Choosing the right gsm module for IoT

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In the vast landscape of IoT (Internet of Things), GSM modules stand out for their ability to enable communication across global cellular networks. Choosing the right GSM module for your IoT project can significantly impact the functionality and efficiency of your application, whether it’s for tracking, monitoring, or data transmission. This article delves into the […]

Evolution of GSM and 5G communication

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The evolution of mobile communications has been one of the most significant technological narratives of the past few decades. From the first generation of cellular networks to the advanced capabilities of 5G, the journey of mobile technology reshapes how we interact with the world. This article explores the progression from GSM to 5G and what […]

Low Cost Linux boards in India

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Cubie board: The Cubie board is a small board made for hardware hacking with a high end Cortex A8 ARM processor. Available for purchase locally in India. Features : 1G ARM cortex-A8 processor, NEON, VFPv3, 256KB L2 cache Mali400, OpenGL ES GPU 1GB DDR3 @480MHz HDMI 1080p Output 10/100M Ethernet, optional WiFi 4GB NAND Flash […]

Difference between Arduino and Microcontroller

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Finally came time to “shake hands” and say “Hi” to Mr. Arduino. So, here is what i came to know about Arduino, What is Arduino ? Arduino is a set of development boards that come with pre-tested hardware and software libraries. It means, you can by an Arduino board and start developing your project instantly. […]

Difference between X7R, X5R, X8R, Z5U,Y5V, X7S, C0G Capacitor dielectrics

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Ceramic capacitors are broadly categorized into 4 classes based on the dielectrics used in them, Class 1  Class 2 Class 3 Class 4  Class 3 and Class 4 capacitors are not widely used and hence have not been standardized. Class 1 Capacitors :  Class 1 capacitors  have following characteristics, Linear temperature coefficient : Their capacitance varies linearly with temperature […]

Identifying pin no 1 on an IC

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I did write to ST microelectronics support engineers, but for no avail. I did not receive any reply from them. We had ordered the part from Digikey. The datasheet showed that the pin no 1 for the SO-8 package will be identified by half circle notch but, the part i had ordered didn’t have any […]

GPS Tracker with LONG battery life – Lasts more than a year

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Requirement:  A transport company wanted to track there concrete walls which they transport all over the country and beyond. These concrete walls are loose equipment and are switched form on truck to another on trailers. So, they needed to track the wall itself instead of the truck. They were already using a 3G based GPS tracker […]

Low cost RFID readers for purchase in India

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NSK-EDK-125-TTL  NSK-125 as the name itself suggests is a low cost Low frequency(LF) RFID reader from NSK Electronics, Bangalore. Its the cheapest, as it is engineered and manufactured entirely by NSK electronics itself.  Features : LF 125KHz carrier frequency Built-in Antenna with external antenna option Supports UNIQUE and TK5530 read only transponders over the air […]

Automatic dispensing of groceries with monthly update

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Like the Yellow card for poor which allots them a certain amount of groceries like Rice, Sugar etc.  We can design a system which when entered the card number or swiped (RFID cards) will dispense the quantity of groceries allocated for that card every month. The quantity to be dispensed is maintained by a database or […]

SIM900 FTP Commands

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Watch this video if you want to see the live demo, To communicate with a web server using a FTP account we need a username and password  for logging in. In this example i am using my Linux shared hosting which i had purchased for my old company website. If you are having a cPanel […]

SIM800 series Bluetooth AT commands

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Watch this video if you want to see the live demo,   SIM800 GSM module provides a set of AT commands which can be used for Scanning devices, Pairing with them using different authentication methods, Sending and receiving data using Bluetooth SPP profile, Controlling the smartphone by using Bluetooth headset profile etc. Once you have basic […]

Arduino MQTT Library with Publish and Subscribe example

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List of my MQTT tutorials you can go through to understand the below code, Blog posts :  MQTT Protocol tutorial using Mosquitto and CloudMQTT MQTT Protocol tutorial using SIM900/SIM800 modules – MQTT over TCP Learn, How to save MQTT messages into a MySQL Database Videos :  MQTT Protocol tutorial – LIVE DEMO using Mosquitto and […]

16×2 LCD Display not working – Possible Reasons

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  Display showing black boxes: This problem tends to occur if you have chosen a very low value of the display contrast control resistor. The contrast control resistor is connected from pin#3(VEE) to pin#1(VSS/GND). This resistor value should be 4.7K ohms. Also, display may show black boxes even when you are writing the data very fast […]

SIM900 DTMF commands

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Since i have tested the below commands in the SIM900 GSM modem, I will only explain the DTMF decoding functionality with regards to SIM900. When i set out to test the inbuilt DTMF decoder in SIM900, the first thing i came to know was that the DTMF commands are not supported in all firmwares, SIM900 […]

SIM900/SIM800 Sleep mode AT Commands

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Before we begin,  It should be noted that both the sleep modes have the same current consumption and the only difference between them is the way the module enters and exits the sleep mode. Prerequisite: To enter the sleep mode the module needs to meet the following conditions,  – DTR pin is HIGH – No interrupts […]

SIM900 SMS and Call Commands

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The CALL READY message from the SIM900 indicates that the modem is powered up and has acquired a valid network. Next thing is to make sure you have set the SIM900 into TEXT mode by sending the command AT+CMGF=1; followed by a carriage return(rn). If you are facing any problem with respect to modem not […]

Learn how a heart beat sensor works

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      Doctors measure our heart rate manually. By holding our hands they feel the pulse in the nerve and look at their watch to count our heart beats per minute. Even we also can feel the pulse on our finger when our heart pumps blood into our blood vessels. This pulse is felt […]

Low cost PCB manufacturers in India

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I have listed down all the PCB manufacturers whom i came across and i have not had any real working experience with these manufacturers other than PCB Power. I didn’t need to look anywhere else PCB Power  [CSIL]:  PCB power is the only PCB manufacturer i have experience working with and i liked the transparency […]

Low cost zigbee modules for purchase in India

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We get modules that can provide RF range from 80m to 1000m and data rates of 100KBps to 1MBps. We need to choose the one best for us depending on our requirements. More the range more the cost. What are Zigbee modules: Zigbee/Xbee modules are advanced RF transceivers operating in the license free 2.4GHz frequency […]

16×4 LCD/20×4 LCD line addresses

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What i mean is, given the same circuit which was built for a 16×2 LCD display can be used with a 16×4 LCD display with no hardware changes needed at all. Even the program/code written for the 16×2 display works fine with the 16×4 LCD display except that you will only be able to display […]

GSM Network time synchronization for RTC using AT+CLTS command

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Since i had started designing the VALTRACK GPS trackers, I have always had trouble with maintaining the correct time on the tracking device because once i remove the battery, the STM32 RTC lost its synchronization. I didnt have the space or luxury to maintain a separate backup battery for the STM32 RTC.  So, i was only […]

Wireless Mobile Battery Charging system

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 Wireless charging would be a solution for our travelling-charger-forgot-pin-different problem. Even, Students used to ask me to do a project for wireless charging of a mobile battery. But i had denied them that its not possible as it would be highly energy inefficient and the solution would take huge space and include a lot of power […]

SIM900 DTMF commands

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Since i have tested the below commands in the SIM900 GSM modem, I will only explain the DTMF decoding functionality with regards to SIM900. When i set out to test the inbuilt DTMF decoder in SIM900, the first thing i came to know was that the DTMF commands are not supported in all firmwares, SIM900 […]

Career options for Electronics and Communications engineers

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  You can possibly divide the industry options for the E&C engineers into the following domains, Career in Automotive domain : Includes companies which develop electronic control units (ECU’s) for vehicles, If you end up in this domain, you will possibly be designated as a Embedded software engineer and will be developing RTOS applications for microcontrollers […]

Which mobile to buy for Android Application development?

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, 2 GB memory card. I bought this mobile for developing a application for a project which controlled Electrical appliances using Bluetooth. I used a Linvor bluetooth module which operates at +3.3V & provides a UART interface for communication with microcontroller. Linvor Bluetooth Module The microcontroller i used was PIC16F877A and the android application was […]

Learn, Why you should choose a GNSS module over a GPS module?

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There are navigation satellites launched by different countries and USA was the first one to do so. Here are some major players in the navigation space, Global Positioning System – GPS : The satellite constellation launched by USA covered the whole world and it was called the NAVSTAR and later as Global Positioning System abbreviated […]

SIM900 GPRS EMAIL AT Commands

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Watch this video if you want to see the live demo,   Before you begin make sure your SIM900 GSM module has acquired the network and it is ringing when you make a call to it. Then test the basic AT commands and then proceed further. Once you are ready, you can start by first […]

Designing a Low cost OBD II 3G/2G GPS Tracker – Part 1

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Details of the Requirement : The requirements were very simple,  The device should be able to connect to the OBD II port of any car and read data periodically and send to server via MQTT It should have 3G internet connectivity and should be able to connect to OPTUS/VODAFONE network of Australia Device should have a […]

Low cost GSM/GPRS modules for purchase in India

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1) Simcom SIM900A :  SIMCOM manufactured SIM900A is a very low cost GSM/GPRS module used widely in India for cost sensitive applications.  Features : Dual-Band 900/ 1800 MHz GPRS multi-slot class 10/8 GPRS mobile station class B Compliant to GSM phase 2/2+ Class 4 (2 W @900 MHz) Class 1 (1 W @ 1800MHz) Dimensions: […]

Foot / Palm pressure sensing and 3D plot in MATLAB

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 The 3d plot used to show the pressure distribution is a shown using the surf()  funtion of MATLAB. The plot will display pressure variations from low pressure ares with a lighter color/higher peaks and higher pressure areas with darker colors/ lower peaks. The design would involve many flat pressure sensors(FSR) distributed to form a sensor bed.   The […]

TCS230 RGB color sensor operation and Code

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Here is the image and the block diagram of the TCS230 color sensor, The first block that comes into picture is the Photodiode array. The photodiode array consists of three sets of diodes each for sensing Red, Green and Blue color respectively. So, when you are measuring the intensity of Red light you need to […]

Designing a DTMF based Home automation system – GSM | Relay control

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Recently, i got a requirement to design a audio announcement system which would play an audio every hour. So i came across a MP3 player chip and this idea crossed me that why shouldn’t i just make one multipurpose control board which would control home appliances and give audio feedback like Amazon Alexa.  So i designed this board, which can control the […]

SIM300 SMS/Call Not Working

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Click here for the SMS/CALL commands for SIM300 and verify what you are sending, SIM300 SMS Not Working: 1) Give a ring to the number/SIM which you have put in the modem and check whether its ringing or not, this way you can confirm that the MODEM is up and its getting proper network. If […]

Using Arduino with SIM900/SIM800 for receiving SMS commands

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The logic is quite simple, We just look for consecutive occurrence of commads like @C1, @C2 or CMD. Whenever the if condition is satisfied the code can take an action like turning ON or OFF a device which might be useful in building automation application for example. This code is applicable for SIM800,SIM808,SIM908,SIM800C,SIM800H,SIM900A etc all modules […]

Getting your electronics product manufactured in India

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There are 4 main stages of electronics product manufacturing, once you have completed the design with PCB gerber files, Bill of materials (BOM), and Firmware (if a processor is present): 1) Component sourcing There are a lot of electronics components distributors  in India who stock the parts locally. If you are going to get a bigger order […]

Difference between SIM800 and SIM900 GSM modules

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SIM800 vs SIM900 GSM modules There exist multiple versions of these modules,  SIM900 comes in the form of full version Quad band SIM900 & dual band version SIM900A, SIM900D  SIM800 comes in the form of full version Quad band SIM800 & stripped down compact size versions like, SIM800C, SIM800L, SIM800F etc. Each module caters to a […]

SIM900/SIM908 power supply circuit

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About the modules SIM900 is a Quad band GSM/GPRS module, which you can use for Call, SMS, GPRS functionalities, SIM908 is a Quad band GSM/GPRS/GPS combo module, which you can use for Call, SMS, GPRS, and GPS functionality. SIM908 has an inbuilt GPS which makes it useful for tracking related applications.  The image shown is a board […]

Difference between SIM900 and SIM900A GSM modems

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Since we are already very familiar with interfacing the SIM900 modem and have played around with the AT commands, the questions that come to our mind are listed below. I have tried to answer them after doing a bit web research. “What extra does SIM900 give me compared to SIM900A?” : SIM900 is a quad […]

MQTT Protocol tutorial using Mosquitto and CloudMQTT

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The MQTT protocol only defines the format of the data being transmitted and provides a pub-sub kind of communication interface between multiple devices. There are three main entities involved in MQTT, 1) Publisher : The device which publishes messages on a particular topic. 2) Subscriber : The device which receives messages by subscribing to a particular topic.  3) […]

SIM900 GPRS HTTP AT Commands

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Before you begin make sure your SIM900 GSM module has acquired the network and it is ringing when you make a call to it. Then test the basic AT commands and then proceed further. Once you are ready, you can start by first setting up the GPRS connection as follows,  Text in RED is typed […]

MQTT Protocol tutorial using SIM900/SIM800 modules – MQTT over TCP

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Free test servers for demo, Mosquitto, the creator of open source Mosquitto MQTT software also provides a free test server/broker at test.mosquitto.org, The commercial MQTT services provider CloudMQTT.com also provides free and commercial versions for users who want to test their services. Adafruit Industries also provides free and commercial versions of MQTT broker services at io.adafruit.com, They […]

Intelligent Hospital admission machine

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 The goal of the project is to design an acquisition system which increases the efficiency by automating certain procedures to measure patients body parameters. The system includes, Blood pressure measurement: A blood pressure measurement unit is provided in a booth which will automatically measure the blood pressure of the patient and log into the patients […]

Best discussion forums for Embedded systems

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your hardware and software development i suggest you guys to go ahead and register in these sites and make use of the vast pool of experience available. And the list is not extensive, readers please suggest any more sites you know so that i can add them here. You can leave suggestions in a comment or […]

Learn about the SIM800/SIM900 auto power on feature

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Why do we need auto turn on :  Let me explain why this auto turn on feature is important and where to we need this feature, Sometimes in applications where there is no microcontroller present, that time we need the GSM module to boot up by itself and start functioning. One such application is a […]

SIM868 vs SIM808 – Differences and Comparison | Which to choose?

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SIM868 is a more advanced, cheaper and smaller version with improved specs compared to SIM808 and below are the differences i observed between them,  SIM868 has DUAL SIM card interfaces : SIM808 and SIM868 are both quad band 2G modules and can work globally in 850/900/1800/1900 MHz frequency bands without any problems.  What sets SIM868 apart is […]

Started a SMT PCB assembly unit – #MakeInIndia

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Why did i buy the T-960 reflow oven? The reason i send my boards for assembling is, The parts are extremely difficult to hand solder as i use 0402 and QFN package parts in most of my designs. The 0402 parts are terrible for hand soldering as they are almost invisible and cant even be […]

SIM900/SIM800 not working – Possible reasons – Tips n Tricks

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Baud rate : You need to check at what baud rate your SIM900/SIM800 module is set to, using the command AT+IPR? . And use the same baud rate in your UART configuration. If your SIM900/SIM800 is set into auto baud mode(AT+IPR=0). Then the first AT command you send to the module from your controller should be in capital letters. […]

SIM300 GPRS commands

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Before you start accessing internet on SIM300 you need to make sure that, Internet service is active on your SIM card. The APN, username, password for accessing internet, It depends on your network operator, for vodafone and airtel the APN is “www” and username and password are blank. ( not sure about other networks) You […]

Low cost 3G modules for using in Australia | UMTS/HSDPA modems

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Australia has completely shutdown 2G networks: Since the advent of the shutdown of 2G networks, All the Australian network providers have completely migrated to 4G networks, with 3G fallback wherever 4G is not available. USA was the first to announce the shutdown of 2G networks but they are still using 2G networks and even Europe […]

Google wallet not accepting debit cards

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When i entered the credit card number 52 Rs was charged automatically. I don’t know the reason. The card which worked was HDFC bank Credit card (Master card enabled). I wanted to register as an android developer and create an Android developer account on Google play to sell Android applications. So it required to pay […]

Difference between SIM908 vs SIM808 modules

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SIM908 vs SIM808 GSM,GPS,GNSS modules SIM908 is a quad band module and comes in a 30mm x 30mm LCC package with simple GSM and GPS functionality SIM808 is a quad band module and comes in a smaller 24mm x 24mm LCC package with GSM, More sensitive GNSS, Bluetooth, F.M, Audio recording functionality.   The common questions that come to […]

Designing a NBIOT/LTE CAT-M1 GPS tracker for Google Cloud IOT Platform

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In this post i want to share about the new LTE-CAT-M1 and NBIOT enabled GPS tracker we designed for the UK market. This device is based on the VALTRACK-V2B device and has everything similar except few changes. This device was designed based on a clients requirement who needed the GPS tracker to connect to Google Cloud IOT Platform by […]

Learn how to update the firmware of your SIM800 modules

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Pre-requisites :  First download the tools, files and documents used for the firmware update from the below links, SIM800 series firmware update tool  SIM800 Firmware upgrade Application note Bluetooth enabled firmware for SIM800C Firmware update methods: We can program a new firmware image to our SIM800 module using either UART interface or USB interface.  USB […]

Using SIM900 as TCP server ? – Read this first !!

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SIM900 supports TCP communication in both client mode and server mode. Client mode is straight forward and you can see the tutorial at this link, https://youtube.com/playlist?list=PL6peP1Mv7tr9SwnGYfLsweYuuE9COKG9H   How to get SIM900 running as a TCP server? Now if you want to use SIM900 as TCP server you need to get its Public IP address and […]

Google Speech Recognition HTTP API – Tutorial with Live Demo .. !

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Convert to Audio Formats accepted by Google :  For the demonstration, I had recorded some audio on my phone and converted them to FLAC format and LINEAR PCM 16bit format for sending to the API. For converting the audio to FLAC format i used this online tool – CONVERT TO FLAC For converting the audio to LINEAR16 format i […]

Difference between SIM5320 and SIM5360 modules

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SIM5360 is a more advanced version of SIM5320 and below are the differences i observed between them,  Network connectivity : SIM5320 is a Dual band HSDPA module and can provide data download speeds upto 3.6Mbps. SIM5360 is a Dual band UMTS/HSPA+ module and can provide data download speeds upto a whopping 14.4Mbps. Both modules support […]

Cadence SPB 16.5 installation error

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  Right click on Mycomputer->Properties->Advanced System Settings Environment variables    User variables for Windows 7  Variable                    Value CDS_LIC_FILE         C:CadenceLicenseManagerlicense.dat LM_LICENSE_FILE       5280@sony-VAIO;C:CadenceLicenseManagerlicense.dat   System variables   CDS_LIC_FILE         5280@sony-VAIO;C:CadenceLicenseManagerlicense.dat CDS_LIC_ONLY       1 LM_LICENSE_FILE   5280@sony-VAIO;C:CadenceLicenseManagerlicense.dat

Designing a Low cost NBIOT GPS tracking device – VALTRACK-NBIOT

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This is an update post on the miniature GPS tracking device VALTRACK-NBIOT designed for NBIOT network operation. This device is based on VALTRACK-V2 GPS Tracker and very closely resembles it. The functionalities also remain same except that it operates on the LTE NBIOT network compared to the 2G based VALTRACK-V2. Size : The form factor remains […]

SIM900 GPRS HTTP AT Commands – Page 2 of 2

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 Uploading a file to the server using HTTP POST We will upload a file to the server using HTTP POST multipart/form-data method. You can search in google for more information on multipart/form-data method of sending data in HTTP POST. In this method the POST variables are sent between demarcation strings called boundary. The server will be […]

SIM900 & SIM908 GSM module – Autobaud rate [Solution]

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SIM300 GSM module had the default baud rate set to 9600 bps, and as soon as you power on the modem you will be able to communicate with the module only at a fixed baud rate of 9600 bps (Ofcourse baud rate could be changed later). SIM900/SIM908 GSM modules on the other hand have autobaud mode enabled, […]

Low cost and long range RF module-1200 meter/1.2km in India

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The module is available for purchase in India at a price as low as Rs.900 /-.  I am talking about the MRF24J40 zigbee transceiver based MRF24J40MB 2.4GHz long range RF module with onboard antenna, power amplifier and a SPI interface for communication with the microcontroller. The details of the module are given below, Microchips MRF24J40MB: The […]

Geo-tagging for retreiving of location information

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In addition to the latitude and longitude values of the location, altitude and the direction in which the photo or video was shot can also be added. The concept can be implemented as follows, Capture device or Camera: First of all we will need a camera which will capture a picture or video. The camera […]

Don’t use SIM900,SIM908,SIM800,SIM808 modules in USA (2G sunset)

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SIM900 and SIM800 family GSM/GPRS modules from SIMCOM are the low cost,well documented and most widely used modules across the world including USA. These devices have gained popularity among the student, hobbyist community over time after taking over from their predecessor SIM300 which made the GSM M2M market access easier to beginners in Embedded systems […]

Designing a 3G Foaling Alarm and GPS tracker

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The design requirements :  Originally this device was intended to be a foaling alarm prototype with a GPS tracking option to be used in Australia. Foaling alarm is a device used to detect and alert the horse owner when the horse is about to give birth to a baby so that the owner can take […]

Using Arduino with SIM900/SIM800 for receiving SMS commands

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The logic is quite simple, We just look for consecutive occurrence of commads like @C1, @C2 or CMD. Whenever the if condition is satisfied the code can take an action like turning ON or OFF a device which might be useful in building automation application for example. This code is applicable for SIM800,SIM808,SIM908,SIM800C,SIM800H,SIM900A etc all modules […]

Conveyer belt automatic bifurcation system

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 The motor controlling the belt movement will be controlled by a microcontroller. The micro-controller reads the color information or the card number incase a RFID is used and controls a bifurcation mechanics which will be either a moving robot arm for pushing the object to a tray or doing a pick and place operation. The color can […]

I Imported a Original PRUSA i3 MK3 3D Printer Kit to India

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This post is regarding the 3D printer i purchased recently from Prusa Printers from Czech Republic. I imported their latest version Original Prusa i3 MK3 to India. Since the printer is a little expensive, i had to pay a large amount as customs duty for the import. Now lets get into the details. Why i bought […]