Wireless Nextion Display You Say?

When I started tinkering with the JumboSpot and small OLED displays, it got me interested in larger and informative display options, so I quickly picked up a few Nextion style displays as covered a few months ago in the "Bigger Display for Jumbo/China/Covert" article.

Even though having a larger and more informative display to be used with the MMDVM based hot spot is great to show callsigns, name, location, IP addresse, temperature, etc, that means the hotspot can not be put where I want the hotspot for maximum RF range and still see the display.

Be sure to purchase a Nextion display and not a TJC branded one. Only the Nextion version has English development software. TJC screens are designed for the China market or those that can read Chinese software. Otherwise, they are the same thing and would work fine with any MMDVM Pi-Star Hot Spot

So, what about making the display itself remote from the actual hot spot?  Seemed like a good idea and here is what I have done to make this a reality.

Wireless Nextion Display

Getting the correct signal from the hot spot was easier than I thought after some research and decided instead of trying to send the signal over wireless serial blue-tooth connection to a remote receiver that feeds a Nextion display that using 70cm amateur radio spectrum would be just be a bit more fun to experiment with.

Silicon Labs is just one of the companies with components
that make this small data transceiver module a reality

Inexpensive HC-12 modules allow serial based communication over a wide range of speeds and can be configured to operate on a number of predefined channels set by the manufacturer or configured by the end user. Here is a great user manual I found on the Elecrow website that will fill in some of the blanks on its capabilities.

The HC-12 can be driven from from the TXD, GND and VCC pins on the duplex or semi duplex hot spot boards easily.  All I needed to add was a 1N4007 diode to drop the voltage a little in order to not over drive the HC-12 module since its sensitive to over voltage.

Since I was not interested in providing a two way wireless connection, there was no need for the RXD connection between the hotspot and HC-12.

Steve K2GOG SDR capture of MMDVM DMR audio and HC-12 pulses

After getting everything connected, crossing my fingers and apply power, I started to see pulsed signals being sent on the default HC-12 module frequency of (3) 433.400 MHz as shown on the screen capture by using an inexpensive SDR dongle sch as the NooElec Nano3 and the popular SDR# software package.

The other two signals shown is the output or transmit signal generated by my duplex hotspot that was connected to the HC-12 and was set to operate on (1) 432.525 MHz, only 875 kHz away.

The very narrow continuous unmodulated signal at (2) 433.063 MHz seems to be coming either from my cable modem or cable line, but does not seem to be an issue I can easily fix, so just ignore that.

Within the Pi-Star dashboard, I selected screen type as "Nextion", port as "Modem" and Nextion Layout as "ON7LDS L3" since that is what I use with my 4.3 Inch Nextion display that runs a modified version of one of the nice layouts found in the file section of the Nextion Ham Radio Screens Facebook Group

Connecting the HC-12 module to the Nextion display was a little more tricky to receive signals though.  I connected the RXD and GND from another HC-12 to the Nextion display and ran +5V to power up the display.

I needed an isolated power supply with another 1N4007 diode to power up the HC-12.   Everything worked on the second try!   The first try was when I accidentally forgot to use a diode to drop the voltage and "smoked" an HC-12, but that is why I ordered a few spare just in case!

On the second try I thought I had a different issue, but as it turns out the default setting of the HC-12 is pretty high transmit power and I recall the manual saying to separate modules by a few feet.

Once I moved the contraption across the room, my display was updating with users chatting away on TG 91 worldwide DMR talk group!

An Additional Future Experiment

Here is where I hope to get some people interested and assist with an extra added feature/benefit.  What about decoding the data packets that the HC-12 transmits by using the SDR?

Its possible to decode weather stations, door bells and other 433 MHz range devices with the rtl_433 application when used with an SDR dongle, so maybe someone can find a way to translate the pulses and view those on a computer or smartphone connected to an SDR?

There are likely many protocols that an HC-12 can send and receive, so why not figure out a way to add another to read what the Nextion display expects to see and render that in some sort of application.

It is easy to record and playback "spectrum" with SDR#. To play back the file related to this article, instead of  selecting your own SDR device in the menu drop down, select "IQ File (*.wav) and navigate to where the base-band recording downloaded here was saved to. Then press "Play" and be amazed! 

To get anyone (and everyone) started, I did a base-band recording that can be easily played back in SDR#. You can play back the file as if you were in real time listening to the signals sent by the Nextion. Its even possible to use DSD+ to decode the active DMR audio signal too! 

Caution:  Using DSD+ can be daunting, so look elsewhere on getting that to work.

This way you can know who is speaking to match it against the pulses sent by the HC-12. The pulses will show call sign, talk group and DMR ID to whom ever can decode it so you know what sort of information to look for in the packets.

Just 37 seconds of 2 MHz wide of spectrum took up 225MB, so I have it hosted on Google Drive.

Download UHF Baseband File Here

The First HVDN Contest

If you can make some progress, share your tips in the comments below or send a private email instead via one of the HVDN contact forms.   

First maker, hacker, ham, etc to make MAJOR documented progress, Hudson Valley Digital Network will reward your efforts with an HC-12 and an RTL-SDR device, so ready.....set..... 01000111 01001111 00100001

MMDVM JumboSPOT board: Mods you may need

This is the JumboSPOT board that was/is sold on ebay and other online places. This board along with a Rasberry Pi Zero and a SD card loaded with PiStar makes up a Digital Radio Hotspot.

Depending on when you purchased your board and for what price, you may need certain modifications. The following mods have ONLY be tested / verified on the above board. As with anything in life, you take on the risk and responsibilities of preforming these mods. If you don't know what you are doing, STOP and don't do it!

Antenna mod

If you installed the SMA connector at P3 and plan to use the included SMA external Antenna you need to remove the cap ( see A in above picture ). This removes the connection to the internal ceramic Antenna ( not shown about ) at AE1. Bottom line is that you should not run two Antenna's so removing C28 makes sure that only Antenna is P3.

Flash FW mod

Most early boards shipped with only the 10 pin connector soldered as in the above picture. This meant that you were unable to flash updates to the STM32A103 microcontroller chip. Thus the two pins in the above picture ( marked B and in the red rectangle ) need to be connected to the Rasberry Pi's GPIO pins 20 and 21 which will be right below them.

It is a direct pass through, NOT a jumper as most people assume. So you just need to add a female header to your JumboSPOT board and a male header to the Raspberry Pi. Current boards place a 10 pin female header on both sides of the JumboSpot, which will work, but only thoes two pins are needed. Once the pins are connected you will be able to use the PiStar Firmware update script to update your JumboSpot to the latest version of HS_HAT which is displayed on the PiStar admin page.

OLED display mod

If you just purchased the JumboSPOT board it most likely did not come with an OLED display. You can add one later on if you like. Just look for " 0.96" I2C IIC SPI Serial 128X64 White OLED LCD LED Display Module for ArduinoG9K " or similar. The display gets connect to the top row in the above picture ( refrence "C" ) and not the bottom row that is marked. The main issue is that the pins must match the board pins which are listed above. From left to right they are [3.3v] [GND] [SCL] [SDA] So since you solder the display so that it's facing out the screen you purchase should match that config like so:

 I was able to find this module for 450% less then the ones listed as compatible to the JumbSPOT so don't get fooled by the seller, you can use compatible modules as long as it has the correct pins and supports "I2C IIC SPI Serial". Also note that the display will NOT turn on unless you have it configured and PiStar attaches to a server on the Internet ( as in Brandmister etc ). In PiStar http://pi-star.local/admin/configure.php make sure you have it configured as in:

Adding Ethernet to your Pi Zero mod

This one requires no-soldering! Just chose the correct part from eBay or your favorite Chinese vendor. The PiStar distribution will support an Ethernet adapter out of the box. It's even smart enough to use Ethernet over WiFi and fall back to WiFi if Ethernet fails. But which one to get. If you search for "MMDVM Hotspot Ethernet Adapter" you will be paying the most you can pay. If you look for "Micro USB 2.0 to Ethernet 10/100 RJ45 Network LAN Adapter" you will find ones EIGHT TIMES less! Make sure that it supports Linux and you will be safe. Also I suggest getting one more then you need. When I ordered three, only two worked. Since I only needed two it was worth buying extra ( these parts are really REALLY cheap and cheaply made ).

 

What do you think?

Please leave constructive comments. If you have mods of your own please share. Like most of you out there I was attracted to this hobby because I could MOD things, make them better! So pitch in and share your knowledge!

Why Update To Pi-Star Update 3.14.3?

Most of the folks involved with HVDN agree that DMR is the digital voice mode that is spurring on massive growth in the hobby compared to Yaesu Fusion (C4FM) and Icom D-Star (GFSK) digital modes.

This HVDN article talks about Pi-Star
version 3.14.3 and its new cross mode features

Other digital voice modes that amateur radio operators are experimenting with include NXDN and P25.  While Fusion and D-Star were developed just for amateur radio use, DMR, NXDN and P25 all started life as commercial standards.  DMR was the first to see "ham grade" equipment for sale and truly sparked the digital growth we see today.

DMR is an open standard and many new vendors took advantage of this and started to offer radios at budget price points to spur experimentation with radios marketed directly towards the amateur radio community.   Traditional "ham equipment manufacturers" such as Yaesu and Icom pretty much missed the boat by continuing to push closed standards, with Icom having a very high licensing rate of its D-Star technology built by the Japanese Amateur Radio League almost 20 years ago. The only vendor who paid to get on board with Icom's D-Star is Kenwood with its 2016/2017 released $500+ TH-D74 radio.  Limited options and expensive equipment has kept many away from D-Star as a result.  Yaesu has fared a little better, but really not by much until recently with new affordable equipment.

All These Acronyms...

There is a comparison of the different modes mentioned above at the bottom of the "Basics of DMR" page on HVDN for those interested in more details as it gets confusing quickly for some people.

Because of all these different digital modes, different radios can not communicate with each other and take advantage of benefits and featured offered by digital technology compared to analog FM or NFM. Analog FM equipment is what has been the dominant amateur choice of non-HF radio for at least 40 years and digital migration is kicking and screaming its way into the amateur radio community. A universal digital standard is needed to truly replace FM.

Your very own repeater? Sort of...

The SharkRF OpenSpot was the first "hot spot" type device to provide cross digital mode support.  What this meant was a DMR based radio could talk on the D-Star network to other users with D-Star radios.  It also provided the ability for a Fusion radio user to talk on parts of the DMR network.

SharkRF Openspot was the first cross mode capable hot spot
device to see mass adoption by amateur radio operators

With DMR radios such as the TYT MD-380 or Radioddity GD-77 costing less than $100, it gave many amateurs a taste of what 80,000+ individual users already registered to use and also be able to talk to those with just Yaesu Fusion or Icom D-Star Equipment to see if they are missing anything.

Converting analog FM repeaters is not always the best option for those looking to add digital repeater capabilities to a specific area, so "hot spots" have found a unique niche to fill the gaps while owners of great sites for repeaters decide what to do when thinking about what digital modes to support for wide area coverage to eventually replace much of the FM based repeater infrastructure.

One of the latest "hot spot" devices provided by a community of developers. This MMDVM board
provides simultaneous transmit and receive or "full duplex" operation. It is like a "mini repeater" 

Pi-Star & 3.14.3

Another "hot spot" type of device based on open source design is sometimes known as the ZUMspot, JumboSPOT, ChinaSPOT and a number of others.  The team behind Pi-Star took somewhat more "scary" command line interfaces and made things easier by way of nice visual interfaces. These all mostly run a user interface called Pi-Star and the latest revision does something very interesting.

Version 3.14.3 allows anyone with a Yaesu Fusion radio to also communicate over DMR, NXDN and P25 now. This is pretty monumental where now that Yaesu has some lower priced new Fusion radios such as the dual band hand held FT-70DR or higher powered mobile FTM-7250DR, users an now use the inexpensive Pi-Star driven hot spots to connect with users of NXDN and P25 plus of course those on DMR. It also lets someone who may have purchased surplus commercial NXDN or P25 radios communicate over DMR or Fusion.

Turn in 1000 Feet: Excitement Ahead

Could these largely community and developer driven efforts be just what some of the more well known amateur vendors need to take advantage of?  Notably absent is any form of Icom D-Star anything in this latest revision.  Kenwood sells commercial NXDN equipment as well as P25.  Icom also sells commercial P25 equipment.  Yaesu's sister brand, Vertex, also has P25 equipment on the market.

One great example of a community member working with a commercial vendor is Ty,  KG5RKI who has alternate firmware available to increase features in certain radios.  Retevis partnered with him to officially support his work.  Will we see Icom, Yaesu, Kenwood or even Alinco take a similar approach?

Could DMR just be the entrance ramp towards a NXDN or P25 amateur future?

All these digital modes also do much more than just transmit voice. They can also be used to share GPS location and text messages in the same narrow frequency bandwidth used, some at the same time as voice communication.

From just May of 2017 to today,  by May of 2019 it should be interesting what else continues to see development and what commercially made equipment comes to market.

Updating to the latest 3.14.3 release is as easy as logging into your pi-star interface, going to "expert" mode and then to the SSH function.  After providing username "pi-star" and your password or default "raspberry",  type in "sudo pistar-update" and then after that completes, run "sudo pistar-upgrade"

Please note that you may need to modify certain hot spot boards to allow firmware upgrades, but you should find no shortage of those with knowledge to help you along the way.

Sample Resources

• Live Discussion: Have a look at the HVDN Net & Activity page 

• Social Media:  Facebook has a number of users groups such as JumboSpot, MMDVM & Digital 

• Local Discussion:  Local Hudson Valley DMR repeater directory (always under construction)

• In Person:  HVDN will start having in person meetings in Rhinebeck, NY later this summer once the location completes construction.

Join HVDN for FREE for the first year. Details here.

Bigger Display For Jumbo/China/Covert/

The small OLED display that comes as part of the ZUMspot and its spawned derivatives is not a good size for use in the car, so here is how to add a larger display to your hotspot.

Just the beginning of using a Nextion Display

The small OLED display...

First, a few helpful tips....

Be careful what you buy! Nextion and TJC displays look the same, but are not the same! Some are marketed as Nextion compatible. Just be sure you know what you purchase. Nextion is an international version and TJC are China only. 

If you speak/read English, you may want to customize the screen layout, be sure to purchase a Nextion original and not the TJC one, unless you want to learn to use the same editing software but in Chinese.  

Think carefully about what size display you want. The available sizes for TJC and Nextion displays  have some different options, probably to help avoid confusion for buyers. Same with part numbers.

Nextion Display Size Options

 Nextion Display Editing Software - https://nextion.itead.cc/resources/download/nextion-editor/ 

TJC Display Size Options

   TJC Display Editing Software - http://tftdata.tjc1688.com/USART%20HMI/USART%20HMI.rar

Wiring Up the Display

The Nextion and TJC displays often come with the mating connector for the display and pin connectors that fit on standard headers in use on Raspberry Pi and other devices. Here is where you connect those wires to the Nextion named set of four pads.

Creating An Image Overlay

The Nextion and TJC displays offer two different way to get a file like the below loaded into the display. All that is being sent from your JumboSpot type device via the TXD and RXD wires is data that relates to where it should show up on the display. 

Easier:  Use the micro SD card on the back of the display to load an image to the screen.

Harder:  Connect and upload the *.tft or *.hmi files via a SSH connection. Not providing instruction for that here.

Screen Sample

Here is what a sample screen would look like for use with the JumboSpot or similiar type of hotspots. However, this same sort of display can be added to any other hotspot or repeater controllers that are based on the Raspberry Pi.

There are existing screen files on a Facebook group for different size displays to use as starting points for your own customization.

https://www.facebook.com/groups/Nextion/ 

Getting The Screen To Work with the JumboSpot

Log in to the Pi-Star interface and change a few parameters.

That should be it. Its a somewhat intuitive process to get this working. Any stumbling block may be spent more on picking the right size and manufacturer screen and finding an overlay you like best or making your own. 

Enclosures

There are 3D printed inclosures available on E-Bay for different size displays as well as for those ready made to work with the JumboSpot. 

HVDN Show and Tell

After a few set backs, HVDN is proud to announce we will start having formalized in person meetings later this summer in the Rhinebeck, NY area. There will also be a rotating quarterly lunch or casual gatherings across the Hudson Valley for those who can not make the monthly meetings.

Please become a member (free) for updates on meeting schedules and other events for HVDN

Joining HVDN offers the following benefits

12+ Benefits - Join Now

Basic Digital Voice Infrastructure Round Up (Q1 2018 Edition)

In October of 2016, Steve K2GOG made a presentation at the Overlook Mountain Amateur Radio Club of Ulster County New York at its monthly membership meeting.

At that point in time according to Repeaterbook.com, there were 45 DMR repeaters across all of New York State.

Fast forward to March of 2018, that count has increased to 61 according to the same website.

What about Fusion, D-Star Repeaters in New York?

• D-Star had 29 and is now up to 33
• Fusion had 32 and is now up to 39

What about global growth of digital voice repeaters?

• 2,204 Fusion repeaters (1,431 in Oct. 2016)
• 2,315 D-Star repeaters (2,051 in Oct. 2016)
• 2,326 DMR repeaters (1,493 in Oct. 2016
• 330 P25 repeaters (213 in Oct. 2016)
• 107 NXDN repeaters (82 in Oct.2016

How much growth has there been since October 2016?

• 154% growth for Fusion
• 112% growth for D-Star
• 156% growth for DMR
• 155% growth for P25
• 130% growth for NXDN

With Icom's D-Star being the oldest digital voice technology at 15 years, its days of accelerated growth are unlikely due to a lack of new radio equipment being introduced. The newest radio supporting D-Star is Kenwood's tri band TH-D74 handheld at $550 USD.  A dual band FT-70DR Yaesu Fusion radio can be had new for as low as $199.99. Icom's only current dual band D-Star hand held radio is the $390 ID-51.

There are multiple dual band hand held options from different vendors however for DMR ranging from $86 for the Radioddity GD-77 at the low end and no less than 4 others from vendors such as alinco, Anyone, Aiulence, Retevis and TYT for between $150 to $200.

There are also commercial radios that can be purchased new or at reduced cost for used options for DMR, P25 and NXDN. DMR is the only mode supported by non-commercial radio vendors though.

What about non-repeater use?

Hot spot devices such as the Shark RF OpenSpot, MMDVM based ZUMSpot, JumboSpot, NanoSpot devices and a few others allow users not near a repeater to talk globally. All of these devices are capable to support most all modes listed above and a few able to cross mode translate. This function allows a user to use a DMR radio to talk on D-Star or Fusion networks as an example.

According to Brandmeister Network, there are 5,498 hot spots currently connected to its network which is interesting given that there are only 7,282 digital voice repeaters accounted for globally. Combined, repeaters and hot spots make a very robust communications network for both local and global communications.

Democratized Modern Radio 

Digital voice infrastructure would not be needed if there were no users looking to access it, so a rough conservative estimate is that there should be between 350,000 and 700,000  hand held digital amateur radios in somewhat frequent use globally based on repeater and hot spot deployment figures. That figure is based on the following criteria:

• Number of known registered DMR users
• Number of hot spots currently internet connected 
• Number of repeaters currently internet connected
• Number of repeaters not internet connected
• Number of DMR handheld radio products sold in last 12 months on E-Bay
• Estimated number of D-Star and Fusion users and equipment currently in use. 

Original presentation from October 2016 can be found here

Leave a comment about estimated hand held or combined with other form factors below. 

Using a JumboSPOT via bridged Wi-Fi

On a recent business trip, I left my trusty GL i.Net GL-AR150 at home by accident and could not use my new JumboSPOT unless I used my mobile hot spot feature on my mobile phone to give it the internet access it needs.

JumboSPOT running Pi-Star in DMR only mode

The GL-AR150 is a travel Wi-Fi router which I have plugged in to the ethernet port on my laptop to share its internet connection and create a wi-fi hotspot. This setup essentially lets me take hotel wi-fi and then rebroadcast it so that other devices could use the internet. The laptop essentially acts as a router of sorts in this configuration taking wireless hotel internet, translating it to wired internet and then turning it back into wireless internet.  Make sense?

GL-AR150 multi purpose travel router

Since its always annoying to keep my mobile phone charged up while traveling, I figured it would be a good experiment to see what range too expect from a 10mW DMR hotspot from the 39th  floor of the hotel and out into the city of  Atlanta.  Not having the AR150 with me prevented me from trying this, so I had to find another solution instead of setting up my mobile phone hotspot function, which worked great to make a contact via TG 31368 the previous evening.



Connectify to the rescue!

I found this application named Connectify to do what the hardware I left behind but via software and it works great! It took the hotel Wi-Fi SSID and creates a new access point using the laptop wi-fi to then rebroadcast to the SSID I set up and had in place on the JumboSPOT.

    

   

I would highly recommend the Connectify application to be used in a  travel situation much like I describe above in order to get on DMR with a JumboSPOT.   This is slightly more elegant than the DV4MINI I have used before with my laptop or the GL-AR150 and OpenSPOT combination when traveling. 

Connectify is currently running a 70% coupon on top of it, so get it while you can. You will need the MAX version, not the LITE one. This application will find many more uses aside from just using it to connect the JumboSPOT, which is now my go to device for travel along with the MD-380 for DMR operation. This trip proved a benefit that came out of an annoyance afterall.

An optional, but recommended addition is to also use the "Speedify" VPN application to provide a secure connection and the ability to monitor latency and loss in addition to the upload and download speed reported in the "Connectify" application. Speedify is free for up to 1GB of data transfer a month which seems more than enough if only using this for use with the JumboSPOT.

After about an hour of listening in to a few talk groups with active discussion, only used 3MB of download and all traffic was less than 30ms latency.

http://www.connectify.me/