DIGITAL Radio Control?
Bill Chennault
Posts: 1,198
All--
Gee. I looked at radio control transmitter prices and decided (very quickly) that you have to be truly SERIOUS about RC to get into it at the level I desire.
So, I wondered why a person couldn't just take a couple of Stamps and two 912 MHz RF tranceivers and implement their own digital radio control. You could make up an instruction set (I have had some success doing that!) and have the "master" Stamp send a byte to the "slave" Stamp on the remotely controlled device (lawn tractor, in my case). There are plenty of input pins available to which push buttons could be connected (left, right, stop, back, blah, blah, blah).
Upon byte receipt, the Stamp on that end would interpret the byte sent as the command and implement it accordingly. Using the 912 MHz tranceivers would provide significantly greater range (I would like to cut my neighbor's grass, too; I figure ten bucks a cut), plus give me the ability to make the lawn tractor a robot later on when all mechanical issues are solved.
This MUST have been done before. Does anyone have any input or guidance for me?
Thanks!
--Bill
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You are what you write.
Gee. I looked at radio control transmitter prices and decided (very quickly) that you have to be truly SERIOUS about RC to get into it at the level I desire.
So, I wondered why a person couldn't just take a couple of Stamps and two 912 MHz RF tranceivers and implement their own digital radio control. You could make up an instruction set (I have had some success doing that!) and have the "master" Stamp send a byte to the "slave" Stamp on the remotely controlled device (lawn tractor, in my case). There are plenty of input pins available to which push buttons could be connected (left, right, stop, back, blah, blah, blah).
Upon byte receipt, the Stamp on that end would interpret the byte sent as the command and implement it accordingly. Using the 912 MHz tranceivers would provide significantly greater range (I would like to cut my neighbor's grass, too; I figure ten bucks a cut), plus give me the ability to make the lawn tractor a robot later on when all mechanical issues are solved.
This MUST have been done before. Does anyone have any input or guidance for me?
Thanks!
--Bill
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You are what you write.
Comments
Do you need or just want bi-directional comms (tranceivers)?
I did it because I already had everything but the radios. I also have a mess-o-RC gear, too. I'd advise that you do a bit more homework before you start plunkin' down your cash. You can get a·fair RC-TX·and a good RC-RX for well under $100.
Two BS1s + a CHEAP RF link = $70. Writing the software to control it all = PRICELESS.
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I'm not a complete idiot! Some of my parts are missing.
I want bi-directional communications so that I can eventually implement a robotic device upon my radio controlled machine. As far as the number of channels, I would like to have enough to do many things: I want to pull a mower deck and be able to control its gasoline engine (RPM, choke); I want to pull a weed-eater "deck" and be able to control the position of the weed-eater in several degrees of freedom;·I want to pull a vacuum to suck up the cuttings and maybe a few other things.
Pretty soon, 15 channels does not look like enough. However, 255 codes looks like more than enough especially when none of it has to happen very quickly. The expensive component will be the wireless WiFi tilt/pan camera with both optical and digital zoom. It has to have enough resolution so that I can see what I am doing.
I will put an 802.11g laptop on the deck and cut the back yard and whatever else the wifi and camera range will let me do.
This is not a commercial effort. It is just for my own satisfaction.
If you have any ideas, I would love to read them.
--Bill
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You are what you write.
I'm partial to the xBee Pro stuff. It's got enough range for the sort of thing you want to do, it interfaces easily to Stamps, particularly using Martin's xBee adapters, and it does all its own error detection and correction. As far as a Stamp or Propeller is concerned, it's just a bidirectional serial port.
You can just use a "line" for a command with the first two or three characters being a destination or command code (for the function to be done) followed by any information needed separated by commas and ending with a return. Best to have every command followed by a response so the sender at least knows that the receiver (function) was satisfied with the command.
When looking at the specs, pay attention to the receiver. Anything with sensitivity worse than -110db is a toy.
Mike, thanks for the xBee leads. I certainly need to investigate them . . . they sound dirt easy.
jmalasia, a very good friend at the top of the marketing business once asked me if I knew what "marketing talk" was. I fumbled around and finally said no, I didn't. He said, "Lying."
I know about true digital radio, but did not want to go into a lengthy explanation because I also knew that everyone here would understand what I meant. However, I did not know to look at the receiver's db nor did I know that to achieve advertising distances one must measure them on the dark side of the moon. Thanks.
--Bill
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You are what you write.
More specific details, please? Or has everyone here already snatched everything up?
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I'm not a complete idiot! Some of my parts are missing.
Saneo 2611CB3-Plus Deluxe
Senao
If I could only Spell
http://cgi.ebay.com/Senao-Engenius-EL-2611-CB3-Deluxe-Access-Point_W0QQitemZ220237677997QQihZ012QQcategoryZ44997QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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I'm not a complete idiot! Some of my parts are missing.