Need a wireless configuration solution to cover about 1 foot

Go To Last Post
9 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

That would be 30cm for the rest of the world. :)

What I'm looking for is a way to configure small modules with an address after they are installed, not using wires. The installer (person) would be at the location of the module, and will have the address to enter into the module. The need is to get the address into the module. The total data to be embedded is just a few bytes, certainly no more than 10. There may be a great many of these modules in an installation.

I was thinking of an IR solution where both module and installer tool have TX and RX to perform the configuration and verify it. Essentially the installer would point a configuration gun at the module, press the trigger, and a green LED on the gun would signify that the configuration succeeded. The module UART is already being used so this would have to be bit-banged, but since the module won't be doing anything else before configuration, that doesn't present any problems.

So, any comments on this approach, or suggestions of other approaches?

Mike

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

That is very similar to what I would choose. It does add to the power consumption if the IR is always on. You might add a small PMOS power switch that you turn on for a minute after a reset if it is an issue.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

kk6gm wrote:
There may be a great many of these modules in an installation.
...
or suggestions of other approaches?
Preconfigure the modules with addresses "in the factory".

If you use Xmegas, they have a unique serial number. If you use normal AVRs, then stuff like a Maxime DS1990A could provide a unique number. Or just change your programming procedure to add a unique serial number to flash or eeprom when initially programming the AVRs.

Stealing Proteus doesn't make you an engineer.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

What about the other foot? :roll:

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

ka7ehk wrote:
That is very similar to what I would choose. It does add to the power consumption if the IR is always on. You might add a small PMOS power switch that you turn on for a minute after a reset if it is an issue.

Jim

IR sounds like a good solution for communications. In addition to powering up the IR receiver after a reset as Jim suggested, you might consider a magnetic reed switch mounted next to the enclosure wall (assuming it is plastic) to initiate the programming / configuration mode. The led could also serve as an indicator that it was waiting for configuration.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Have you considered using said green LED as the receiver? Run it between two pins in reverse bias, and either a) measure differential voltage gain or b) measure capacitance change by pulsing one of the pins and observing discharge time. That should save a bit of BOM costs.

Alternatively, what about magnetic coupling? A simple multi-turn coil should couple kHz well.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I can see now that I may not have given quite enough information. The addresses will be composed of two parts, a net address and a subnet address. The subnet address will be 7 bits to allow 128 devices max (it's RS-485). The net address will indicate which of many 128-device nets, each driven by a higher-level net controller. The net address will only be used so the net controller can assure that all devices on its net are on the net they they they should be on.

So the goal is to install a module based on a master connection/location diagram, then tell the module its net and subnet according to where it has just been installed (the net/subnet will be pre-assigned on the diagram, perhaps in barcode form). Later each net controller can check for wrong-net modules and subnet collisions, which would indicated mistakes in the address assignments.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

kk6gm wrote:
... a way to configure small modules with an address after they are installed ...

Mike

Mike,

I don't have enough of the picture yet. Will this address be used to "communicate" the source identity of the module's data ... or perhaps to poll the network of modules for their data from a central device? Presumably the addresses need to be unique within the installation environment.

If you also wanted to know the temperature inside your module, you could use a Dallas DS1820 and use its 64 bit lasered rom code as your "address". Being unique, it also serves as your module serial number for warranty tracking purposes.

Just thinking out aloud ...

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

.... spit, spit ... my response above got gobbled/delayed by the AVRFreaks site lockup at 10:00 here. Apologies Mike.

Ross

Ross McKenzie ValuSoft Melbourne Australia