LTE CAT-M + NB-IoT Shield for Arduino




About: I'm a young engineer with a passion for DIY and electronics! Learn to share, share to learn!

Intro: LTE CAT-M + NB-IoT Shield for Arduino


The LTE/NB-IoT shield uses SIMCOM's SIM7000-series cellular modules, which are low-power 4G LTE/NB-IoT modules that support the new LTE CAT-M and NB-IoT technology and also have integrated GNSS (GPS, GLONASS and BeiDou/Compass, Galileo, QZSS standards) for location tracking. There are multiple SIM7000-series modules that cater to different regions around the world, and luckily SIMCOM has made it really easy to identify: SIM7000A (American), SIM7000E (European), and SIM7000C (Chinese). Currently NB-IoT is supported in many countries around the world but unfortunately not in the US, although it's scheduled to be launched by major providers by 2018 and we can still use the LTE CAT-M functionalities!

To use the LTE Shield, simply plug the shield into an Arduino, insert a compatible SIM card, attach the LTE/GNSS antenna, and you're good to go!


With the emergence of low-power IoT devices with cellular connectivity and the phase-out of 2G (with only T-mobile supporting 2G/GSM until 2020), everything is moving toward LTE and this has left many people scrambling to find better solutions. However, this has also left many hobbyists facepalming with legacy 2G technology like the SIM800-series modules from SIMCOM. Although these 2G and 3G modules are a great starting point, it's time to move forward and SIMCOM recently announced their new SIM7000A LTE CAT-M module at a developer's conference. How exciting! :)

The amazing part of all of this is that SIMCOM made it extremely easy to migrate from their 2G and 3G modules to this new module! The SIM7000-series use many of the same AT commands which minimizes the software development by miles! Also, Adafruit already has a wonderful FONA library on Github that can be used to introduce this new SIM7000 into the party!

What is LTE CAT-M?

LTE CAT-M1 is considered the second-generation LTE technology and is lower-power and more suitable for IoT devices. NarrowBand IoT (NB-IoT) or "CAT-M2" technology is a Low-Power Wide Area Network (LPWAN) technology specifically designed for low-power IoT devices. It is a relatively new technology that is, unfortunately, not yet available in the US, although companies are working on testing and building the infrastructure. For IoT devices using radio technology (RF) there are several things to keep in mind: Power consumptionBandwidthRangePacket size (send lots of dataCostEach of these have tradeoffs (and I won't really explain them all); for example, large bandwidth allows devices to send lots of data (like your phone, which can stream YouTube!) but this also means it's very power-hungry. Increasing the range (the "area" of the network) also increase power consumption. In the case of NB-IoT, cutting down the bandwidth means that you won't be able to send much data, but for IoT devices shooting morsels of data to the cloud this is perfect! Hence, "narrow"-band technology, ideal for low-power devices with little amounts of data but still with long range (wide area)!

The LTE/NB-IoT Shield for Arduino

The LTE shield that I've designed uses the SIM7000-series to enable users to have extremely low-power LTE CAT-M technology and GNSS at the tip of their fingers! The shield also sports a high-accuracy MCP9808 I2C temperature sensor, great for at least measuring something and sending it via LTE! Currently I am using the SIM7000A because I am in the US, but unfortunately we poor souls don't have NB-IoT here yet. However, for those in other places of the world it's as easy as swapping out the SIM7000A with other versions like the SIM7000E and SIM7000C modules.

Since I'm a huge fan of open-source (as you can see from my Reflowduino project) I've made this project completely open-source as well, with special thanks to Adafruit for their FONA library! (And if they'd allow it, I'd call this the "FONA LTE" but I'm not making that official due to copyright purposes lol). You can view all the schematics, EAGLE PCB files, Arduino code, and detailed wiki on the LTE shield Github page!

Step 1: Gather Parts

Below is a list of all the parts you will need:

  • Arduino or Arduino-compatible board - The Arduino Uno is the most common choice for this! If you want to use the LTE shield as really a "shield" you should use an Arduino board with the Arduino form factor. Stating the obvious, you will also need a programming cable to upload Arduino sketches to the board!
  • LTE/NB-IoT shield - The shield comes with a dual LTE/GPS uFL antenna and stacking female headers! The board comes in three different versions (SIM7000A/SIM7000C/SIM7000E) and depending on which country you live in you will need to select the right version. I've created this page on the Github wiki that shows you how to find out what version is best for you!
  • LTE CAT-M or NB-IoT SIM Card - Although the kit no longer includes a free SIM card, you can pick up a Hologram SIM card which gives you 1MB per month for free and works practically anywhere in the world because Hologram has partnered up with over 500 carriers! They also have pay-as-you-go and monthly plans and have a great community forum for technical support on SIM card activation, Hologram APIs, and more! It works great with this shield nation-wide in the USA for AT&T and Verizon's LTE CAT-M1 networks but note that in other countries you may have to get your own SIM card from a local provider since Hologram partners up with carriers and CAT-M and NB-IoT is relatively new.
  • 3.7V LiPo Battery (>1000mAH): While searching for networks or transmitting data the shield can draw significant amounts of current so it's best to not rely on direct power from the Arduino 5V rail. Instead, plug in a 3.7V LiPo battery into the JST connector on the board and make sure the battery is wired with the positive wire on the left (like those found at Sparkfun or Adafruit). Also, it's important to make sure that the battery must have at least 500mAH capacity (bare minimum) to be able to supply enough current and prevent the module from rebooting during current spikes. 1000mAH or greater is recommended for stability. The reason for this bare minimum capacity is because the LiPo battery charging circuitry is set to 500mA so you should make sure that the battery is at least 500mAH capacity to prevent damage to the battery.

Step 2: Assemble the Shield

In order to use the shield you will need to solder headers onto it unless you don't plan on using this board as a "shield" and more of a standalone module instead, which is also perfectly OK! An example of doing this is using an Arduino Micro as the controller and wiring it up to the LTE module separately.

The most common choice for using the board as an Arduino shield are stacking female headers, which are included with the LTE shield. After soldering the headers, go ahead and place the shield on top of the Arduino board (unless you're using it as a standalone board) and you're ready for the next step!

Note: For tips on how to solder the pins you can visit this page of the Github wiki.

Step 3: Shield Pinouts

The LTE/NB-IoT shield simply uses the Arduino's pinout but connects certain pins for specific purposes. These pins can be summarized below:

  • EN - Note: This was only on revision v4. This pin controls the voltage regulator on/off when pulled high/low by an Arduino pin. This pin isn't normally connected on the Arduino so you will have to wire it up separately with a jumper wire. You can also cut the "EN" trace next to the pin to disable the pull-up resistor on the EN pin to minimize parasitic current (about 33uA) through the resistor when the EN pin is pulled low. However, if you cut the trace the SIM7000 won't turn on until the Arduino sets the EN pin high.
  • VBAT - This is directly tied to the LiPo battery's positive terminal and is also the voltage supply to the SIM7000 module. On the Arduino this pin is normally not connected to anything so you are free to use it as you wish! It can be a handy pin for convenience or for analytics. If you are using a LiPo battery and would like to monitor the battery charge, please see the "b" command in the "LTE_Demo" code (in a later section in this tutorial)
  • D6 - Connected to the SIM7000's PWRKEY pin
  • D7 - SIM7000's Reset pin (only use this in case of emergency reset!)
  • D8 - UART Data Terminal Ready (DTR) pin. This can be used to wake the module from sleep when using the "AT+CSCLK" command
  • D9 - Ring Indicator (RI) pin
  • D10 - UART Transmit (TX) pin of the SIM7000 (this means you should connect the Arduino's TX to this!)
  • D11 - UART Receive (RX) pin of the SIM7000 (connect to Arduino's TX pin)
  • D12 - Good 'ole D12 on the Arduino, BUT you can connect it to the ALERT interrupt pin of the temperature sensor by soldering a jumper
  • SDA/SCL - The temperature sensor is connected to the shield via I2C

If you are using the board as a standalone module and not as a "shield" you will need to connect the necessary pins AND the 5V and GND pins. Below is a list of the bare minimum requirements for using the SIM7000 module with another microcontroller:

  • GND (the logic needs a reference!)
  • 5V (the SIM7000 runs on 3.6V so you should supply at least 4V or so to be safe, but less than 6V!)
  • D6 / PWRKEY (this turns on the shield!)
  • D10 / SIM7000 TX (TX and RX are for sending AT commands and receiving replies!)
  • D11 / SIM7000 RX
  • SDA/SCL (if you want to use the temperature sensor)

However, if all you need is to test AT commands, then you only need to connect 5V and GND as well as the micro USB cable, then follow these procedures to test AT commands (Note: currently only works on Windows)

It should also be noted that on the next version there will be the option of supplying a custom logic voltage anywhere from 1.8V to 5.5V for the voltage translator rather than using default 5V logic.

For detailed information about the shield pinouts and what each pin does, visit this Github wiki page.

Step 4: Powering the Shield

To power the shield, simply plug in the Arduino and the shield will derive its power from the 5V power rail on the Arduino. However, you will also need a 3.7V LiPo battery (1000mAH or greater capacity) like the ones sold at Adafruit or Sparkfun, especially if you're using the SIM7000E, SIM7000C, or SIM7000G versions which support power-hungry GSM. Without the battery you will likely see the module boot up then crash shortly thereafter.

You can still power the Arduino as you normally would via the USB cable or externally by a 7-12V power source on the VIN pin and the 5V rail on the Arduino will charge the LiPo battery. Note that if you are using a standard Arduino board you can safely power it via an external power source while also keeping the programming cable plugged in because it has voltage-selection circuitry.

LED Indication

At first you might be wondering if the board is even alive because there maybe not be any LED's turning on. This is because the "PWR" LED is a power indicator for the SIM7000 module itself, and although you are supplying power you haven't turned the module on yet! This is done by pulsing the PWRKEY low for at least 72ms, which I'll explain later. Also, if you have a battery connected and it's not fully-charged yet the green "DONE" LED won't turn on, but if you don't have a battery connected this LED should turn on (and might flash occasionally when it's tricked into thinking the nonexistent battery isn't fully-charged due to slight voltage drops).

Now that you know how to power everything let's move on to the cellular stuff!

Step 5: SIM Card & Antenna

Choosing a SIM Card

Again, your SIM card needs to be able to support LTE and it has to be a "micro" SIM. You can use any LTE SIM card that you would normally use on a smartphone but usually those involve a contract of some sort. However, you can also get a prepaid SIM card but the drawback is that you only really have the option of choosing unlimited data/text/voice for somewhere around $40/month.

Perhaps the best option for testing is the Hologram Developer SIM card (now included for free in the SIM7000 shield kit) which provides 1MB/month for free and access to Hologram's APIs and resources! Simply log on to your dashboard and enter the SIM's CCID number to activate it, then set the APN settings in the code (explained later). It is hassle-free and works anywhere in the world because Hologram supports over 200 carriers globally!

Inserting the SIM Card

First of all you should make have to break the micro SIM out of the normally-sized SIM card holder. On the LTE shield locate the SIM card holder on the left side of the board near the battery connector. The SIM card is inserted into this holder with the SIM's metal contacts facing down and the little notch on one edge facing the SIM card holder.

Antenna Goodness

The LTE/NB-IoT shield comes with a really convenient antenna because it integrates both cellular and GPS antennae in a single piece! It's also flexible (although you shouldn't try to twist and bend it a lot because you might break the antenna wires off the antenna if you're not careful) and has a peel-away adhesive on the bottom for you to stick it onto things! Connecting the wires is super simple: just take the wires and snap them onto the matching uFL connectors on the right edge of the LTE shield. NOTE: Make sure you match up the LTE wire on the antenna to the LTE connector on the shield, and the same with the GPS wire because they're criss-crossed!

Step 6: Arduino IDE Setup

This LTE/NB-IoT shield is based on the Adafruit FONA boards and uses the same library but improved with added LTE support. You can read full instructions on how to install my revised FONA library here on my Github page.

You can also see how to test out the MCP9808 temperature sensor by following these instructions, but here I'll mainly be focusing on the cellular stuff!

Step 7: Arduino Example

Baud Rate Setup

By default the SIM7000 runs at 115200 baud but this is too fast for software serial to reliably operate on and characters might randomly appear as square boxes or other odd symbols (for example, an "A" could show as "@"). In order to fix this I've added baud rate setup in the setup() function of the example sketches that starts at 115200 (default baud) then configures the module to 4800 baud. Unfortunately the module seems not to remember the new baud rate setting if it's powered off then back on, but that's OK since it always resets to 115200 and we can easily set it back to a lower rate. If you didn't power cycle the device you can bypass waiting for the initialization at 115200 baud to scroll through the serial monitor simply by pressing the reset button on the Arduino. This usually will power cycle the SIM7000 as well, making it reset to 115200 so that the Arduino immediately finds it.

Update: Apparently users of the SIM7000E have indicated that the baud rate actually is permanent, even after power cycling. If you happen to have a module like this, then go you! You can simply comment out the 115200 baud rate stuff after initializing the baud rate the first time.

Note that if you are using hardware serial (like if you are externally wiring the SIM7000 board to another board) you most likely won't have to deal with the baud rate reset issue since you can simply use the default 115200. However, it's good just to be aware of this! Also, hats off to anyone who can figure out why the module won't retain the baud rate setting!

LTE Shield Demo

Next follow these instructions to open the "LTE_Demo" sketch. If you scroll down to the end of the "setup()" function you will see a line "fona.setGPRSNetworkSettings(F("hologram"));" which sets the APN for the Hologram SIM card. This is absolutely needed, and if you are using a different SIM card you should first consult the card's documentation on what the APN is.

When the code runs the Arduino will attempt to communicate with the SIM7000 via UART (TX/RX) using SoftwareSerial. In order to do this, of course, the SIM7000 has to be powered on, so while it's trying to establish a connection, check for the "PWR" LED to make sure it turns on! (Note: it should turn on about 4s or so after the code runs). After the Arduino successfully establishes communication with the module you should see a large menu with a bunch of actions the module can perform! However, note that some of these are for SIMCOM's other 2G or 3G modules so not ALL of the commands are applicable to the SIM7000 but lots of them are! Simply type the letter corresponding to an action you want to perform and click "Send" at the top right of the serial monitor or simply press the Enter key. Watch in amazement as the shield spits back a reply!

Demo Commands

Below are some commands you should run to make sure your module is set up before proceeding:

  • Type "n" and press enter to check the network registration. You should see "Registered (home)". If not, check if your antenna is attached and you may also have to run the command "G" (explained below) first!
  • Check the network signal strength by entering "i". You should get an RSSI value; the higher this value the better! Mine was 31, which indicates the best signal strength bracket!
  • Enter the command "1" to check some really cool network info. You can get the current connection mode, carrier name, band, etc.
  • If you have a battery connected, try the "b" command to read the battery voltage and percentage. If you're not using a battery this will command will always read around 4200mV and therefore say it's 100% charged.
  • Now enter "G" to enable GPRS. This sets the APN and is crucial for getting your device connected to the web! If you see "ERROR" try turning GPRS off by using "g" then try again. If you're not using GPRS then you can open Adafruit_FONA.cpp and go to the "enableGPRS" function at line 1168 (approx) and uncomment the if statements that automatically determines if you're using an LTE module and will eliminate unnecessary AT commands. Save the file and re-upload the sketch.
  • To test if you can actually do something with your module, enter "w". It will prompt you to enter the URL of the webpage you want to read, and copy/paste the example URL "" and press enter. Shortly thereafter it should give you a message like "{"this":"failed","with":404,"because":"we couldn't find this"}" (assuming no one posted data for "sim7000test123")
  • Now let's test sending dummy data to, a free cloud API by entering "2" in the serial monitor. You should see it run through some AT commands.
  • To test if the data really got through, try "w" again and this time enter "{deviceID}" without the brackets, where the device ID is the IMEI number of your device which should be printed at the very top of the serial monitor from the module initialization. You should see "succeeded" and a JSON response containing the data that you had just sent! (Note that the 87% battery is just a dummy number that is set in the code and may not be your actual battery level)
  • Now it's time to test the GPS! Enable power to the GPS using "O"
  • Enter "L" to query the location data. Note that you might have to wait around 7-10s before it will get a fix on the location. You can keep entering "L" until it shows you some data!
  • Once it gives you data, copy and paste it into Microsoft Word or a text editor so that it's easier to read. You will see that the third number (the numbers are separated by commas) is the date and time, and the next three numbers are the latitude, longitude, and elevation (in meters) of your location! To check if it was accurate, go to this online tool and search your current location. It should give you the lat/long and altitude and compare these values with the one your GPS gave!
  • If you don't need GPS you can turn it off using "o"
  • Have fun with the other commands and check out the example "IoT_Example" sketch for a cool example on how to send data to a free cloud API via LTE!

Send & Receive Texts!

To see how to send texts from the shield directly to any phone and send texts to the shield via Hologram's Dashboard or API, please read this Github wiki page.

IoT Example: GPS Tracking!

Once you verify everything is working as expected, open the "IoT_Example" sketch. This example code sends GPS location and bearing data, temperature, and battery level to the cloud! Upload the code and watch in amazement as the LTE shield does its magic! To check if the data was really sent to the cloud, go to "{IMEI}" in any browser (fill in the IMEI number found at the top of the serial monitor after module initialization, or printed on your SIMCOM module) and you should see the data that your device sent!

With this example you can also uncomment the line with "#define samplingRate 30" to send data repeatedly instead of only running once. This makes your device essentially a GPS tracking device!

For more details, please visit the tutorials I made for real-time GPS tracking:


For common questions and troubleshooting issues please visit the FAQ on Github.

Step 8: Testing With AT Commands

If you would like to test your module with AT commands an easy way is to use the "AT_Command_Test" example sketch which you can find in the LTE examples folder on Github. This sketch allows you to enter commands into the serial monitor and prints the response of the module. This way you can freely experiment with AT commands to your heart's content! I've also added a function for toggling the power of the module, resetting the module, and changing the baud rate!

NOTE: Perhaps an easier method (for Windows users) is to install the Windows drivers detailed in this tutorial and test AT commands by using the shield's micro USB port instead!

If you still want to experiment with the AT commands but want to run them in a sequence and don't want to mess with altering the FONA library you can do that with a simple little library I wrote called the "AT Command Library" which you can find here on Github. All you need to do is download the ZIP from the repository and extract it into your Arduino libraries folder and an example sketch (called "AT_Command_Test.ino") for the SIM7000 can be found here in the LTE shield Github repo. This library allows you to send AT commands via Software Serial with timeouts, checks for a specific reply from the module, neither, or both!

Testing Network Connection

Here is a list of some AT commands that might be helpful to make sure your module is really connecting to the LTE network:

  • First type in "AT" to make sure that your module is communicating. You should receive an "OK" reply.
  • Next enter "AT+CREG?" to see the network registration. What you want to see is "+CREG: 0,1"
  • Next type in "AT+CPSI?" to see the network you're connected to. It should be either LTE CAT-M1 or LTE CAT-NB! If it's connected to either of these, you're good to go!
  • You can also try "AT+COPS?" to see the name of the carrier. For my Hologram SIM card I got "Verizon Wireless Hologram"

Step 9: Current Consumption

For IoT devices, you want to see these numbers to go way down, so let's take a look at some of the tech specs! Note: All these are based on the attached SIM7000 Hardware Design document so I'm only going to attempt to summarize the really important stuff!

  • Power Down Mode: You can use the "fona.powerDown()" function to completely power off the SIM7000. The SIM7000 hardware documentation says that this mode essentially shuts down the module's power supply entirely, but the SIM7000 spec overview document says it draws 7uA and I have yet to test that. Shortly after you turn off the module the "PWR" LED should turn off.
  • Power Saving Mode (PSM): This mode gives the most power savings (at only 9uA) while still keeping the module powered. In this mode only the RTC's power will be active. For those ESP8266 fans out there, it's basically "ESP.deepSleep()" and the RTC timer can wake up the module. Maybe I'll write some Arduino functions and post a followup tutorial on how to use this if I get a chance to play with it!
  • Flight Mode: In this mode power is still supplied to the module but RF is completely disabled but the SIM card is still active as well as UART and USB interface. You can enter this mode using "AT+CFUN=4".
  • Minimum Functionality Mode: This mode is the same as Flight Mode except the SIM card interface is inaccessible. You can enter this mode using "AT+CFUN=0" but you can also enter this mode using "AT+CSCLK=1" after which the SIM7000 will pull up the DTR pin when the module is in idle mode. In this sleep mode pulling DTR low will wake up the module. This can be handy because waking it up can be a lot faster than powering it up from scratch!
  • Discontinuous Reception/Transmission (DRX/DTX) Mode: The hardware datasheet also seems to indicate that you can configure the module to receive or transmit on a routine basis but not continuously, although I couldn't find documentation on this.
  • Disable "PWR" LED: To save a few more pennies you can disable the module's power LED by cutting the normally-closed solder jumper next to it. If later you change your mind and want it back, just solder the jumper!
  • "NETLIGHT" LED On/Off: You can also use "AT+CNETLIGHT" to turn off the blue network status LED completely if you don't need it!
  • GNSS On/Off: You can save 30mA by turning off GPS using the command "fona.enableGPS()" with true or false as the input parameter. If you're not using it I'd suggest you to turn it off! Also, I found that it only takes about 20s to get a fix on location from a cold start and only about 2s when the device has already been on (like if you turn GPS off then back on and query again), which is pretty fast! You can also experiment with warm/hot start and assisted GPS.

Step 10: Conclusions

Overall, the LTE/NB-IoT shield is super fast and uses cutting-edge technology with integrated GPS and comes loaded with cool features! Unfortunately for those of us in the United States, NB-IoT is not fully deployed here so we will have to wait until next year or later, but with this LTE shield we can still use LTE CAT-M1 which is also geared toward IoT devices. This shield is great for experimenting with low-power cellular devices like GPS trackers, remote dataloggers, and much more! By including other shields and modules for things like SD card storage, solar panels, sensors, and other wireless connectivity, the possibilities are almost endless!

  • If you liked this project, please give it a heart and vote for it!
  • If you have any comments, suggestions, or questions, feel free to post it below!
  • To order your own shield, please visit my website
  • Check out my Indiegogo campaign for this shield!
  • As always, please share this project!

I've launched an Indiegogo campaign taking pre-orders to help manufacture and get these shields into the hands of users. I'm also developing shields for different applications, including high-speed LTE with modules that support all sorts of really cool stuff. Furthermore, I'm planning on adding support for the other features of the SIM7000 including SSL, FTP, PPP, NTP time sync, etc. and I'll try to investigate the nitty-gritty of the power saving techniques for the SIM7000, writing custom functions in Arduino IDE. Maybe I'll post another tutorial on exactly how to use them!

With that said, happy DIY'ing and make sure to share your projects and improvements with everyone!

~ Tim



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    25 Discussions


    6 days ago

    Hi I have spend many hours trying to get the SIM700 let shield to work with my arduino mega without any access following your code step by step

    the error i am currently getting is

    LTE_Demo:98:3: error: 'Adafruit_FONA_LTE' does not name a type

    I would really appreciate some guidance

    I have a 4G sim card in shield

    I am wanting to be able to get current location from the board so that i can then build a geo fence application.

    I am happy to communicate live via skye if possible my skype name is TrackingCentral or you can email me at

    PS when i use the standard card that comes in the DFRobot library for this shield the serial monitor stops at Turn On SIM7000.....

    7 replies

    Reply 5 days ago

    i have followed your instructions and still get same error

    Adafruit_FONA_LTE fona = Adafruit_FONA_LTE();

    this is crazy i buy a shield then have to spend many hours for several days trying to get it to perform basic functions


    Reply 5 days ago

    And are you using the Botletics SIM7000 shield or some other hardware? I don't see your name/email/country matching any of my orders so I just want to confirm.


    Reply 5 days ago

    Sorry you're having problems with it. I'll email you so we can communicate better. Many people are using the shield without any problems. I think it's just a setup issue where you might have an old conflicting FONA library in there somewhere.


    Reply 6 days ago

    You should also use a Hologram SIM card or another AT&T or Verizon LTE CAT-M1 enabled SIM card. Traditional LTE SIM cards won't work.


    Reply 5 days ago


    I am in Australia, are you telling me that I cannot use a 3/4g lte sim from Australia in this board ???


    Reply 5 days ago

    That is correct. If you're in Australia you should be using Telstra's LTE CAT-M or NB-IoT SIM card. The SIM7000E module only supports LTE CAT-M, NB-IoT, and has 2G/2.5G fallback if needed, so you should use GSM if you wanted but that's not the main point of the module so I suggest getting an appropriate SIM card :)


    23 days ago

    Great. I noticed it's GPS ..can this be modified for GPS free using LTE TDOA .. If not I assume the battery would still last 5 years if I say enable GPS on demand to send coordinate every 30 mins or an hour?

    2 replies

    Reply 23 days ago

    So apparently the SIM7000 uses the cell tower for assisted GPS but does not support standalone TDOA. Hope that helps!


    Reply 23 days ago

    That's a great question! I'm finding out right now from SIMCom, hopefully I get a reply.


    6 weeks ago

    How to integrate with firebase, https post


    Question 5 months ago on Introduction

    Can I use this GMS module to send pictures to a website.

    Or can you prescribe any GMS module that I can be commanded by an arduino to send adrucam pictures to a website.

    1 more answer

    Answer 6 months ago

    I cannot really guarantee if the LTE CAT-M1 and NB-IoT will work in Sri Lanka since I don't know enough about the available networks there, but GSM should work there.


    Question 7 months ago on Step 10

    Hi Tim, I'm working on an application where we would like to be able to send 100 kB blocks of data over the modem quickly and regularly with power saving mode in between transmits. It seems that using the Software Serial @ 4800 bps would be a bottleneck here. There's a comment in the IoT_Demo sketch that using the hardware serial is possible. Is that viable with this shield? What would be involved? Thanks!

    1 more answer

    Answer 7 months ago

    Yep you can certainly use hardware serial on this shield. The only thing you would need to do is uncomment the hardware serial part of it and wire up the shield externally. The pins you will need are TX/RX (hardware serial pins on the MCU), 5V/GND pins, and I2C if you need the temperature sensor. Note that the IoT_Example sketch will hang if you don't have I2C disconnected so just keep that in mind, but if you're not using it you can simply comment the temp sensor lines out. For more info on the pinouts you can check out the full tutorial on my Github page:


    Tip 7 months ago

    Great walkthrough! One thing I noticed is that I needed to disable line endings in the Arduino Serial Monitor for the AT_Test_Command sketch (as the string comparisons were failing) but had to have them enabled for the LTE_Demo sketch. Smooth sailing other than that! Nice job.