Node-RED for Unipi Neuron
This manual will guide you through the entire process of installing Node-RED into your Neuron unit. Before the installation please make sure your unit was delivered undamaged and without any visible defects.
Neuron
SD card preparation
We strongly recommend using industrial SD cards. If you use a laptop, bear in mind most laptops do not feature a microSD card slot and will require a suitable SD or USB adapter. A suitable card can be purchased on the Unipi e-shop.
For a smooth running of Node-RED on Unipi Neuron or Unipi 1.1 units, you will need a card with a capacity of at least 4 GB.
Flashing OS form Windows PC
Download and install the program BalenaEtcher.
Launch the installed BalenaEtcher and choose Select Image from its main menu. Here select the downloaded disk image, it can also be in the archive, as you downloaded it from our website.
After successfully selecting the OS to flash, you have the option to Select target to the right of the OS image selection to choose the appropriate disk drive. Select the drive with the prepared SD card here.
Then just confirm by clicking on Flash!
Maximum caution is essential when selecting a disc drive. Selecting the wrong disk drive would result in data loss on media other than the desired one (SD card).
After flashing, your operating system may detect the SD card in your PC as a new disk drive, which it will not be able to recognize and may ask you to format it. Click Cancel to close this dialog window.
Windows may also notify you that the drive is unaccessible. Also ignore this message.
If you have successfully flashed the image to the SD card, the card will be identified as boot after re-insertion into the PC.
If you have flashed Mervis OS to the SD card, it is possible to perform the last step: enable SSH. The easiest way to do this is to create a file named ssh.txt, or just ssh without the suffix, in the main boot directory of the card. For non-Mervis OS, the SSH connection is enabled by default and does not need to be enabled this way.
If you enable SSH, you have to secure the operating system or disable SSH access again, otherwise unauthorized access may occur!
At this moment, the OS is safely flashed onto your SD card (with SSH enabled). Unplug the card from your PC, remove it from the adapter (if you used one) and insert the card into your Unipi unit.
Insert the card ONLY when the unit's power supply is unplugged!
Insert the card into the slot with the back facing up (i.e., the gold connectors facing you). Then plug in unit power supply.
Starting the unit with the newly flashed OS on the SD card will take a little longer - about 3 minutes. This is due to the necessary OS configuration.
Detecting the unit's IP address
To detect the unit's IP address you can use any of the available LAN network scanning tools. You can also gain the IP address from the DHCP server (if you have access to it). For this tutorial, we selected the Advanced IP Scanner program.
Download and install it, or just launch it. The Advanced IP Scanner interface looks like the following:
For automatic network selection, click on the 
icon to start detection of all available networks on all available adapters of the PC. The specific range can be adjusted manually.
For network scan click on the 
button.
Scanning local networks will take a couple of minutes. Please wait until your device is displayed.
Remember the IP address - you will need it later when working with the unit.
Pre-installed SW
The OS image you just uploaded into your unit also contains the preinstalled EVOK open-source software - an Unipi-developed application programming interface (API) for direct communication with Unipi hardware.
Also available is a practical demonstration of using the API in the form of a simple web application (Unipi Control Panel) serving as a user interface for all inputs and outputs on the unit. To access this interface, open your web browser and enter the IP address of your unit with the port number :80. Port number is optional, as it is the default webserver port.
For example:
192.168.1.10
or
192.168.1.10:80
The application's interface looks like this:
Another software included in the disk image, which is now also uploaded in your unit, is Node-RED. It is an open-source programming tool for connecting hardware devices, various APIs or online services. In this case, the Node-RED software already contains the EVOK API. This API is represented by a pair of nodes in the left panel, section Unipi - unipi input and unipi output made to control both analog and digital inputs and outputs.
Connecting to the Node-RED interface
To access the Node-RED programming interface, open a web browser and enter the unit's IP address into the address tab. Don't forget to add the :1880 port number.
For example:
192.168.1.10:1880
The following interface will appear:
You have probably noticed the interface already contains a project. It is a demonstration project for reading inputs and writing to outputs, which is connected with a web user interface → so-called Dashboard. This project (flow) is available for download at the end of the article.
To access the interface, add /ui suffix behind the address with the port number.
For example:
192.168.1.10:1880/ui
The following interface will appear:
You now have everything you need to create your projects.
Node-RED security
If you did not set up login using the following guide, you expose yourself to a risk of unauthorized access to the Unipi unit. That may lead to potentially dangerous changes resulting in downtimes or limitations. At the worst, unauthorized tampering can damage connected technologies or endanger personnel at installation sites.
That said, it is very important to have your system secured every time you create a new project.
As you will communicate with the unit using the SSH protocol, you need to know the unit's IP address and to have an SSH client installed on your unit. Among the most frequently used programs is the PuTTy application - if you don't have it already, follow this guide.
For transfer files between your PC and the Unipi unit you can use the WinSCP utility. Login is the same as for SSH.
After that, just follow this guide on the official Node-RED webpage.
Downloadable projects
Node-RED projects are called flows. On the link below you can download a file with a flow for Unipi Patron / Neuron / Axon units.
