I have developed a card with sim900 and ATmel, and it works very well, but when I changed sim900 for sim800 it did not recognize the sim card.
Difference in hardware design?
SIM800,SIM800C modem operates from 3.4V to 4.4V supply range (Reduced operating range !)
SIM900, SIM900A modules operate from 3.2V to 4.8V supply range.
SIM800 is having a Pin to connect with Bluetooth Antenna
Apart from these differences the hardware design is almost similar. The same hardware circuit can be used for the SIM IC if the generated supply is within 3.4V to 4.4V for both types..
I faced this issue before. I tried to contact SIMCOM but I didn't get any response.
My solution was to give to the modem a few seconds more time to boot, before I sent any commands to it.
Even if you get an ERROR as a response when you check for the SIM card you can insist on polling the same command until a predefined timeout time.
Also, note that not all of SIM800 have a Bluetooth feature.
Which country are you currently located? SIM900A works with Dual-Band 900/ 1800 MHz. I believe it was designed for US band while SIM800C is Quad-band 850/900/1800/1900MHz and may operate world wide.
Find out the bands used by your mobile service provider and use module compatible with the band.
Related
As you probably guessed this question is not about a programming language but about arduino.
I'm making a big project which includes a GSM SIM900A module but it draws too much power.
I've looked up the datasheet but I didn't understand a lot as it references a DTR pin, something my module doesn't have.
Can someone tell me how to put it to sleep mode?
Any help will be grately appreciated!
Thanks in advance!
The GSM standard AT command for the setting of modem's level of functionality is AT+CFUN.
According to SIM900 AT commands guide its syntax is
AT+CFUN=fun[,rst]
Where:
fun: is the power saving mode
rst: is the reset flag
There are several possible values of fun parameter that can be supported or not depending on the modem vendor.
In order to reduce power consumption, SIM900A offers two possibilities:
AT+CFUN=0, means that the device is in sleep mode, and the AT interface is not accessible. Usually it keeps its network paging activities and its registration status to the network (it's not really clear from SIM900 guide). The device is woken up as soon as a wake up event occurs (for example an incoming SMS). Test it on your device.
AT+CFUN=4, that disable both TX and RX RF circuits. The AT interface remains reachable.
Usually first solution results in a bigger reduction of power consumption, but I suggest trying both of them in your specific board in order to understand what is the better choice for you.
I'm working on an Arduino Uno + ESP8266 project.
I try to use them as a web server on Wi-Fi network to control a motor that connects to Arduino - basically a trigger system that receives signals via Wi-Fi. Currently, I've successfully connected ESP8266 to my access point by sending AT commands from Arduino. Another client on the same network can statically access ESP8266's assigned IP address.
However, when I try to catch some HTTP queries (I want to use them as conditions to control the motor) I occasionally encountered the non-ASCII characters in HTTP request. I use serial comm to debug, please look at the screenshot in the link below:
Arduino - Computer serial communication for debugging
The line ",519:POST ..." should contain a complete number following "/?", but there's some strange characters instead. So I cannot determine the input data to control motor. Once in a blue moon, the expected format of request shows up as follows:
The correct data received
There's no issue with the HTTP response part, even though I got the uninterpretable request, I can still send the JSON error message back to client.
Attempt Note:
The Arduino uses different serial ports to talk to computer and ESP8266. Since the connection can be established, and the data being sent, I believe that the baud rate is simply correct on both side. (115200 for ESP8266, 9600 for computer - also tried 115200 for both and got the same result)
I use V3.3 from Arduino as power source for ESP8266. But I also use voltage regulator to smooth out the current as many people suggest that. The problem still remains.
I'm struggled with this issue for a few days, just want to know if anybody had the similar experience, or could give some clue for the next step.
After a considerable effort to stabilize the circuit, I switched to NodeMCU and got the system working perfectly. I assume that ESP8266 alone is somehow not robust enough without other components, which I unfortunately have no knowledge on.
So I'd like to close this thread with a short recommendation for anybody struggling with the same issue to switch to NodeMCU (which would replace both Arduino and ESP8266); if that could support the requirement.
Firstly, I'll just give you a brief introduction about our project... its "Speech controlled Home Automation System" where we are controlling the Home appliances by the voice or speech commands. We're successfully done with the voice recognition module. But our problem is with achieving the communication between the transmitter {where the user gives the voice command} and receiver {where the home appliances are present} through WiFi i.e. we have got 2 ESP8266 12E modules interfaced with Arduino both at the transmitter and receiver side and these two WiFi modules need to be communicated(To interchange some data sent by Arduinos).So please let us know which Arduino code need to be used at transmitter side wifi module and at Receiver side wifi module and also about the header files or additional softwares(if any)to be used.
you can achieve this by starting one of wifi modules in Access Point Mode and the other one has to be set to Station Mode in order to connect to the first one.
In case you want to add a router, just set both ESP8266 modules to Station Mode and connect them to the router.
And then transfer any data you want through AT commands of ESP8266.
Here is the refrence to them.
https://room-15.github.io/blog/2015/03/26/esp8266-at-command-reference/
If you are newbie to Esp8266 and Arduino , this will help you.
http://www.teomaragakis.com/hardware/electronics/how-to-connect-an-esp8266-to-an-arduino-uno/
Good Luck !
I worked on a similar system a year ago. I was developing a remote controlled toy. My main difference was I used the ESP8266 without an Arduino attached.
One ESP worked as a a WiFi hotspot and the other connected to it, sending messages through UDP.
For some reason, I could not get the two ESP modules to connect (I think it was a problem with the board I had), but I sent messages from my computer, and it worked out fine. I will not burden you with all of the code, but here is the GitHub link.
All that needs to happen is they will be on the same WiFi network, and then you can use the ESP8266 WiFi library to send messages between the two. Like I said above, I used UDP, which is good for high speed, with no error checking. But there is also TCP (higher up, has error checking code), or you can use the server/client part of the library to set up a full web server and read/write data to it. Without knowing what type of data, I cannot comment on what would be the best method.
As for headers, you will need WiFi.h, and if you are using UDP you will need WiFiUdp.h
You should not need any external software besides the Arduino IDE.
I taught myself from scratch for this product, using two main resources: the Arduino library reference, and the docs on the ESP8266 Arduino GitHub page
I am new to Arduino and I would like to do a project that sends data, remotely. So, the Arduino would not be connected to Wifi/Bluetooth, Ethernet, etc. Would using a GSM shield be the best way to transfer data? I do not need to make phone calls or send SMS (unless sending SMS would be a better, more reliable, option) just data to a server, who's app I would create. If this is the best option, what else would I need to make this happen? For example, on top of the GSM shield (I am looking at something cheap like this: https://www.amazon.com/Geeetech-SIMCOM-Quad-band-Development-Arduino/dp/B00A8DDYB6/ref=sr_1_2?ie=UTF8&qid=1467651878&sr=8-2&keywords=Arduino+GSM+Shield) what other charges would I need to pay? I.E. would I also need to get another phone plan? Would I have to pay for a gateway service that would receive the cell phone data and then send it to my server?
Thanks your any thoughts on this
Wifi, ethernet or GSM, it depends on what you want to use, and what you have.
With all three you can send data to a server.
There is a bench of Arduino shields. All shields from Arduino come with a library to handle communication.
Other shields from other vendors exist and they provide their libraries too.
For Ethernet you can check the arduino shield https://www.arduino.cc/en/Main/ArduinoBoardEthernet.
For Wifi there are plenty. You have first the arduino shield. You can also take a look at the CC3000. Or the famous ESP8266. For all three you can find libraries.
For GSM, Arduino has a shield and a library. Arduino uses the Quectel M10 GSM moduel. You can find lots of examples in the arduino website and all over the net (https://www.arduino.cc/en/Guide/ArduinoGSMShield).
There exist other shields like the one you mentioned. Libraries does exist for those "other" shields however they are not as maintained as the arduino one.
You need to be careful though, you'll find over Amazon (and most likely on Alibaba) some GSM modules like SIM900A that are way cheaper, those are only dual band and will work only on certain contries.
There is another cheap GSM Module called the A6. It was made by espressif the company behid the ESP8266. It's relatively new and no library exist for it at the time. You can write you own functions to use it, but that would be some extra work.
In all cases, to use a GSM module you'll need a sim card with it's phone plan and all.
Another thing to consider is how to power these shields. They use more power than an Arduino can generate (A GSM modules datasheet recommend to use a power supply that can deliver up to 2A). If you power them straight from the Arduino, you may encounter some strange behaviour.
So the ideal way is to have for them an external power supply with the required amps and have a commun ground with the Arduino.
I am trying to use GPRS functionality of the GSM/GPRS modem for sending data to the remote server but i am unable to do so.I had posted a question on Arduino Forum but didn't get any reply.Here is the link for the question.
Well my Main concern is i) I am using a GPRS/GSM Modem and i am not sure about the Power requirements of the Modem.At present i am using a 9V and 1 amp supply but the network LED on the modem is dignifying that Modem is not getting the network. So can this be because of the insufficient supply to the modem?
I very much doubt it's a power thing. Although I have limited experience with Arduino boards.
You can verify that the general GSM stuff is working by executing AT+CREG commands to check if it is connected to the mobile operator.
If you need more detailed help then I think it makes sense for you to post what AT commands are being sent to the modem. And what the modem on the firmware/software side is saying.
Below some information about dealing with GPRS and AT Commands (aka GSM stuff).
With GSM modems there are commonly three ways of getting GPRS and executing AT commands (GSM) simultaneously.
1) Inline multiplexing
As far as I am aware you can switch contexts within the AT command console. This is a little challenging when it comes to writing code. I would advise against this.
2) Mulitplexing over a single serial interface
This is done via drivers that support the GSM 27.010 specification. Some manufacturers provide MUX drivers for this purpose.
The standard command is AT+CMUX. I strongly suggest taking a look at the modem reference manual to find out exactly how to execute this command. You can get a rather information also via AT commands. By executing AT+CMUX=? to see what parameters are expected.
Effectively then you would have two serial connections open to the same serial port. One for GPRS and one for AT Commands.
Negative impact is that the performance (speed of command execution) is significantly reduced depending on how the hardware copes with it.
3) Multiplexing over multiple serial interfaces
The GSM modems that I know of provide multiple serial interfaces (UART). Therefore one can be used for executing standard AT commands. And another can be used for GPRS communications.
I'm not entirely sure if this is possible with the SIM900A. There you would have to look at the hardware information.