GSM stands for Groupe Spécial Mobile. It is a standard set developed by the European Telecommunications Standards Institute (ETSI) to describe protocols for second generation (2G) digital cellular networks used by mobile phones.

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55 views

Does an antenna work inside a plastic box

I need to put two antennas for GSM and GPS communication on my PCB. My final product will be embedded in a user-friendly plastic box with buttons, leds and switches. I have not choosed yet which type ...
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38 views

Easy-to-use Antennas for beginners

I am designing an embedded system with a GPS and a GSM modules both from the u-blox company. I need external antennas for my GSM and GPS modules. From what I see when I looked for antenna integration ...
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46 views

Relationship of antenna size to gain and directivity

This question is derived from certain answers I received for a previous question I posted. Case : Let's say I have two GSM antennas of the exact same shape, design and material. The only difference ...
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1answer
36 views

Gain vs. Directivity and effect of animal body to Antennas

My design works in a foresty area inside a collar of an elephant. These areas have at least -110dBm GSM strength (accurate ref. map linked) but, usually higher as I live in a small country where GSM ...
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36 views

mbed libraries compatibility for a GSM system

I would like to build a low-power system that can send his coordinates by SMS and also receive SMS. I choosed to go with u-blox GSM and GPS modules and I thus purchased the C027 Development board, ...
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0answers
68 views

SIM900 Error on AT Command AT+SAPBR=1,1

I intend to send some information through GET method to a php page using a SIM900 module. I tried the following sequence of commands with success. My provider doesn't require username and password for ...
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1answer
47 views

Important Parameters to Check while Chosing a GSM/GPRS Antenna [duplicate]

what technical parameters decide the performance of a GSM/GPRS antenna? (excluding power consumption and size) I have found out several antennas that have 3dBi gain. And I want to chose between them. ...
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67 views

Servo shaking when GSM module starts transmitting

I have a project which uses 2 Arduinos which is communicated with my phone by a GSM module, and that one of the Arduinos is driving two servos. The question or problem is that my servo is shaking ...
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2answers
79 views

On Computing Power Consumption for a GSM system

I'm a software student trying to learn about embedded systems. I would like to build a low-power system that can send his coordinates by SMS and also receive SMS. Unfortunately I'm at level zero in ...
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2answers
345 views

Wavelengths blocked by a certain metal mesh

Introduction: I've heard about a theory, according to which you can check if there is any leakage in your microwave oven by putting your mobile phone inside and call it. However, I gave it a try and ...
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1answer
53 views

How to provide enough current for my GSM circuit, and still use a LiOn battery?

I am very new to electronics. I am building a simple GPS tracker prototype circuit that uses a 3.7 volt 500mah lithium ion rechargeable battery. The circuit has 2 major components: a simple ...
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1answer
51 views

SIM908 POST Request

I want to send a couple of variables to a webpage in my server over the SIM908. Does anyone know how do send such data over POST protocol? I was able to complete the task using GET but currently ...
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0answers
50 views

Sim 908 AT command not working

I am working on Sim 908 GSM+GPS module. I wanted to see if it works perfectly with the PC so I connected the module with the PC and ran Realterm (a terminal software). After a lot of tries of entering ...
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1answer
96 views

Costs of microcontroller with GSM module [closed]

First of all, I have to confess that I am a noob on this topic ;) Currently I try to realize a pet project with a microcontroller, which is connected to a GSM module. I've done some research and ...
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2answers
244 views

Powering SIM 900 gsm

I bought a sim900 (the chip itself, not a module) and have gotten stuck trying to figure out how to power it. I hope to power it using a pin from my RBBB arduino clone, which outputs 5 volts and ...
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1answer
41 views

Training sequence in a GSM frame?

I was reading about the GSM frames used in GSM communication. One thing pretty unusual caught my eye. Training Sequence: This is used by the receiver’s equalizer as it estimates the transfer ...
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2answers
304 views

GPRS data call using GSM/GPRS modem (Siemens TC35 and/or MC35)

I'm developing a data aquisition module, that amongst other things, it have to comunicate through GSM/GPRS module, since it will be a mobile application. I can connect to the module and send sms's ...
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2answers
265 views

SIM908 GSM and GPS modules individual power control

I've been searching around google and even in manufacturer site for this information and found nothing relevant. Is it possible to turn off GSM module and keep turned on the GPS? How can it be done? ...
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1answer
356 views

How to Make Sure SIM900 modem will always give me +PSSUTTZ string?

I am using SIM 900 modem to enable GSM connection wirh my product. Micro-controller Communicates with SIM900 modem through a SET AT commands over UART. My product is time critical and i need to have ...
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0answers
49 views

Can't establish GPRS connection from controller command

I am posting this question out of frustration and i lost hours to figure this out. I got a GSM module that works fine and can be commanded with AT commands. When i command it from REALTERM it responds ...
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1answer
153 views

Losing sensitive data when trying to send them via GSM

I am working on a system which collects data from a set of ultrasonic sensors. Those sensors work at 40Hz frequency, and each data they send are valuable to me. I need to send those data to a mqtt ...
2
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1answer
241 views

AC/DC 4W vs 2A GSM transmission bursts

I have a big problem with the power supply of a SIM900. I designed my own board with a 220VAC-5VDC tracopower, an ARM9 CPU, and a GSM/GPRS SIM900 module. The output of the tracopower is 5V - 800 mA ...
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1answer
164 views

Receiving empty data from gprs module? [closed]

I am trying to send a string from a Huawei MU509 GPRS modem to a Linux server over the internet. I am using an AT command tester to simulate AT commands. After giving the ...
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1answer
186 views

Powering an iComSat GSM Shield and a Gear Motor with LiPo Battery

I have an iComSat GSM Arduino Shield (based on the sim900) and a gear motor that I am planning on using with a Teensy 3.1 microcontroller. I'd like to power the whole rig using a 2000mAh LiPo Battery ...
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1answer
76 views

What is the proper GPRS / GSM modem setup to work with 5 voltage sensors?

I've been looking at modems and most of them come in RS232/485 input only. I need to hook up 5 different power cables to the modem to monitor their voltage. Some of the modem's I've found have 4 to ...
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1answer
93 views

GSM module working when powered by laptop via USB but keeps restarting when powered by battery

I am using a sim900 module in the following link and I connect it to my laptop using USB to TTL converter and the module works properly. But, when I connect the same module to 9V DC battery the module ...
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1answer
280 views

GSM SIM-300 read msg problem

I'm unable to get a proper response from my GSM modem300, sometimes it responds with nothing, sometimes it replies half of line of ONE message from full inbox, sometimes it just sends the command ...
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1answer
1k views

What is the difference between SIM300, SIM900 and SIM900A

I have came across these SIM modules on an online electronic shop. My primary target is just to receive short text messages from other subscribers. But then this question about these three (if there ...
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1answer
175 views

GSM 3G VSWR and antenna testing question

I'm a recently converted SW engineer to EE (Graduated less than 3 years ago, BS in Comp Eng, focus on Digital hardware) and I've been made the hardware lead on a project here at work. The project is ...
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2answers
736 views

sim900 escape character error

I am trying to send some hex data over TCP using SIM900A module. But the sequence of data has a byte with value of 0x1B which is the escape character. As a result the module terminates the command ...
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2answers
2k views

Longest range remote control

I would like to make a long range (5Km) quadcopter. As of right now, I'm just trying to find out the best way to control it. I know that there are some 5Km R/C transmitters but they are the size of ...
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2answers
416 views

GSM vs Bluetooth shield for android to arduino communication [closed]

I need to communicate between a hacked android device and an Arduino primarily sending signals to turn on lights. No voice data. I was under the impression that Bluetooth is the best solution but ...
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1answer
98 views

Doubts related to SIM300 power rating and its configuration?

I just started reading SIM300 data sheet (http://probots.co.in/Manuals/SIM300.pdf). Under the section 5.3 Power supply ratings.I have few following doubts i) peak supply current transmission is ...
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0answers
277 views

SIM cards not responding to SIM908 module

I have a SIM908 module on a dev kit board. I have three SIM cards that are all detected fine on the previous version of the board. However, the v2 only detects one out of the three SIMs. I put the ...
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2answers
624 views

Microcontroller with integrated GSM & GPS support? [closed]

I am looking for a single chip microcontroller with GSM & GPS solution. Is there any microcontroller chip which is specifically available for GSM & GPS solution? So that it will act like ...
2
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0answers
42 views

Why is GSM interference audible? [duplicate]

We have all heard the buzzing sound that your speakers makes when you use your phone near your radio or amp. My question is why does one hear this interference if GSM operates at ~800-900MHz which is ...
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2answers
101 views

Collecting data from GSM devices

this is my first question on electronics, so I hope I will get it right. :) GSM and GPS are topics which are quite new to me, but I will try to be as clear as I can. Is it possible to collect data ...
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2answers
219 views

How to pick the right capacitor for device with significant current peaks?

I'd like to power the GPRS modem (uBlox LEON G100) with a 4V 500mA power supply. How can I calculate the capacitor parameters so that they will provide the necessary current for TX slots? The ...
2
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2answers
474 views

SIM card for SIM908 module

I just got this SIM908 dev board, and I'm trying to get it working. However, it keeps telling me "SIM not inserted": AT+CPIN? +CME ERROR: SIM not inserted which ...
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0answers
649 views

Gsm sim900 cannot read sms

I am using an arduino uno r3 with a sim900 module. I can send messages and make voice calls using https://github.com/jgarland79/GSM_Shield but I cannot read any sms messages. The getsms function ...
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1answer
499 views

How can I attach a microphone and speaker to the Arduino GSM shield?

I recently purchased the Arduino GSM shield so that I could build my own low-tech cellphone. Now that I've successfully been able to send and receive text messages, I would like to add the ability to ...
0
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1answer
2k views

Correct AT Commands sequence for Quectel M95 GSM module

I have easily managed to connect the M95 GSM module to an Arduino and can communicate. I want to have a very basic way of posting data to a website from the Arduino. It seems the AT commands are ...
21
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4answers
1k views

Is an omnidirectional antenna a must for a cell phone?

I have read somewhere (but unfortunately I am not able to remember where) that cell phones do need an omnidirectional antenna. If it is so, what are the reasons for that? Why a normal directional ...
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3answers
3k views

What AT command should be sent by modem to get time?

I am using SIM800E. I want to know what AT command should be sent by modem to get time ? This modem is having an RTC. But I need to set it automatically through cell tower. The tower can send the time ...
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1answer
526 views

netduino plus 2 compatible gps/gsm module

I have a netduino plus 2 board and I am trying to send gps location with gprs to my server.I am a java programmer by profession,but recently I got interested in IoT and m2m communications.I would like ...
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1answer
153 views

anyways to receive data from the GPS module with GSM/GPRS [closed]

Am doing a project using the GPS. the main scenario is to display the position of the object in the maps. Scenario : am plan to use a GPS Antenna in the Arduino/Netduino board. where i will code to ...
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0answers
184 views

Indoor Phone/Tablet tracking with multiple nodes

I'm looking into providing a distributed device tracking system using a number of separate nodes to detect Wifi/Bluetooth devices by their MAC addresses. (It's to power an app, not for secret ...
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2answers
498 views

GSM/GPRS AT command - hitting a link

I am trying to target a specific page (script) on my webserver using a GPRS modem. I can hit my domain, and get a reply back but then when I am trying to call my script it just won't let me: ...
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1answer
74 views

How to combine two independent estimates of location

For finding mobile location we know two methods: Trilateration of signal strength and Timing Advance. Now to improve accuracy we need to use both methods simultaneously. We are able to use both ...
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2answers
185 views

Pull signal low using a pic microcontroller

I'm working with a ADH8066 GSM Module and a PIC16F688. I want to reset the ADH8066 using the ON_KEY pin which is described as: ...