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Re: [TowerTalk] OR-2800PX Point and Shoot?

Subject: Re: [TowerTalk] OR-2800PX Point and Shoot?
From: Pete Smith <>
Date: Fri, 04 Mar 2011 17:09:27 -0500
List-post: <">>
Maybe no need to reinvent the wheel, *if* the 2800 can be equipped with 
an RS-232 port, and if it emulates one of the well-known rotator protocols

73, Pete N4ZR

The World Contest Station Database, updated daily at
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On 3/4/2011 3:40 PM, wrote:
> Hi Dan,
> Very interesting input regarding the point and shoot issue...
> It's a bit over my head but I will look into it.
> Many Thanks and 73,
> Ted  K2QMF
> On Thu, 3 Mar 2011 09:44:40 -0500 Dan Zimmerman N3OX<>
> writes:
>> I think your easiest bet is to use a computer and software like
>> DXLab.
>> If you don't want a general-purpose computer in the mix, or if you
>> really,
>> really want a knob, I'd look at talking to the RS-232 interface
>> with
>> something like an Arduino (,
>> or other beginner
>> microcontroller
>> board.  I like the Arduino because the language is simple, there is
>> a large
>> community of total newbies using it,  and the board is all-in-one
>> and
>> programmable over USB.  If the M2 control box is true RS-232 (with
>> plus and
>> minus twelve volt logic levels) you probably need a MAX232 (
>>  level converter chip between
>> the
>> Arduino and the M2... but that's one chip and a few capacitors.
>> I can't design the firmware for the thing, especially without
>> knowing the M2
>> controller's language or having one to test on, but it might be as
>> simple as
>> something like this:
>> 1) in the firmware,  set up a serial connection and a digital input
>> for a
>> button (analog input is set up automatically I think)
>> 2) Read the position of a potentiometer (the "point" pot) on one of
>> the
>> analog inputs using the function AnalogRead().  This gives a number
>> from 0
>> to 1023 for a wiper voltage between 0 and the power supply of the
>> controller
>> board.  Translate to a heading as desired (depends on the pot you're
>> using)
>> 3)Read the digital input using DigitalRead().    if the button (the
>> "shoot"
>> button) on the digital input is pressed, send the pot's heading to
>> the rotor
>> using Serial.Print()  (this switch should be "debounced" by reading
>> it twice
>> maybe 5-10 milliseconds apart and only considering it to be pressed
>> if both
>> of those are the same)
>> And that's pretty much it if the box accepts a heading in degrees as
>> a
>> command.
>>   You probably want a 360 degree pot, which might be a little hard to
>> find.
>>   And if the rotor is capable of more-than-360 degree or continuous
>> rotation,
>> you might need to be careful in how you send your commands.   That
>> is,
>> unless the rotor controller itself decides which way to turn based
>> on the
>> heading that comes in on the serial port.  If it does that, it
>> greatly
>> simplifies things, and you just send a number over the serial port,
>> probably.  If the homebrew controller has to be smart about
>> over-travel past
>> 360 degrees, you'd need to add a lot of rules to the firmware to
>> tell the
>> control box the right direction.
>> You can probably do it for thirty bucks or so, plus the effort of
>> learning
>> how to program the Arduino board... but like I said, there's a
>> large
>> community of people who don't have any prior experience with
>> microcontrollers doing things with the Arduino, because the people
>> who
>> designed it were shooting for "as easy to use as possible."
>> Here are some things I've built:
> ing-Arduino&p=112644#post112644
>> The first one accepts input from analog and digital pins and turns a
>> switch
>> to switch bands on my big vertical.  The second one is an automated
>> band
>> switch that sends and receives commands from Ham Radio Deluxe over a
>> USB
>> serial connection and switches eight lines high and low.  Eventually
>> I'm
>> going to fuse those two things together...
>> 73
>> Dan
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