Author Topic: My RC idea (feedback apreciated)  (Read 4447 times)

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Offline jklvTopic starter

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My RC idea (feedback apreciated)
« on: September 18, 2007, 12:34:33 PM »
« Last Edit: September 18, 2007, 01:15:32 PM by jklv »

Offline paulstreats

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Re: My RC idea (feedback apreciated)
« Reply #1 on: September 18, 2007, 01:43:44 PM »
I thought of a similar idea a couple of months ago, it works like this:-

The transmitter can send digital data over time, which the reciever collects and sends to an mcu. The mcu can then interpret a digital binary signal and provide more than just the 2 regular channels of outup.
 You could even use more than 1 device per frequency if you could encode an id into each mcu linked receiver

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #2 on: September 18, 2007, 02:06:12 PM »
I thought of a similar idea a couple of months ago, it works like this:-

The transmitter can send digital data over time, which the reciever collects and sends to an mcu. The mcu can then interpret a digital binary signal and provide more than just the 2 regular channels of outup.
 You could even use more than 1 device per frequency if you could encode an id into each mcu linked receiver
I did not understand that :S
what is mcu?
Could you make a diagram plz?

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #3 on: September 19, 2007, 01:27:38 AM »
So any feedback? I imagined this because the more the channels the higher the cost of a TX and RX, so if this is possible, I will be very happy xD.
If this does not work, I am thinking of connection between remote operator and bot to be via cellphone. Anyway, still got to do research, a lot of it.
Edit: I believe 1 more micrcontroller will be needed, so it will send modulated info to the transmitter.
« Last Edit: September 19, 2007, 03:11:05 AM by jklv »

Offline paulstreats

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Re: My RC idea (feedback apreciated)
« Reply #4 on: September 19, 2007, 04:47:52 PM »
This is possible quite easily i would think, but it would be easier with a 2 channel system so you can use 1 for rx and 2 for tx to transmit and receive serial data. or you could also use 1 for scl and 2 for sda for an i2c type system.

An easy way to set it up is to take apart a cheap radio control car, most are 2 channel i think. take the board out of the car and disconnect the motors, these should be able to be used to collect a digital signal, maybe you would need to use something to increase/ reduce the signal.

then take apart the controller and remove the board. remove the potentiometers (the things that control the steering and acceleration) the wires that connect the potentiometers when put together will transmit a signal, so if you touch them together then take them apart again, you have transmitted an 10 signal, do this 4 times and you transmit an 10101010 signal, obviously you need some kind of control system such as a baud rate or use 1 of the channel as a clock line and the other as a data line.
 I'll try and post some pictures 

Offline dunk

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Re: My RC idea (feedback apreciated)
« Reply #5 on: September 19, 2007, 05:18:25 PM »
hi Jklv,
if you are going to be using micro controllers any way i don't see the advantage of using a commercial R/C unit.
you can buy RF pair of transmitter and receiver modules for as low as #10.
connect each of these to a micro controller's UART and you have as many channels as you have I/O pins on your micro controller.
here's a 2Ch example that could be easily scaled up:
http://www.serasidis.gr/circuits/RF_remote_control/RF_remote_control.htm

search for conversation on this forum for "radio module UART" etc as it's been discussed before.


good luck,

dunk.

Offline TrickyNekro

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Re: My RC idea (feedback apreciated)
« Reply #6 on: September 19, 2007, 11:08:02 PM »
And if you are going to buy a RF pair see the TXM - 433 - LR and RXM - 433 - LR by LINX...
I don't want to advertise but take a look at their range!!! 3.000 feet and about 915m!!! Wow!!!
And they are el' cheapo... The ready to work modules... at least 10$ more!!!

Regards, TrickyNekro
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #7 on: September 20, 2007, 04:00:43 PM »
hi Jklv,
if you are going to be using micro controllers any way i don't see the advantage of using a commercial R/C unit.
you can buy RF pair of transmitter and receiver modules for as low as #10.
connect each of these to a micro controller's UART and you have as many channels as you have I/O pins on your micro controller.
here's a 2Ch example that could be easily scaled up:
http://www.serasidis.gr/circuits/RF_remote_control/RF_remote_control.htm

search for conversation on this forum for "radio module UART" etc as it's been discussed before.


good luck,

dunk.

Thanks a lot! ;)
Hope there was a tutorial

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #8 on: September 21, 2007, 01:55:47 AM »
OK, so here is what I understood:
The solution is not really to control more servos with only one channel, but to use a Tx Rx module attached to a UART which will be attached to the MCU, and have as many channels as the number of pins I have (nP=nC). Now about the Tx and Rx modules, do I need crystals? Which channels will I have?

Here is the comparison:
-Commercial Rx Tx costs would be about 50 dollar for a 5ch Tx and 50 for a 5ch Rx plus crystals. And the total would be +$100
-Homemade R/C will cost about $30

Glossary:
Rx = receiver
Tx = Transmitter
MCU = Micro controller Unit
UART= Universal asynchronous receiver/transmitter
nP = number of pins
nC = number of channels

I will be researching anyway.
Thanks a lot everyone, specially dunk and trickyneckro, by the way, do you have the page of the RF pair you posted? Thanks

Offline TrickyNekro

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Re: My RC idea (feedback apreciated)
« Reply #9 on: September 21, 2007, 05:02:22 AM »
UART is not something you attach... It's a protocol!!!
It's a way of transmitting data!!!
You need a TX module to send data in UART format and then a RX module to receive the data...
And you probably need two microcontrollers... (one to send the data and one to receive via the RF modules)
Now the number of the channels you want (for the remote) is equal to the Bytes you sent!!! (or the sum of transmitted data)
So if you want many channels you probably want to buy a module which can sent data in a high rate!!!! ( kb/s )

If you need anything else... post it here...
Cheers,
TrickyNekro!!!
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #10 on: September 21, 2007, 09:44:14 AM »
So UART is software?

« Last Edit: September 21, 2007, 10:07:22 PM by jklv »

Offline TrickyNekro

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Re: My RC idea (feedback apreciated)
« Reply #11 on: September 21, 2007, 10:23:13 AM »
Well... you can say so...
Literally it's a method!!!
A method of transmitting data!!!
For example the serial port of your PC transmits in UART
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #12 on: September 21, 2007, 10:38:00 AM »
What about crystals?
I do know the basics of Radio frequency.
Before moving on, isn't it possible to control more than one servo per channel?
I will need to micro controllers, the one I use, and the one the robot uses, both will be Tx Rx as I will be receiving data and sending, the robot will be too.
I need it to be about 1 mile range.
To make it easier, I am building a UAV, but not as usual RC hobbyist, I want to control it from my laptop, be able to operate it anywhere, etc. However this is only the planning part. Expected UAV frame is already made, so at this time I am only planning electronics and software (the hardest parts).
So the operating frequency will be 2.4Ghz, this frequency has about 40  or 50 channels, that is why, to avoid cost and probable interference because of other people using this channels, is why I wanted to use one channel only but I believe it is not possible.
Or am I not understanding?

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #13 on: September 25, 2007, 11:14:35 AM »
bump?

Offline snow

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Re: My RC idea (feedback apreciated)
« Reply #14 on: September 25, 2007, 03:26:08 PM »
2.4Ghz and 1 mile... visible range only i believe.

You can use 2 servros on same channel but they will turn the same. Google for Y-cable.


What is wrong with RC plane transmitters and receivers? You can get like 6(7?) channel stuff. Ah from laptop... probablly there are some RC transmitters that can be controlled via computer. Dunno for sure.

Offline h3ro

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Re: My RC idea (feedback apreciated)
« Reply #15 on: September 25, 2007, 06:44:27 PM »
Also, its not to hard to hack a rc controller to work from a computers serial port. Even I manged to do it as my first project.

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #16 on: October 08, 2007, 02:37:32 AM »
Also, its not to hard to hack a rc controller to work from a computers serial port. Even I manged to do it as my first project.
Do you have a tutorial?

Offline jklvTopic starter

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Re: My RC idea (feedback apreciated)
« Reply #17 on: October 08, 2007, 02:39:02 AM »
2.4Ghz and 1 mile... visible range only i believe.

You can use 2 servros on same channel but they will turn the same. Google for Y-cable.


What is wrong with RC plane transmitters and receivers? You can get like 6(7?) channel stuff. Ah from laptop... probablly there are some RC transmitters that can be controlled via computer. Dunno for sure.
Commercial RC RX are way too expensive

 


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