work pretty well. Nice to see they are selling the hardware now, just wish it was a little cheaper (~$500 USD).

 

[signal15]

For reference, here is the command that I'm using to get the data in the RF8315 into the ELK:

socat /dev/ttyS0,raw,b9600\!\!TCP:10.2.2.45:2101,crnl exec:"tr '[:space:]' '[\n*]'",pty,raw,echo=0

To keep it running after you logout, prepend the above with "nohup" and append it with "&". I haven't put it in a startup script or done anything to make it reconnect automatically if it loses connection. The IP is obviously the IP of the M1 ethernet expander. You could pipe it out a second serial port if you wanted to instead. If you connect with ELKRP, then it stops interpreting data from the RF8315 until you disconnect. I have a serial port expander on the way to avoid this.

This was a pain in the butt to come up with, but the developer of socat graciously helped me troubleshoot it. I sent the manufacturer of the product an email, and they are sending me a replacement chip for the receiver that outputs a CRLF after each ID, so if this works, I'll be able to do away with having a separate machine in there. They should have done that in the first place since it's WAY easier to parse the data with an EOL delimiter.

You can get into the openbeacon stuff for less than $500. They have a USB receiver for around $80. True, you'll have to keep a separate machine running, but it could be an existing small device running DD-WRT or other embedded linux that you can compile the software for. You *NEED* a separate machine running with Openbeacon anyway if you want to make use of the RSSI data.

If only the ELK had an embedded linux/*BSD "gumstick" in it that you could use to do callouts to for more advanced scripting.