Adding Wireless Connectivity to the LI-6400XT
In Five Easy Steps
Introduction
Wireless connectivity for the LI-6400XT has been a frequently
requested option, mostly to enhance the ease of remote
control of the instrument or to provide an easier way to
download data. Although not a native feature, it is possible to
modify the LI-6400XT to either join or create a wireless
network through the addition of a modified Apple AirPort
Express
™
. This document will detail the steps needed to add
wireless capability to the LI-6400XT. Note that this modifica-
tion works only for XT instruments since it relies on connect-
ing the LI-6400XT via Ethernet to the AirPort Express.
Required Equipment
●
Apple Airport Express Base Station (MC414LL/A)
●
DC-DC adjustable step-down voltage regulator (we used
Arrela Lm2596)
●
Red and black 22 AWG wiring
●
Controlled DC power supply
●
DC voltage meter
Required Tools
●
3/4" putty knife and/or flat-head screwdriver
●
3M Double-sided urethane foam tape
●
Red and black 22 AWG wiring
●
Torx T8 screwdriver
●
Torx T5 screwdriver
●
Solder and soldering iron
●
Nail polish or threadlock
●
Wire stripping tool
Step 1: Disassembling the Apple AirPort Express™
Base Station
First and foremost, verify that the AirPort Express works
before performing any of the subsequent steps below. Plug it
in, power it up, and make sure you can connect to it and
access the firmware using the software provided by Apple.
This assures you that if you have a defective router, it is
addressed before you (A) go through making the modifica-
tions, and (B) before you void Apple’s warranty.
The AirPort Express is not designed to be taken apart by end-
users; nevertheless, with some patience and the judicious
application of force, it is possible to open the outer case
without destroying the router. To do this, start on the side of
router that contains the small LED. Begin prying with a
flathead screwdriver or putty knife to the right of this side’s
center. When the side starts to open up, move to the next
Continued on next page
side, taking care to not pry directly on the center connector
resides. Continue prying each side, off-of-center, until the top
of the AirPort Express is off. Note that the internal corner
connectors will likely break off while removing the top cover;
this is okay as long as the internal center connectors are not
broken. Needless to say, you have voided the warranty
provided by Apple at this point.
Once the AirPort Express is open, you should see something
similar to Figure 1. The goal now is to remove the power
supply and replace it with the voltage regulator. The power
supply is under the “L” shaped metal cover that is highlighted
in Figure 1. There will be five screws that need to be removed
to get this cover off. These screws require the Torx screwdriv-
ers listed above. When the metal shield is off, continue
removing other screws holding down the circuit board; the
entire circuit board needs to be removed from the AirPort
Express case before it is possible to take out the power supply.
The removed assembly should appear as in Figure 2.
Figure 1.
AirPort Express with top cover removed. The AC to
DC converter is located under the L-shaped metal cover.
Ground and +3.3V terminal connections also shown.
Figure 2.
AirPort Express with internal components removed
from the plastic housing. The power supply can be removed
from the other components at this time (highlighted above).
