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What is the "best" way to control the #thing#? - Printable Version

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What is the "best" way to control the #thing#? - Matti Övermark - 02-19-2008

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

Re: What is the "best" way to control the #thing#? - Thomas Chrapkiewicz - 02-19-2008

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.


Re: What is the "best" way to control the #thing#? - Kareem Mokdad - 02-19-2008

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

Re: What is the "best" way to control the #thing#? - Garth Wilson - 02-19-2008

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 . )

Re: What is the "best" way to control the #thing#? - Egan Ford - 02-19-2008

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

Re: What is the "best" way to control the #thing#? - John B. Smitherman - 02-23-2008

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.