AT command for disable Radio Signal Strength Indication and alike? - gsm

Im working on a program to send and recieve SMS using a GSM modem and my computer.
I have gotten sending and receiving to work - well sort of.
Once in a while my program is sent into a total chrash due to modem is mixing up information about Radio Signal Strength Indication and alike, while also serving my program with the hex code for the message.
My code can handle the hex code just fine. but I have seen the following line popup while im decoding a byte stream:
^RSSI: 2
So far I've seen it send out values between 1 and 10.
Is there an AT Command that can disable them? I have no need for them.
Or alternative: Is there a general syntax for them, so I can filter them out before decoding?
Im leaning towards a filter solution. But that would be more easy to implement if I knew whenever modem is sending out on the form: "^SOMETHING: xxx", then It would be nice to know if it is always followed up be a delimiter say for instance "\r".

You should try turning off periodic messages as using AT^CURC=0.
Information regarding the AT^CURC command:
AT^CURC? Current setting of periodic status messages
AT^CURC=? See what you possible values are
AT^CURC=0 turn off periodic status messages

The best way to tackle this scenario would be to replace that part of the response with an empty string because otherwise, it will be difficult to check even if the command sent to disable it is working or not.
This regex will match all those. You can replace them ideally by an empty string.
(\\n|\\r|\\r\\n)\\^.*(\\n|\\r|\\r\\n)

Related

Last known value from Adafruit IO on Arduino

I'm working on a basic sketch for an Adafruit Huzzah which uses the Adafruit IO MQTT library. This is put together by copy/pasting from various sources and examples, and mostly works - but there's one thing I can't figure out.
Right now, I'm using a line of code which fires off a handler every time a new message is received via the feed I'm subscribed to:
group->onMessage("daniel", handleMessage);
This is fine, and does what I need it to do for values which are updated.
What I want to do, however, is grab the last known value on the feed during the setup() routine, rather than having to wait for a new value to come though.
In MQTT parlance, I believe this is known as retained messages, which I think Adafruit IO has on by default, but I don't know how to grab these values during the startup() process.
Can anyone help me out?
(If you're interested, here's my code so far: https://github.com/LimeBlast/family-box/blob/master/family-box.ino)
Short answer is you don't... do anything.
Retained messages are delivered just the same as normal messages (via the onMessage callback), they are just delivered as soon as you subscribe to the topic.
I also had this problem. Here is the full explination
The get() function wil ask the Adafruit servers to resend the last value of the feed to this client only. When the value is received, the handler will be executed.
exampleFeed->get();
Seeing as I've just found the answer to the question I was asking, I figured it only right I post it here.
The command I was looking for, after having setup the feed, was ->get(), as shown in this example.

SIM5216A phone functionality (CFUN) is not maintained

I'm quite new to working with Arduino/GSM and have had problems getting basic HTTP functionality working. I am currently facing multiple problems - one being that the 3G shield I am working with (SIMCOM SIM5216A) does not seem to want to connect to a carrier! :(
However, the problem I would like to focus on for this question is that Phone Functionality - designated through the AT+CFUN command - does not seem to be maintained through power cycles. Additionally, sometimes after modifying the CFUN, the modem will run a soft reset.
Here is the command I have been using to modify the phone functionality of the modem:
AT+CFUN=1,0
I am under the impression that the second parameter should stop it from running a soft reset.
I have attempted to save the AT configuration by following advice in this question's accepted answer - here is the output from power on:
START
+STIN: 25
+STIN: 25
+CPIN: READY
SMS DONE
PB DONE
AT+CFUN=1,0
OK
AT&W
OK
However, whenever I next reset, I will get the following:
AT+CFUN?
+CFUN: 4
OK
So, my question is how can I save the CFUN configuration to be consistent between power cycles? (If you happen to be able to offer advice on why I can see medium-strength signal but cannot connect to an operator network, any advice would be welcome there too, however that is not the focus of this question)
With thanks,
BadDevH.
Exactly what that is saved with AT&W is a rather muddled, see this answer for details. However, regardless of that, the AT+CFUN command is controlling such a dynamic behaviour that I cannot imagine any manufacturer ever that has saved this with &W. Think more of CFUN more like setting a fixed cruise control speed while driving a car. There is no way the car will continue with the speed from last time when started.
For normal phones the default behaviour is value 1 - full functionality - because that is the very core functionality of what they do1, but for a GSM module shield, I am guessing that the default behaviour is set to no radio in order to save power, so it stays off until you need it at which point you need to explicitly turn it on.
1
And even in the case of no sim card present, it shall still be able to make emergency calls.

How to know if you missed an incoming call in AT commands

I am using Putty to simulate my phone's modem connected via serial. When my phone receives a call it outputs 'RING' into putty but when the caller cancel the call Putty doesn't out put any response or result.
How would the modem know that the caller disconnect/cancelled the call, but not output it in putty?
Thanks
To detect missed calls you can try three things.
Check if there is a suitable AT+CIND indicator you can turn on. I do not think call will do since I assume it only goes to 1 when the call is answered. If your phone supports callsetup or something similar that should be what you need (you will have to implement logic to detect when a call does not go to state active).
For an example of enabling AT+CIND indicators, see chapter "8.57 Informative examples" in 27.007 for more explanation, and pay close attention to The subparameter order in the command is defined by the query command order, e.g.
if AT+CIND=? returns
+CIND: ("abc",(0-1)),("xyz",(0,1)),("call",(0,1))
then call is index 3, and for
+CIND: ("abc",(0-1)),("call",(0,1)),("xyz",(0,1))
call is index 2. Do not hard code any assumptions here, this should be parsed and checked run-time (one check at the beginning is enough).
Alternatively you can upon RING start polling call status with AT+CLCC until the call is no longer listed.
Or you could poll the MC phonebook storage and detect changes.
Most modems show the incoming phone number and a RING when a call is received and an END when the call is cancelled. To view the missed calls, you may use the following AT Commands.
AT+CPBS="MC"
AT+CPBR=1,99
First command tells the modem to look in the missed call phone book and the second command loads entries from 1 to 99. Note that this behavior is not standard. I was able to replicate this on a GSM module but not on my 3G modem. Try it on your modem and check if this works. All the best.

Decoding manchester code without the clock input

I'm trying to decipher messages from my smokedetectors to be able to get them connected to the system that controls the rest of the house. I've tried to decode the message myself, but from what I expected to find I cannot seem make out the different parts of information in the code.
I think I've found the bit that indicates an alarm from the smoke detector. But on the radio there is a number, which is also part of the serial number, so I expected to find this number in the transmission, but I've tried all combinations but cannot find a match. Not sure if this is even in there, but I would expect it to be used as an address for the smoke detector.
Is there some experts in this that could help me translate this the attached bit-stream just so I can check if I'm even on the right track on the decoding.
The clock signal is not available. But based on articles I've found on this subject online I'm assuming the clock-period is the same as one "long" pulse on the picture.

MBed/Arduino RS-232 Serial communication issue

I am receiving messages from a CAN interface into my mBed device. The mBed device then parses the information to send out on serial to another device. The information is sent out in the following format.
"< msg>xxxxxxxxxxxxxxxxxxx< /msg>" where x = a hex number.
The other device receiving this message will receive the information split up in half (i've accounted for this in the code). The problem I'm having is, the messages will fall into the format ..... but there are times where the format is lost, for example:
[1]xxxx< /msg>< msg>xxxxx
[2]xxxxxxxx< msg>xxxxxxx
[3]< /msg>< msg>xxxxxxxxx
[4]xxx< /msg>< msg>xxxxxx
**Please ignore the space in the msg tag, it was necessary to show on StackOverflow'**
The baud rate set 38400bps on the mBed. I'm not using any parity, stop bit, start bit etc as I'm not too familiar with how they work. Can anyone help me how I might fix this loss in format, or am I going to have to include code in the receiving device to handle this?
Many thanks in advance!
This is entirely normal, serial ports are not smart enough to recognize XML. You will have to write the code yourself. A basic algorithm is a state machine. Declare a buffer that's large enough to store a complete message. Then:
throw everything away you receive until you get '<'
store bytes you receive in the buffer until you get '>'
check that you got <msg>, back to state 1 if you did not
store bytes you receive in the buffer until you get '>'
check that you got <msg/>, back to state 1 if you did not
process the message, back to state 1
This ensures that you'll properly sync with the bus when you open the port and that you don't care how many bytes you receive in one read() call.

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