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Subject: 
Re: replacement for IR-communication
Newsgroups: 
lugnet.robotics
Date: 
Tue, 7 Oct 2003 08:27:49 GMT
Viewed: 
1515 times
  
We have done this. That is retro-fitted an RCX with a bluetooth module. It
involves hardware hacking the RCX, which will "void the warranty". Don't do it
unless you can afford to completely break your RCX, and can afford a spare!

Can I ask, are you prepared to hack the RCX? It can be a bit dodgy and our first
effort  is currently broke, cos it has stopped talking to me; probably one of
several dodgy solders... If you are prepared, please find below some resources.
Just be careful! The alternative is to adapt a serial tower and plonk it in
front of the RCX, which is definitely much easier once the BT module is
configured, but slower.

Here was our test set up, as described in a recent paper for the Reading
University On-line and Internet Robots Workshop:

Well it was running. Some very dodgy soldering straight onto the motherboard
of the RCX. Here are the specs:

1) Free2Move Serial plug - supplied caseless, but borrowed from another project
http://www.free2move.se/prod_spp.htm

Wired into...

2) Max 233 serial buffer chip - not strictly necessary, but prevents the RCX
from frying
http://dbserv.maxim-ic.com/quick_view2.cfm?qv_pk=1798

Note, I adapted the following technique from hacking my cybie! Details at:
http://www.aibohack.com/icybie/sic_rs232.htm

Wired into...

3) A variation on the following hack to get RS232 on the RCX
http://oase.uci.kun.nl/~mientki/Lego_Knex/Lego_electronica/IR_tower/IR_tower
.htm

Or more properly from Peter Balch's original:
http://www.abs-robotics.com/other/hardwire.htm

My variant involved cutting the ground link for the IR transmitter/receiver
and rewiring to a switch (turn IR on and off). Further dodgy solder
connections to the surface mounted Processor:

http://www.geocities.com/swatson001/research/images/pin_arrangement_large.gi
f

TX RX and GND are the critical pins, just like for the Cybie thing above.

Got this from:
http://www.geocities.com/swatson001/research/rcx_internals.html

But more info from:
http://www.renesas.com/eng/products/mpumcu/8bit/h8300/3297/index.html

4) I use a Mac OS X with the D-Link USB Bluetooth adapter, paired with the
free2move device and set up an outgoing serial port using the Mac Bluetooth
configuration software. This virtual port is then visible to the Robolab
software. This is the least scalable, transferable bit of the system, but
should be doable on a Windows PC; I just don't have that kit available yet.

Lots of good general RCX info from:
http://www.daimi.aau.dk/dArk/Vaerktoejer.dir/RCX.vejledning.dir/Vejledning.h
tml

And
http://graphics.stanford.edu/~kekoa/rcx/

OK, here are the specs for the various sources of BT module items that you will
need:

Bluetooth-2-serial devices:

Free2Move - these are the ones we would recommend, but the others are equivalent
F2M01C1-000 Standard Serial Port Plug (With plastic housing) 200 EUR/unit
F2M03C1-001 Class 1 Bluetooth module with Wireless UART firmware 60 EUR/unit
F2M03C2-001 Class 2 Bluetooth module with Wireless UART firmware 60 EUR/unit
First is for the PC, the second and third are for embedding, the latter has a
longer range, but higher power requirement.

TDK - Intelligent Serial module and serial adaptor board for embedding
TRBLU20-001A0-02 Intelligent Serial Module £79.00
TRBLU20-00200-01 Serial Adaptor Mother Board With Starter Guide £90.00
Must be purchased from: http://www.tdksystems.com/bism/wheretobuy

Brainboxes - BL-521 RS232 Bluetooth Convertor £128-95 (£151.52 inc VAT)
Must be ordered from the following url: http://www.serial-cards.co.uk/bl-521.htm

We have to receive some more bluetooth kit before we can go wireless with the
camera, but are going to use the CMU-cam (which has a serial link and java based
software) with two BT modules when they arrive. Here is the kit spec:

CMUCam Vision System $109 + $43.57 P&P = $152.57 (~£103)
Details at: http://www.robotstore.com/catalog/display.asp?pid=381

There are a couple of other bluetooth modules available now - some in OEM
format, which are good for TINI interfacing - one from TDK and one from
Brainboxes; there are probably others too, but you probably want the BT - RS232
adapters, and look for ones with low power requirements. The 100-200 metre range
devices overcome the shielding of the RCX casing much better, but take a lot
more umph from the batteries; I am told this, but haven't verified it. They all
range from £30 (for bulk) to £80 (for singles).

You will need to hook a pc with hyperterminal to the RCX bluetooth modules to do
the pairing, before hooking up to the RCX. When we redo the broken one, it will
be with a stereo jack socket so that we can plug in the Bluetooth device
externally.

Most basic PC modules can deal with up to 7 external devices, but some can only
handle 1 Bluetooth device at a time. With a proper piconet device for
interacting with the BT modules, this can be higher. One we are hoping to use is
the Sony Ericsson Blipnet device. Details are here:

http://www.ericsson.com/about/blipnet/
They sell these but can also be bought from:
http://www.blueunplugged.com/shop/detail.asp?productGroupID=191&deptID=13

Dr. Mike Reddy, RoCCoTO Project Scientist
--
Email: mreddy@glam.ac.uk
Snail: Centre for Astronomy and Science Education (CASE), University of
Glamorgan, 4 Forest Grove, Trefforest, Pontypridd, RCT. CF37 1DL
Tel: +44 (0)1443 482240 Fax: +44 (0)1443 654114



Message has 1 Reply:
  Re: replacement for IR-communication
 
That seems like a very expensive solution. Isn't there a cheaper way? Also, could there be an internal solution (keeping everything inside the RCX and tower)? Rob "Mike Reddy" <mreddy@glam.ac.uk> wrote in message news:HMDouD.Dww@lugnet.com... (...) (...) (21 years ago, 9-Oct-03, to lugnet.robotics)

Message is in Reply To:
  Re: replacement for IR-communication
 
If it is so easy to change the send/receive method on the RCX, why hasn't someone already done it? My thought was to figure out how the Cybermaster RF components could be used on the rcx instead of the RCX's IR. I would absolutely love to see (...) (21 years ago, 29-Sep-03, to lugnet.robotics)

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