How to build a radio card

version française

Introduction
I  components list
II  usefull tools
III manufacture stages
IV  if the card doesn't works ...
V  softwares
VI usefull links

Conclusion

Introduction

There is a documentation where you will find the components list and all the explanations you need to build a radio card for your hp49g or hp48g/g+/gx.
The carried of the card is 35 meters (tests where realised); you can connect the card on your calculator whith the hp-pc cable .

 

I  components list

You must have all this components to build your radio card:

A Velleman TX 433 transmitter

An Auriel-RF290 A-5S Aurel receiver

2 diods 1N4148

One 470 Ohm resistor

1 wire for 9V battery

1 DB9 male pin

some wire

2 metallic antennas of 15 cm

The circuit
here is the typon of the circuit


II  usefull tools

You will need some tools:
  - an iron to solder
  - some tin
  - a peg to bare
  - a blade peg
  - a small drill (if there is no hole in the circuit)

 

III  manufacture stages

If you have all the equipment, you can build your card !
If the holes are not drilled, you must drill them now.
You must bare alimentation wires, cut 3 small wires (2 cm) and bare them

1) solder the alimentation:

2) solder 3 small wires on the db9 drive, on the broach 1, 3 and 4
____________________
\    *1  *2   *3   *4   *5     /
 \     *6   *7   *8   *9       /

3) solder the db9 pin on the circuit; Warning ! Wires of broach 3 et 4 must be crossed ! (see the picture)

4) solder the two diods IN THE RIGHT SENSE !!! (the black feature toward the outside of the circuit)

5) solder the resistor

6) solder the transmitter

7) solder the reciever

8) solder antennas

Your radio module is complete
He must look like this:


Iif the card doesn't works ...

It's not astonishing ... the construction of a  radio module isn't easy...

You can check some things:
1) did you buy teh good components ?
2) are they on the good place on the card ?
3) are diods in the right sense ?
4) soldering plots doesen't touch themselves
5) have you a good battery, is the module well connected to the calculator whith the hp-pc cable ?
6) is the software you use good ?

If you don't find the problem, you can buy a radio module (it cost only 50 $). If you are interessed, you can contact Yoann Désir (yoanndesir@yahoo.com).

 

V  softwares

There are two softwares: ChatHP and icqHP by Yoann Désir
Whith ChatHP, you can chat with an other hp-user;
With IcqHP you can exchange files and messages using the radio module
If you want more information about IcqHP, you can visit the official web site www.multimania.com/icqhp

 

VI  useful links

Here are some sites where you can find some informations about radio modules:
www.lebebert.fr.st : origine site of this documentation .
www.multimania.com/hp49g : Yoann Désir's site, where you can download last versions of Chat HP and Icq HP .
www.multimania.com/icqhp : a site where you will find the last version of Icq HP and a detailled documentation about it.

Conclusion

I hope you have anderstand all the explanations and you will succeed to make your own card; it's intersting to make it, and this type of communication is impressionnat for a calculator ...

Bebert