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yupng
Joined: 16 Jul 2008
Posts: 33
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 22 Sep 2008 14:24 RS232 |
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how to connect d RS232 to a wireless, so it can send data via wireless.
Anyone can help
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TekUT
Joined: 17 Jun 2008
Posts: 314
Helped: 22
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| 22 Sep 2008 14:51 Re: RS232 |
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There are plenty of wireless RX/TX with RS232 input but question is so more vague, you have also to define the frequency range (ISM, 433 MHz, ecc...).
For example you can look at the LPRS web site, one model that I've used in the past was the Easy Radio ER400TRS on 433 MHz at 19200 bps (http://www.lprs.co.uk/product_info.php?products_id=56).
Hope it help
Bye
Pow
Last edited by TekUT on 27 Sep 2008 10:58; edited 2 times in total |
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 26 Sep 2008 13:53 Re: RS232 |
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thanks for reply.
Actually i want connect RS232 to an infarad and send the data out. At receiver there, i received the data and change it back RS232 signal.
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Faizan Jawaid
Joined: 17 Jul 2008
Posts: 177
Helped: 17
Location: Karachi, Pakistan
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| 26 Sep 2008 15:27 Re: RS232 |
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| Use any IR led with phototransistor to make a IR circuit then connect it with TX RX just like an optocoupler.
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tkoWD
Joined: 21 Sep 2008
Posts: 9
Helped: 2
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| 26 Sep 2008 18:56 RS232 |
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To be able to connect the RS232 to IR you must understand how RS232 works. 12 volts sends '0', -12 volts sends '1'. When you want to Tx you want the led to light up. So you must modulate the input signal ( RS232 ) with the carrier frequency which you choose (e.g 90KHz with NE555 ), this will turn the IR EMITTER on/off. Pay special attention to the average current of the IR EMITTER. More current = more distance, too much current no distance...
On the receiver end you must filter out your signal from other infrared sources such as light, sun, convert the signal to RS232. Use an oscilloscope to visualze the signals...
the receiver has to filter the noise, amplify the signal, convert to TTL then to RS232.
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 27 Sep 2008 8:25 Re: RS232 |
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| tkoWD wrote: |
To be able to connect the RS232 to IR you must understand how RS232 works. 12 volts sends '0', -12 volts sends '1'. When you want to Tx you want the led to light up. So you must modulate the input signal ( RS232 ) with the carrier frequency which you choose (e.g 90KHz with NE555 ), this will turn the IR EMITTER on/off. Pay special attention to the average current of the IR EMITTER. More current = more distance, too much current no distance...
On the receiver end you must filter out your signal from other infrared sources such as light, sun, convert the signal to RS232. Use an oscilloscope to visualze the signals...
the receiver has to filter the noise, amplify the signal, convert to TTL then to RS232. |
Thanks for reply.
Do u have any example of this project? Is any wireless connection is more suitable and easy compared with using IR.
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tkoWD
Joined: 21 Sep 2008
Posts: 9
Helped: 2
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| 27 Sep 2008 12:35 Re: RS232 |
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I have these two pictures that i managed to restore from my harddrive, the transmitter and the receiver. You must use after the receiver a filter, a wave rectifier, a peak detector and a comparator. This is all i could remember hope it helps.
This is only one way of doing this but i guess there are many other ways, you must do some research
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tanuki
Joined: 11 Jun 2001
Posts: 90
Helped: 3
Location: Spain
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| 27 Sep 2008 13:56 Re: RS232 |
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Look at
http://irda.org/ standards for computer interfaces
also search: IrDA
There are IC's made for the purpose.
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 01 Oct 2008 7:26 Re: RS232 |
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I am trying to build an Infrared Transmitter and receiver that will take an RS-232 signal, convert it into TTL, then Pulse Width Modulation would be applied, and then finally transmitted. On the reciever side, basically extracting the orignal TTL signal from the Pulse Width Modulated signal and converting it back to RS-232.
Anyone can give me some guidance about this project?
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randell_xtian
Joined: 25 Mar 2008
Posts: 150
Helped: 8
Location: Philippines
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| 02 Oct 2008 6:22 Re: RS232 |
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hmmm, you used a MAX 232 and connect it to the TX and RX of that IC to the RX and TX of your device....
you can see the specification of what i'm saying to you find the specification of the MAX 232CWE on the net...
example:
MAX232 - Infrared Device
TX - RX
RX - TX
best regards,
randell_xtian 
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haerifar
Joined: 02 Feb 2004
Posts: 112
Helped: 1
Location: Iran - Tehran
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| 02 Oct 2008 12:57 RS232 |
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| i don't really remember but i know some chips existed that used for this propose by the way rfPIC also existed and you can use these series of micros
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 05 Oct 2008 2:42 Re: RS232 |
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if i want connect a wireless transmitter to RS232 for the purpose to transfer data from PC to another device. What is the suitable IC that i need to use? At the receiver there,i would like to change it back to RS 232. Actually i done a project (announcement board) which is transfer the data from PC to display device(dot matrix display). I transfer the data from PC through RS 232 port with using cable connected between RS232 port and display device. I need to improve my project to transfer data using any kinds of wireless connection. So anyone know which wireless transmitter and receiver suitable to replace the cable? Any suggestions?
Can give me any references.
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 15 Oct 2008 3:00 Re: RS232 |
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| tkoWD wrote: |
I have these two pictures that i managed to restore from my harddrive, the transmitter and the receiver. You must use after the receiver a filter, a wave rectifier, a peak detector and a comparator. This is all i could remember hope it helps.
This is only one way of doing this but i guess there are many other ways, you must do some research |
I am trying to build an Infrared Transmitter and receiver that will take an RS-232 signal, convert it into TTL, then Pulse Width Modulation would be applied, and then finally transmitted. On the reciever side, basically extracting the orignal TTL signal from the Pulse Width Modulated signal and converting it back to RS-232.
Anyone can give me some guidance about this project?
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b4bb4ge
Joined: 28 Feb 2008
Posts: 97
Helped: 15
Location: Colorado, USA
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| 15 Oct 2008 5:12 RS232 |
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very easy, you guys are over thinking this problem I have done this several times with laser diodes. you just need and MAX232 and a tx diode and rx diode (one is a photo transistor and the other a photo diode) connect these to the max232 chip through a transistor (for current reasons) and your circuit is finished.
Does this make since?
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 16 Oct 2008 3:46 Re: RS232 |
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| b4bb4ge wrote: |
very easy, you guys are over thinking this problem I have done this several times with laser diodes. you just need and MAX232 and a tx diode and rx diode (one is a photo transistor and the other a photo diode) connect these to the max232 chip through a transistor (for current reasons) and your circuit is finished.
Does this make since? |
can explain in more detail? Really need help about this.
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yupng
Joined: 16 Jul 2008
Posts: 33
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| 21 Oct 2008 8:43 Re: RS232 |
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from port rs232->max232->IR transmitter module(TX)->TR receiver module(RX).
It is work?
In MAX232 IC, there have TX and RX, so need use two IR transmitter and receiver?
MAX232 - Infrared Device
TX - RX
RX - TX
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bohumilfulin
Joined: 10 Feb 2005
Posts: 14
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| 22 Oct 2008 16:38 Re: RS232 |
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try open
http://www.connectblue.com/products/bluetooth-products/bluetooth-overview/
some of modules have rs232. Very easy to use. There is some design samples.
or try
http://www.spezial.cz/
english version
e
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