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HC-11 433MHz wireless serial module (HCMODU0054) 
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Joined: Fri Jun 05, 2015 9:32 pm
Posts: 5
Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Dear friends, another thing, let assume that from one node to another there is 10 meters and in this case there are 20 nodes. So a distance of 200 meters are being covered. If I send a message from node A to node B, and node B sends it node C and continnues to hopping from one node to another, the whole area will be covered? Just ask this to clarify


Sat Jun 06, 2015 9:14 pm
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Joined: Sun Aug 05, 2012 4:15 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Quote:
Thanks for your reply. What are the settings of at commqnd to connect the module with mcu and let both microcontrollers to talk to each others?


I'm not totally sure if I understand the question correctly but by default the modules are in communication mode. Any serial data sent to the serial pins of one module will automatically appear at the other module assuming it is on the same channel. There is additional commands required to put it into this state. If you need need to send a command to the module you have to pull pin 5 low to put it into command mode.

Quote:
another thing, let assume that from one node to another there is 10 meters and in this case there are 20 nodes. So a distance of 200 meters are being covered. If I send a message from node A to node B, and node B sends it node C and continnues to hopping from one node to another, the whole area will be covered?


What you would be creating is a very basic mesh network. This is possible. You will of course have to handle each node in range receiving the same messages multiple time because each node in its area will be retransmitting it. There are lots of ways to do this than can be implemented into your application such as routing tables, time to live counter, maximum hops counter or a unique message ID tagged onto the message. Each node will then know if it has already seen the message and not keep retransmitting it.

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Mon Jun 08, 2015 7:56 am
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Joined: Fri Jun 05, 2015 9:32 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Dear Andrew,

Really thanks for your kind help. The idea of Time to Live and Message ID is very interesting. Can you please show me how to implement the idea of Time to Live? Just the concept. Do I need to use any PIC timers?


Mon Jun 08, 2015 9:13 am
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Joined: Sun Aug 05, 2012 4:15 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
The best option depends on your system and how critical it is that a data packet gets to its destination. The time to live may not be the best option as it would require your nodes to have a synchronised network time. The best option may be to simply have a unique message ID with each packet and have each node only retransmit it once. If a node receives the packet with the same message id for a second time it will know not to retransmit it. This is just my suggestion of course and not necessary the best way to do it.

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Tue Jun 09, 2015 8:06 am
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Joined: Fri Jun 05, 2015 9:32 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Do someone knows with a remote control which is compatible with hc11 module?

Thanks


Wed Jun 10, 2015 2:52 pm
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Joined: Sat Aug 29, 2015 11:26 am
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Hi, I have just purchased three of these modules and easily managed to get them to work in default transparent mode. I have connected one to a PC and one to a laptop, both using TTL-USB adapters. What I type on the PC appears on the laptop hyperterminal and vice versa. Even sending a long text file is successful without any errors.

However I do have a problem - I cannot get the module to go into command mode. When I pull down the 'SET' pin the transmission between the two computers stops, as expected, but when I type AT and press enter I get no response. In fact nothing I do gets me any response whatsoever. By "pull-down the set pin" I mean I connect a jumper between the 'SET' pin and the ground connection.

Once I release the 'SET' pin it resumes working normally in transparent mode.

On both computers I have set
+ baud rate 9600
+ bits 8
+ parity None
+ stop bits One
+ handshaking None

Is what I described the correct way of doing it or have I misunderstood something?


Sat Aug 29, 2015 11:43 am
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Joined: Sat Aug 29, 2015 11:26 am
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Seems I sorted it out but only partly and still cannot understand what's going on.

Instead of using Hyperterminal I wrote a little program in VB6 that sends the AT commands and looks at the responses. Effectively it should be doing exactly what Hyperterminal does except that it does it automatically rather than me typing the commands manually.

At first it didn't work but then I just put a delay of 100mS after each command before sending the next and it worked fine. I then managed to set the baud rate, channel and so on.

Still cannot understand why it didn't work on Hyperterminal - surely its not the missing delay as I certainly took more than 100mS between commands when I typed them manually. Perhaps it is the opposite - maybe the characters within the command have to be sent in very quick succession?


Sat Aug 29, 2015 3:06 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
I don't have access to one until tomorrow to try them with hyperterminal but one thing to check is that when using hyperterminal you have your baud rate and settings correct and if hyperterminal is automatically terminating the AT commands with a CR or LF.

If you stilhave no luck you may want to try a different terminal program such as putty or terminal by br@y.

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Sat Aug 29, 2015 4:23 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
andrew wrote:
I don't have access to one until tomorrow
....
you may want to try a different terminal program such as putty or terminal by br@y.


Thanks Andrew.

I am guessing that the problem with hyperterminal is that it doesn't have a line mode - each character is sent as soon as a key is pressed on the keyboard. I found out that various modems and even bluetooth serial ports need all the characters in a command to be sent within less than a second and I'm guessing the HC-11 might also have that requirement.

Just before hitting the 'submit' button I realised that I could send the characters in quick succession by simply using the 'send text file' function of hyperterminal and it worked :)

The only problem was that I could only put one command in the file. If I put more I just got an 'ERROR' response from the HC-11. Eventually I sorted that out as well - there is a parameter in the 'ASCII setup' of the hyperterminal connection named 'Line Delay'. Apparently this introduces a delay after each linefeed when sending a text file. I set this to 2000mS and now it works fine. I just put all the commands in one text file and send it - the commands are sent at intervals of two seconds and I see also the responses (I also set local echo so I can see which AT command resulted in which response).

Just in case someone else comes across the same problem, maybe in the description of the command mode, where it mentions how to get into command mode, you could also add a small note with regards the characters in a command need to be sent in quick succession and that there must then be a delay between one command and another. Probably instead of an arbitrary delay one just needs to wait for the response before sending another command.

I will also try Putty as you suggested - I believe it has line mode and that should work.


Sun Aug 30, 2015 8:43 am
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Joined: Tue Mar 01, 2016 4:21 pm
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Post Re: HC-11 433MHz wireless serial module (HCMODU0054)
Hello,

I have a question related to :
"Note: Once in IO mode, to get back into command "

I have an usb HC-11 . I successfully sent the command
AT+FCSF

But now my problem is that I cannot / don't know how to make it working on UART again.
AT+FU has no effect ..
It's like it's ignoring all UART commands.

I tried to hold the pin 5 pushed and plugged it and then tried to send the command but without success.

I don't know exactly how to do, could you please help ?

Thank you very much.

Rob


Tue Mar 01, 2016 4:27 pm
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