Modding Palm IIIc to be a Remote Control

Palm IIIc - like all hand held orginizators/computers have a puny, weak IR transmitter .
Such transmitters are unidirectional and more annoying than useful for CIR purposes.
This page shows how I modified the Palm by adding additional amplifier & IR diode .

The goal:

...Is to make two Palm IIIc become wall-mounted , and present an convenient home automation menu, with the most used functions.
Every IR code is received by an computer that controls "everything" using IR , X10 and TCPIP


Disconnecting battery connector will cause total loss of memory, you should use the free "BackupXfer" to do a complete backup of your Palm before starting.
Opening your Palm and messing with it will void any warranty - if any. /(this are old, discontinued devices)
If you test the device while disassembled - be careful with the high  voltage line (backlit) - it  is switched to few hundred volts, and will not only be able to give you a shock, (not lethal to healthy people) but (even worse) this voltage can travel thru your fingers and destroy the electronics instantly.

Locating IR signal.

First : locating  the TX signal , that usually controls the LED driver inside the SIR2 module - it is the second pad from right.
I soldered three twisted enamel-isolated wires to it - this is what I'll call the TX signal from now on...

Locating Power

The blue line shows a pad that is GND
The red, shows a pad that is Vbatt - battery voltage - by using it - I will not disturb/overload the 3.3v regulated power line that  this device needs.

Choice of components:

I did not had any IR diode in house this evening, so I used one diode I took from an old remote control.
Only one additional component is really needed. - an digital MOS-FET.
I chose the FDV303N - an SO8 digital N-channel FET with 2A peak current.(its perfect - as IR remotes sends not more than 150us long pulses)
This MOS FET is also ESD (Electro Static Discharge) protected, and therefore fits well to the job - I plan to have an external diode.

This picture shows the SO8 size  - compared to a jumper, a "thin" wire and a match.

Putting it all together:

Remember:  it's no problem if you reverse the IR diode - it won't work - but nothing will go wrong.

Solder the FDV303N's Source pin to the TX signal pad (the second pad from right in the MINI SIR2 module.).
Connect the FDV303N's Gate pin to the GND pad. (see picture with blue line)
Connect the +Vbatt pad  to the IR LED's  Anode. (see picture with red line)
Connect the FDV303N's Drain to the IR LED's  Cathode.

It should look somewhat like this:


The circuit should work now, no matter what IR software you use /(OmniRemote pro , ProntoLite  or other) this circuit will work..
This circuit is THIS powewrful:
- you can notice the IR diode(s) will get hot after a while with much activity.
- you can connect two diodes in serial  for greater range.
- you can connect two or more diodes in paralell  for greater range.
- this MOS FET  provide spikes up to 2A - and the battery + capacitors can deliver it - it's awfully much power.

External connector:

In case you would like to use the Palm as a mobile device - You can do like this:
Just glue an (2.54mm pin header) connector in side the casing, this connector can then take a IR diode when needed - stright pins or in any angle.


  External connector with  a bent diode  that will, when mounted on wall, point in the direction of my living room.


      Preparing for wall mount:

            The Palms I've got  had broken/defect back-lids - they would not stand in the cradle,   so I gutted the cradles, and soldered the wires directly on the Palm,  The "Sync" button can be seen.
            This way the palm can be mounted on wall, (you can see the velcor strip)  - taken down, and sunchronized with each other using backup/restore function of BackupXfer.


     An very early example:

          on wall:


             Thanks goes to Vidar S. for giving me these two Palm IIIc.