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Full Version: What is the "best" way to control the #thing#?
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I have a 41-CX, a 71B with a single HP-IL module and some 48SX/GX and a 50G. However my electronic knowledge is rather limited, very limited compared to all Gurus writing here, I am still nursing an idea of a project where I could use one or more of the above mentioned calcs to do some real world controlling. Like switching on and of a lamp or whatever funny engineering #things#. I would prefer to control the #thing# in such a manner that it would not need any AC-sources for the control.

How to do it? Anyone?

/Matti Sweden

RS232 is the simplest method of machine interface.


- Simple; that is, easy to understand.

- Generic interface - no drivers required - control can be via simple ascii commands from a simple terminal program(or the HP48 XMIT/SRECV commands).

- Generic Device interface - via a PIC or other simple micro. Simple bit-banging and supported on PIC with High Level Language compilers.


- Disappearing (or disappeared) from PCs - although I understand some motherboards still contain the old 'COM' port - they are not wired externally. (There are low cost USB<-> RS232 cables available)

- Slower than USB

When developing #thing# to communicate over RS232, it is helpful to be able to test the #thing# from either the HP48 or the PC, with no drivers or other overhead required.

I've interfaced both generic PICS and X10 controllers to the HP48 successfully.


Well, you should already be able to turn your 48gx or even 50g into a TV remote ;)

HPIL has a very intelligent and complex protocol that is definitely beyond the casual electronics hobbyist. But, with the appropriate interface converter, for example the HP82169A HPIL-to-GPIB, HP82165 HPIL-to-GPIO, or the HP82164A or FSI 164A HPIL-to-RS232, the range of interfacing is limited only by HPIL's speed; so for example real-time videos would be out of the question, but the ability to interface the 41 to a lot of pieces of IEEE-488 (GPIB) lab instrumentation at once is what got me away from TI and onto HP.

E-mail: wilsonmineszdslextremezcom (replace the z's with @ and . )

RS232 is my preferred way.

You might find the following articles of interest:

Control the World with HP-IL/RS-232/41CX + X10

Explore the World with HP-IL/RS-232/71B + GPS

Hi Matti. You may be able to buy similar products in Sweden such as:


Another good product to have around to help measure and evaluate power usage is the Kill-A-Watt:


I hope that this helps and good luck.