DMR / Nextion to Jumbo Spot Notes N3ENM
revised 7-23-2018 - 8-03-2018

 

To install the Nextion display on the Jumbo Spot you need to do several things.  Only a bit of soldering is needed and the configuration of the Nextion display is done with free tools.

The information below was gathered from a number of sources and personal experimentation - these links may be of value to you

http://wiki.pistar.uk/Nextion_Screen_install_on_Pi-Star

https://github.com/g4klx/MMDVMHost/tree/master/Nextion_ON7LDS

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjvgZW9j7jbAhUpwlkKHf27CfgQFggpMAA&url=https%3A%2F%2Fwww.hamdigitaal.nl%2Fdownload%2Falgemene-informatie%2FNEXTION_Tutorial_v2.03.pdf&usg=AOvVaw2qbKTziukQxmi6elqAj9G9

 

First, add a 4 pin header to the pins shown here on the Jumbo Spot hat that sits atop the Pi Zero

 

The Nextion comes with a 4 pin cable.  It is attached as shown here - the red wire goes to 5v then blue, yellow,& black to ground.

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Once the display is connected it has to be programmed by adding a file to its memory. There are two ways to get the file into the display.

One involves using the Nextion editor.  This is the method that should be used if you plan on editing the file.  If you just want to get the job done using a microSD card to program the display is easier.

Which file do you use?

The files that are available on the github page ( https://github.com/g4klx/MMDVMHost/tree/master/Nextion_ON7LDS ) are shown here.  The file to use depends on two things.  If you are using the Nextion editor to program the display use one of the files that ends with HMI.  If you are using the microSD card method of installing the file use one of the files that ends in TFT.

The specific file depends on the size of your display. 

Here are the labels from two of the displays I have used.

The top one is for a 3.5" display and the one on the bottom from a 2.4" display.  Note the last two digits that indicate the display size.  Choose the file name from GitHub that has the same name.

 

Using the Nextion Editor

The first way to configure the display is to download and run the Nextion Editor - it is available here:

https://nextion.itead.cc/resources/download/nextion-editor/   I used version 0.53

Load one of the files from this link  https://github.com/g4klx/MMDVMHost/tree/master/Nextion_ON7LDS

I used NX4832T035-L3.HMI as I had a 3.5" display - there are other files for 3.2", 2.8" and 2.4" displays.

Once the file is loaded you need to hook the display up to your PC via a Serial to USB converter ( I used this one  but others should work)

To create and install this file follow these steps:

  1. Load the appropriate file (see info above) into the Nextion Editor
  2. Click "File" then "open build folder"
  3. You should see the folder that will store the file appear
  4. Click on the Compile option at the top of the screen (circled in red below)
  5. Your file should appear in the folder you opened in step 2
  6. Copy the file (ends in tft ) onto the MicroSD card
  7. Place the SD card into the slot on the back of the display
  8. Apply power (5 volts to the red wire and ground to the black) and the file should load into the display

Additional information is here  https://nextion.itead.cc/faq-items/using-nextion-microsd/

 

Using a microSD Card
There is a receptacle on the back of the Nextion display that will accept a microSD card. To install the configuration file from a microSD card follows these steps:
  1. Download the appropriate file from GitHub (see notes above)  The file should end in TFT
  2. Transfer the file to a blank microSD card that has been formatted fat32 (see:  https://www.lifewire.com/format-sd-card-using-windows-4128719
  3. Insert the card into the display and apply power (no more than 5 volts DC to the red wire and ground to the black)
  4. The file should install with installation progress being shown on the display
  5. When done remove power and remove the card
  6. Connect to the MMDVM board and you should see the MMDVM logo displayed as it initializes.
Pi-Star Settings
This screen shot shows the settings I used in Pi-Star under Configuration

Enclosures

- laser cut box - these six pieces assemble to make a box for the 3.2" display.  The only thing that is NOT cut is a hole for the USB power connection - that can be done manually or I may redo the box to include such an opening - some photos follow these images

laser cut sandwich - this pair of boards pinch the display between them to protect the display.  This arrangement is used on my bicycle-mobile unit - the Jumbo Spot attaches to the back of the board with two cable ties (those holes were cut manually) - photos after these images