Knowledge Sharing

When I was first handled with the task of building a Bluetooth and NB-IoT gateway, I was a bit overwhelmed by the messy and complex documentation on the manufacturer’s website. So I decide to do a write guide to start off a hello world example as I learn discover that Thingy 91 module is all about.

Start up hardware

Thingy 91 (from Nordic)

Thingy 91 is a prototyping kit which consist of the IC chip nRF9160 (for NB-IoT communication), and nRF52840 (Bluetooth Low Energy BLE 4.0, 5.0 communication). Simple battery powered electronic hardware to get engineer start up with working on nRF9160.

nRF9160-DK (from Nordic)

nRF9160-DK is similar to Thingy91, an development kit for learning nRF9160 IC chip. That why the it is named “-DK”. It consist of the same IC chip nRF9160 and nRF52840.

Check out this video introduction of nRF9160-DK development kit board.
and a quick introduction to nRF Connect SDK.

An additional big chip is found on this kit. This chip is there for the programming of the IC nRF9160 or nRF52840. A switch SW5 near this big chip is used for selecting the chip that you want to program. You can select nRF52 (for nRF52840 chip) or nRF91 (for nRF9160 chip).

Beside able to program the IC chip on its own board, this development kit can also act as a programmer to program nRF52xxx or nRF91xxx chips on other boards. You can use nRF9160 as a programmer device to program the chips (nRF52840 or nRF9160) on the Thingy91 board via the JTAG cable (10pins ribbon cable).

How to get started?

This was one big question on my head. I done many installations until I also don’t know what I was doing. Here I want to start off by learning how to program a “Hello World” firmware into nRF52840 chip first.

I decided not to rush into things and do things step by step from the basis fundamental first.

What do you need?

• Development Kit nRF9160-DK
• USB micro cable
• A computer with a Windows Operating System

Getting start with nRF9160-DK

You can refer to the reference from this webpage.
https://devzone.nordicsemi.com/nordic/cellular-iot-guides/b/getting-started-cellular/posts/getting-started-with-nrf9160-dk

Summary

1. Install the software nRF Connect on your desktop computer.
2. Open up this software nRF Connect.
3. Go to Getting Started Assistant, click <Install>
4. Open and execute the program Getting Started Assistant to guide you with the steps to take.

Summary from Getting Started Assistant

1. Install the toolchain
2. Clone the nRF Connect SDK
3. Download SEGGER Embedded Studio
4. Set up a project in SEGGER Embedded Studio

Install the toolchain

The whole installation experience is a pain. Please ensure there is no space in the name of your folders. It will not be recognized by the software tools.

1. Install toolchain Chocolatey. Chocolatey tool makes software installation on WinOS looks easy. It will be like typically how we do software installation on Linux OS system. Helps you to automate and create software deployment package for Windows. Learn about Chocolatey here.
   The subsequent steps, we will be doing installation and configuring of Chocolatey from WinOS command prompt.
2. Open a command prompt as an Administrator on your WinOS computer. Press on your keyboard Windows+X. Click on the pop-up menu “Command Prompt (Admin)” or “Windows PowerShell (Admin)”. A command prompt should pops up.
3. Paste the following command text into the PowerShell,
   > Set-ExecutionPolicy Bypass -Scope Process -Force; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072; iex ((New-Object System.Net.WebClient).DownloadString(‘https://chocolatey.org/install.ps1’))
   This will download and install Chocalatey onto your computer system.
4. Enter the following command text into the PowerShell to check if Chocolatey is installed.
   > choco
   You should receive the following message when Chocolatey is properly installed.
   Chocolatey v0.10.15
   Please run ‘choco -?’ or ‘choco -?’ for help menu.
5. Enter the following command texts, and click verify button on Getting Started Assistant. The Assistant should highlight green which indicates that the task is done properly. Do the same for the subsequent command.
   > choco feature enable -n allowGlobalConfirmation
6. Enter the following command texts, and click on verify button.
   > choco install -y cmake –installargs ‘ADD_CMAKE_TO_PATH=System’
7. > choco install git
8. > choco install python
9. > choco install ninja
10. > choco install dtc-msys2
11. > choco install gperf
12. Download and install ONLY the recommended version of GNU ARM Embedded toolchain so that able to cross-compile for ARM microcontroller chips. Follow what nRF Connect assistant tells you to download.
    https://developer.arm.com/-/media/Files/downloads/gnu-rm/8-2019q3/RC1.1/gcc-arm-none-eabi-8-2019-q3-update-win32-sha2.exe
    which is version 8-2019-q3-update of the GNU ARM Embedded toolchain.
    Install the software to the root directory c:
    The installed folder is probably c:\8 2019-q9-update
    Change the folder name to c:\gnuarmemb
    
    Ensure that there is a bin folder under c:\gnuarmemb\bin.
    Use the Verify button to confirmed that you have done it correctly.
    
    Please ignore the following test…..
    Open up “Command Prompt” and key in the following command to check if GNU toolchain is installed.
    > arm-none-eabi-gcc –version
    
    Please ignore the following test…..
    Install onto “C:\gnuarmemb” directory. (recommended by nRF Connect)
    example: “C:\gnuarmemb\GNU Tools Arm Embedded\9 2019-q4-major“
    
    Click verify on your Assistant when this is done.
    

Clone the nRF Connect SDK from Nordic Repository.

Nordic has developed SDK specially for their nRF chip products (only for nRF9160 or nRF5340). These source code are in Nordic repository. The following commands are to copy/update that source code onto our own local computer system.

Enter the following command texts in Windows PowerShell, and click on Verify button.

1. Install West (Zephyr’s meta-tool), a swiss-army knife command-line tool .
   Use pip3 to install west.
   > pip3 install west
2. Create your own directory to store nRF Connect SDK, and create a directory (no spaces in the directory name) ncs under it.
   example: e:\nRFConnectSDK\ncs\,
   > cd ‘e:\nRFConnectSDK’
   > mkdir ncs
   > cd ncs
3. Initialise West meta-tool, and update it
   > west init -m https://github.com/NordicPlayground/fw-nrfconnect-nrf
   > west update
4. Visit the webpage nRF Connect SDK Release Notes to look for the version that you want to clone onto your computer system. Look for the Release Tag to use. In this example, I am looking at “nRF Connect SDK v1.2.0 Release Notes”. The Release Tag that I see from this release is “v1.2.0“. Use this tag for git checkout as shown below. This will fetch the release version v1.2.0 from the repository.
   > cd ‘e:\nRF Connect SDK\ncs\nrf’
   > git checkout v1.2.0
   > west update
   If you want the latest version (may not be a stable version from Nordic), use the command “git fetch origin” instead of “git checkout v1.2.0”. The command “west update” simply update the files to that version.
5. Install a list of required Python modules.
   > cd ‘f:\nRF Connect SDK\ncs’
   > pip3 install -r zephyr\scripts\requirements.txt
   > pip3 install -r nrf\scripts\requirements.txt
   > pip3 install -r bootloader\mcuboot\scripts\requirements.txt

Download SEGGER Embedded Studio

Download and install SEGGER Embedded Studio.

Set up a project in SEGGER Embedded Studio

Execute the SEGGER Embedded Studio software.

1. Use command prompt to navigate to the folder where SEGGER Embedded Studio is located. In this example, it is located at “e:\nRF Connect SDK\arm_segger_embedded_studio_v442a_win_x64_nordic\bin\”
2. Execute the file emStudio.exe to launch the software.
3. A pop up screen may appeared indicating “No commercial-use license detected”. Activate your free license.

Setup the path of the Zephyr Base (the location of your cloned Zephyr repository, path ncs/zephyr), and the path where GNU ARM Embedded Toolchain is installed.

In the software go to Tools > Options, and select the nRF Connect tab.

In our example, the path for

• Zephyr Base, “e:\nRFConnectSDK\ncs\zephyr“
• GNU ARM Embedded Toolchain, “c:\gnuarmemb“

You can now start opening your nRF Connect project. Select File > Open nRF Connect SDK Project.

Follow the setting of the screenshot on the right.

For the board name, remember to select the name ending with xxxxxxns. Which means Non-Secure version.

• CMakeLists.txt (location of the project makelist. Typically located at ../ncs/nrf/samples/nrf9160/lte_ble_gateway/CMakeLists.txt)
• Board Directory (location of the board used for the project. Typically located at ../ncs/zephyr/boards/arm/nrf9160_pca10090 )
• Board Name (names for the board will be automatically generated when the board directory is selected). Always choose the board name with xxxxns at the end of the name. ns means Non-Secure.
• Build Directory (the folder of where the output build will be located, will be automatically generated when the CMakeLists.txt is selected. The build… will be generated in the same directory of the CMakeLists.txt)
• Check the box “Clean Build Directory” so that the outdated build is not cache.

Success!!!

Successfully loaded

Problems encountered

• Issue installing Chocolatey due to outdated software. TLS 1.2 at a minimum version.
  Error message “DownloadString” with “1” argument(s): “The request was aborted: Could not create SSL/TLS secure channel.”
  reference: https://chocolaty.org/docs/troubleshooting
• When verifying “choco install -y cmake –installargs ‘ADD_CMAKE_TO_PATH=System'”, an error message occurred.
  Error message is ” ‘cmake’ is not recognized as an internal or external command, operable program or batch file.”
  Solution 1: is to download and install cmake software. https://cmake.org/install/
  It is found that cmake is already installed, just that it needs some repair only. You may need to install and uninstall.
  Remember also that you may need to go to Tools > Options > nRF Connect > Executables > CMake Executable, to set the location of the newly installed cmake program.
  Solution 2: set environment path in the command prompt.
  $env:path += “;C:\Program Files\cmake\bin”
  After this, key in cmake in the command prompt. It should work.
• SEGGER software keep asking me to activate license.
  Solution: Close Segger Embedded Studio and open any SES project from Nordic SDK.
  https://devzone.nordicsemi.com/f/nordic-q-a/43274/my-segger-license-is-never-activated
  Example of such a SDK project file is “nRF5_SDK_15.2.0_9412b96”
  Open a *.emProject files using the SEGGER program.
  The file can be found under the folders “examples\peripheral\blinky\pca10056\blank\ses”
  There will no longer be a license problem the next time you open the SEGGER.
• What I learned is Zephyr is a OS is based on a small-footprint kernel designed for use on resource-constrainted systems.
• Don’t give name to a directory that have space inside.
• Error message while opening a nRF Connect SDK project.
  “warning: BSD_LIBRARY (defined at…….. has direct dependencies TRUSTED_EXECUTION_NONSECURE with value n, but is currently being y-selected by the following symbols: -MODEM_INFO (defined at…….”
  Solution: When choosing the board name, choose one with name ending with xxxxxxns. Reason: bsdlib can only be used from a non-secure application and you need bsdlib to use the modem.
  Reference: https://devzone.nordicsemi.com/f/nordic-q-a/57722/cmake-error–open-nrf-connect-sdk-project

Other good tutorial resources

• nRF Connect SDK Tutorial – Part 1
  https://devzone.nordicsemi.com/nordic/cellular-iot-guides/b/getting-started-cellular/posts/ncs-tutorial—temporary#h769sk6kqovea15p99jn16lstat1dtpuuw
• nRF Connect SDK video introduction
  https://youtu.be/sHJTIiE2PA4

Updating the Modem firmware on nRF9160

Remember to put the switch to nRF9160 (instead of nRF52840) before the programming. You can switch and click on the “Read” button from the nRF Programmer software to check which chip the nRF9160-DK board is connected to.

The following tutorial is a good reference to show us how to update the modem firmware to the nRF9160 chip on the nRF9160-DK board.

• https://devzone.nordicsemi.com/nordic/cellular-iot-guides/b/getting-started-cellular/posts/getting-started-with-nrf9160-dk

Update Thingy91 with the latest firmware

You can download the latest “precompiled application and modem firmware” from this URL
https://www.nordicsemi.com/Software-and-tools/Prototyping-platforms/Nordic-Thingy-91/Download

Inside this package, you will see 4 folder,

• images_dfu_bin (programming nRF52840 nRF9160 chip via bin format using ???)
• images_dfu_hex (programming nRF52840 nRF9160 chip via hex format using bootloader method)
• images_full (full firmware image, programming nRF52840 nRF9160 chip firmware via J-Link debug probe/development kit)
• mfwnrf9160110.zip (modem firmware)

Let’s use the full firmware image method. Inside the folder images_full, you will see,

• thingy91_at_client_2019-11-29_d3130d77.hex (flash nRF9160 with only AT Client application)
• thingy91_ltem_2019-11-29_d3130d77.hex (flash nRF9160 with Asset Tracking Demo (connect to nRF Cloud Server for Demo purpose) using LTE-M network)
• thingy91_nbiot_2019-11-29_d3130d77.hex (flash nRF9160 with Asset Tracking Demo (connect to nRF Cloud Server for Demo purpose) using NB-Iot network)
• thingy91_nbiot_legacy_pco_2019-11-29_d3130d77.hex (???)
• thingy91_nrf52_usb_uart_bridge_2019-11-29_d3130d77.hex (flash nRF52840 to act as a USB-UART converter chip)

There are 3 firmware that needs to be updated.

• thingy91_at_client_2019-11-29_d3130d77.hex
• thingy91_nrf52_usb_uart_bridge_2019-11-29_d3130d77.hex
• mfwnrf9160110.zip (modem firmware)

They can be loaded via the nRF Cloud Programmer software.

For modem firmware, after going into the programmer software, go to the lower right side of the screen and load in the *.zip file (modem firmware). Remember to slide the switch on the Thingy91 to select for the nRF9160 chip.

For the thingy91_at_client firmware, in the programmer software load up the hex file. Then click “erase & write” to begin flashing. Remember to slide the switch on the Thingy91 to select for the nRF9160 chip.

For the thingy91_nrf52_usb_uart_bridge firmware, in the programmer software load up the hex file. Then click “erase & write” to begin flashing. Remember to slide the switch on the Thingy91 to select for the nRF52840 chip.

Playing with the nRF9160 modem

Everytime the board is plugged in, there will be 3 COM port that appears. 2x COM belongs to the nRF9160 chip, one maybe for the AT command, and the other maybe the logging messages from the modem module. 1x COM belongs to the nRF52840 chip.

Using the software LTE Link Monitor to initialise the modem and send AT command.

First connect the device, communication port by selecting the connected Thingy91 or nRF9160 device.

Some console text will starts to appear. If not, can also press the reset button on the hardware board. Key in the command “AT” to check if the board is responding to this AT command.

Key in “AT+CGMR” to check the modem firmware version.

Key on the modem command “AT+CGMR” to initalise and start the module. The indicator on the software Modem, UICC, LTE, PDN will all start to turn green.

Network will display, Singapore Telecom

For more information on AT commands for NB-IoT, refer to this page.

Flashing with AT firmware only

AT+CEREG=4
AT+CFUN=1 (connect to LTE network)

<- Back to Bluetooth Resources Page

This page contain references to buying of a coin dispensing machine and notes-to-coin machine. Coins, Notes and token solution for your automated business payment collection.

Bills and Coins Machine Product Companies

• http://www.ictgroup.com.tw/index.php

Bills to Coins Changer

• https://www.coinchanger.sg/ (Singapore)
• http://www.cointech-group.com/en/index.asp (Singapore)
• https://www.bmigaming.com/games-vending-changers.htm
• https://www.kleen-ritecorp.com/c-203-changers-counters.aspx
• https://www.candymachines.com/Bill-to-Coin-Change-Machines-C407.aspx
• https://www.sprintquip.com.au/change-machines
• https://www.gumball.com/collections/change-machine
• https://www.pwslaundrywest.com/i-16069501-standard-mc400rl-bill-to-coin-changer-rear-load-for-change-or-tokens.html
• https://www.ebay.com/bhp/change-machine
• https://www.amazon.com/Best-Sellers-Office-Products-Coin-Changers/zgbs/office-products/490844011
• https://www.alibaba.com/showroom/coin-change-machine.html

Bills Validater / Note Acceptor

• https://www.8linesupply.com/shop/parts-supplies/pyramid-technologies-apex-stacker-singapore-bill-acceptor/ (Singapore)
• https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20181013190155&SearchText=bill+acceptor
• https://innovative-technology.com/products/products-main/128-bv20

Coin Accepter

• https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20181013190234&SearchText=coin+acceptor

Coin Dispenser (Hopper)

• https://www.asahiseiko.com/english/product/productcat/hopper/
• http://www.ictgroup.com.tw/pro_a.php?category=66
• https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20181013191714&SearchText=coin+hopper

Custom Cash (notes & coin) system.

We can help you to design a system suitable for your application use.

For customised automatic cash (notes and coins) payment collection system, please contact our sale engineer with your project details for a quotation.

Cashless Payment Terminal

The principle of crimping a 2.54mm pitch female socket header and a 1mm pitch connector is fairly similar.

The difference is that a 1 mm pitch connector pin is much tedious to crimp because it is too small. For most people, a magnifying glass is required while doing the crimping.

    1mm pitch pin for crimping onto wire

receptacle socket for housing the pins

Not only it is small in size, the tool for crimping this 1mm pin is also difficult to find. This tool is rare, hence it is also very expensive. The crimping tool for a 1mm pitch pin (0.039″) can cost a couple of hundreds to a thousand of dollars. The tool name from JST (JAPAN SOLDERLESS TERMINALS) is called WC-SH2832 (Crimp Tool, Ratchet).

JST Connector pitch: 1mm

Connector pin width is less than 1mm

Wire Gauge Size is 32 to 28 AWG

Crimping 1mm pitch pin Step by Step

1- sleeve gripper for gripping the wire sleeve as a strain relieve,
2- wire strand gripper for the contact to the wire strand.

1. Close up the sleeve gripper for the wire’s sleeve. This allows the pin to easily grip the wire when you position the wire for crimping.

   

2. Insert the wire into the pin. Position it nicely with the pin’s sleeve gripper end holding the wire sleeve. Ensure that the wire sleeve is over the sleeve gripper but before the wire strand gripper.
       
3. Crimp the sleeve gripper first. Then proceed to crimp the exposed wire with the wire strand gripper.
4. After crimping, ensure that the width of the pin is less than 0.88mm. If the width is too big, it will not be able to fit into the connector housing. Use your crimper to lightly squeeze it narrower.
   
5. After the wire is crimped to the pin, pull the wire to ensure that the crimp is tight. The crimp pin should not give way.
   
6. You should be able to easily slide the crimped wire into the connector housing without much force. If it is difficult to insert in, it is probably not done correctly. Redo again and do not force the pin into the receptacle housing.

Contact PIC-CONTROL for 1mm pitch wire assembly

For custom wire assembly of any 1mm pitch connector pin, please contact PIC-CONTROL.

This page is to demonstrate how easy it is to solder very small electronic SMD (surface mount device) components on your PCB board. It is easier to work with compared to through-hole components. The component insertion time is shorter, and there are no component’s leads to cut away after the soldering. This save time and cost.

SMT (surface mount technology) methods of assembly PCB has significantly improve the production efficiency. Not only it reduces the board size and board cost, SMD components are usually costing lesser. The SMT design also make automation of PCB assembly much more efficient.

The re-work with SMT boards is also simpler. Using a hot air blower, it is very simple to de-solder and re-solder of a 44 to 100 pins IC chip.

There are many methods to working with SMT components. The following presents some of the cost effective methods suitable for low volume production.

Advantages of Working with SMT Board

• Smaller
• Faster
• Cheaper
• Lower probability of being obsolete

The board size can be smaller reducing your product size and weight. The use of lesser material can help minimise cost.

As more production is using SMT, the cost of the surface mount components will usually be cheaper than the through-hole version. The chances of the component’s package being forced end-of-life or obsolete is also lower compared to through-hole.

Due to the simple assembly of surface mount, it simplifies the assembly automation for mass production. This not only speed up the assembly process, ultimately the cost of assembly is going to be lower.

The small component and devices will also use up less space for your logistic storage. It takes less space to keep your component parts and your finished product. The reduce weight and size also helps to lower your shipment cost.

Disadvantage of Working with Small Components

• Not suitable to deploy in a very dirty and dusty environment without an enclosure.
• May be too small to work with for some technician.
• Additional tools and equipment may be required

SMT is not suitable to deploy in a very dusty and dirty environment with proper enclosure protection. There is a conductivity in every material. A dust may fall in between the fine pitch of the IC chip and unintentionally causes a connection or short circuit. This may result in a faulty circuit operation. It is important to keep the circuit free from dust and dirt especially when the pitch distance between the pins are 1mm and smaller.

Some technical may find it harder to work with SMT components. A better eye sight compared to working with through-hole compoents. Their hand should not be shakey when placing very fine pitch components.

While SMT soldering can be done by an ordinary soldering iron, some tools are recommended to better help you work with SMT.

• A pair of good staineless steel tweeter.
• Flux to clean the contact surface.
• Hot Air Rework Station for doing rework.
• Reflow Oven for small volume mass production.

The following are some useful videos that was posted in You-Tube. Check them out to see for yourself how easy is it to work with SMT components and boards.

Manual Iron Soldering of a Passive Component

SMT components may be small but you can still solder with a soldering iron with ease. This is a video of how a SMD resistor (size 1206) is manual soldered using a solder iron. You can easy solder resistor, capacitor, inductor and diode using this method.

Smaller component size like 0805 is still relatively easy to work with using a simple tweeter and a iron. Size 0603 component can still be managable. Component size 0402 and below will be much tougher. It may be too small for your tweeter to hold. It is still possible but much challenging to work with.

The size which is comfortable for a technician to work with is subjective. As a general rule, the minimum size of 0805 should be easy enough to work with for most age group. For technical that is age 40 and above, they may find it challenging to work with component size 0603, 0402 and below.

Manual Iron Soldering of Fine Pitch IC Chip

This method of soldering small SMT IC chip is applicable to IC pin pitch as low as 0.6mm distance apart.

The key ingredient is the use of flux to keep the solder flowing like a liquid so that it will not bridge as a lump. Flux may not be neccessary for passion components or IC chip with pitches of 1.27mm and above. It is a must for SMT IC components with fine pitches.

A clean iron tip will improve the soldering experience. Always tin your soldering iron tip when it is not in use. Tinning acts as a layer to prevent the soldering tip from oxidising. An oxidised tip will act as an insulator prevent the heat from flowing to the component’s lead. Tin the tip when you are not using the iron for the next 5-10 minutes. Tinning is recommended if the iron heating is left idling for some time or before it is powered off.

De-soldering and Re-soldering of Fine Pitch IC Chip

SMT IC chips may seems small to work with. Actually the rework is much simpler when you have a Rework Station equipment. This equipment blows out hot air which will melt the solder on the board. This allows you to remove the SMT component easily with a tweeter. The same equipment can also help you to solder SMD component with ease.

Reflow Soldering Method for SMT PCB Assembly Production

Reflow method is a simple method which allows you to solder your boards at one go using a reflow oven. The following steps provides you an overview of the PCB assembly process.

1. Apply soldering paste to the bare PCB board using a stencil.
2. Place your SMT components on the PCB board that was applied with the paste.
3. Place the assembled PCB board into the soldering oven for a couple of mintues.
4. Yes. Your boards are now soldered. It is so simple.

The following a a short video which demonstrate to you how the process is like.

Self Alignment of SMT Components During Reflow Soldering

For those who had not experience in SMT soldering before, it can be intemiding. One common question is the concern of not placing the component perfectly on the board. While smaller component can be more changllenging to place, the good news is that you do not have to place the component with precision. As long as the component’s lead is touching the SMD pad on the PCB board, that would be good enough. The component will be pull to alighnment automatically during the reflow oven soldering process.

The following video demonstrate the self-alignment of the small SMD components during the reflow oven soldering process.

That’s All for SMT Soldering and Assembly

Simple isn’t it. Once you done it for a few times, I am sure you would not want to go back to through-hole components again.

This is not to say that through-hole components are no good. For connectors where there are a lot of physical handling with user plugging in and out, it is recommended to go for through-hole connector. The mounting will be stronger and is less likely to be damaged due to rough handling. Electrolytic capacitor is currently less expensive than the SMT version.

There are pros and cons working with SMT. I would say SMT has much more benefits compare to through-hole. It is definately a direction which you should move towards.