Small Footprint HL2

[Pete Juliano]

Recently spotted a nifty 3.5 inch Color TFT diaplay that plugs into an RPi4 or Rpi3. This is a product sold by TreeDix on Amazon. For about $23 you get a case (RPi4) an inetrnal cooling fan for the RPi4 and the Display. 

I installed the display on a Rpi3 running QUISK that can either run the HL2 or Softrock.

If you are cramped for space this is a really small unit that combines the Pi and the display all in a very small box. By picking the right resolution you can have the entire screen displayed and the BONUS -- it is a touch screen and comes with a stylus. This might be ideal for a travel or portable rig. 

Yes Virginia not only is there a Santa Claus but that is QUISK on a 3.5 Inch Color TFT

73's

Pete N6QW

[Steve Haynal]

Hi Pete,

Thanks for sharing the link. It all looks very interesting. 3.5 inch is the smallest screen I've heard of used with Quisk. Do you still find it pretty usable?

73,

Steve

kf7o

[Heath Petty]

I have one of those small screen. The issue I run into is unless I run the display at its native resolution (iirc something like 320x240), the touch screen mapping is not correct ( I cannot reach the edges of the screen). I run mine on a pi3 but with a virtual resolution of 640x480, but i have to use a mouse (or connect to it via VNC) to be able to click everywhere on the screen. I have been considering getting a 10" touch screen to go with my pi4, for some mobile operation.

Heath

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[ron.ni...@gmail.com]

IMHO, PC user interfaces need to be completely redesigned to be reasonably usable on small (3 to 5 inch) touch displays.  Is Quisk's control interface abstracted in a way that might allow porting to a completely different UI paradigm?

73,

Ron

n6ywu

[Phil Erickson]

There seem to be a number of 7" screens for Pis.  I wonder if that is enough real estate for Quisk mobile without having to fuss too much?

73

Phil W1PJE

[Steve Haynal]

Hi All,

For those interested in small screens and portable use, another option is to port some of the efforts for SDR on MCU to work with the Hermes-Lite:

https://github.com/DD4WH/Teensy-ConvolutionSDR

https://github.com/df8oe/UHSDR

https://groups.io/g/keithsdr

I'm sure there are others. One reason I picked the more-powerful-than-needed teensy for the keyer project is because of the crossover MCU which could be used for a standalone SDR. One could combine a $4 RT1011, $6 FPGA, and $30 AD9866, screen and i2s audio into a nice portable Hermes-Nano project...

73,

Steve

kf7o

[N7IHQ]

The Raspberry Pi 7 inch screen (800 x 480 resolution) works well with the Quisk small screen button layout configuration.

Jim, N7IHQ

[K7MDL]

FYI, I wrote the KeithSDR variant with High Res spectrum/waterfall on the Teensy 4.X and PJRC Audio card.  It works on both the 4.3" RA8875 based, and 7.0" RA8876 based touchscreen displays with lots of CPU cycles left over.  It is only RX today though has the infrastructure for TX features/control. Been waiting for suitable QSE TX hardware.  Decided to try using the HL2 instead.

I added a PanAdapter mode that is currently optimized for the Elecraft K3 since that is what I have, using the serial COM port.  I have been moving toward making it a full control head for the K3, FT-817 and likely others.  

K7MDL2/KEITHSDR: Teensy4.X with PJRC audio card Arduino based SDR Radio project. (github.com)

I recently received my HL2 and have been looking at C code examples to implement the openHPSDR protocol 1 on the Teensy's ethernet.  Seems doable given some quality dev time investment.  I am envisioning making my Teensy SDR a control head for the HL2.  The handoff of the audio from the ethernet stream to the DSP is a mystery to me, but I figure I will get the control aspects working first and sort out the audio afterwards.

We are using the OpenAudio_Library, converted to 32bit Floating point recently by Bob, W7PUA.   Running 4096I+Q FFT today no problem at 104KHz sample rate.  

I and a few others are looking forward to making this work on the HL2.

- Mike

K7MDL

CN88/EL87

[Steve Haynal]

Hi Mike,

Sounds very interesting. I think there is a lot of interest in a self-contained and portable HL2-based radio with no need for a host computer. Although ethernet connection is possible, another alternative would be to connect to the HL2 via a QSPI interface. There are 5 IO pins on the FPGA which could be used for this. I'd setup the HL2 to appear like a memory device. Then from the Teensy you would periodically read data out and write control as if it were standard QSPI-based memory. This would enable permanent embedding of the Teensy for portable use, but still allow host-based use via the ethernet. It would also allow us to expand and simplify IO. For example, with the Teensy's UART. 

73,

Steve

kf7o

[K7MDL]

Interesting, I am game.  I will study QSPI.  

keit...@groups.io | Changes on GitHub SDR-RA8875 has a history of the UI framework, pics, and relatively standalone spectrum/waterfall feature which is configurable for size and location (data driven config).  

- Mike

[Steve Haynal]

Hi Mike,

Okay. I will look around for a ready made QSPI or SD card emulator for FPGAs. Maybe having the FPGA emulate a SD card would be more useful as SD card libraries may be more common place. 

This is something I've always wanted to do, but I am pretty bogged down with my day job and other projects, so it may not happen soon.

73,

Steve

kf7o

[K7MDL]

SD card is easy from the Teensy perspective.  I am using one now to store and retrieve the configuration tables.  Compared to my progress the last 2 months, I expect to be moving slower this summer as I expect to return to some part time work.  I am retired so normally have all day, but when I am at my northern QTH near Seattle in the summers, I am working part time.  

The audio card and the Teensy 4.1 both have SD cards readers installed, both on a SPI bus, and the RA887x display is also on a SPI bus, but that display is not tri-state, so without extra hardware, does not share it's bus. Will have to look at connections and addressing.  My latest build has the Teensy 4.1 and audio card stacked and mounted on the back of the touchscreen display to eliminate a flexible SPI bus cable previously used that slows down the max bus speed (due to length) and is a source of RFI noise, even shielded with copper tape.  Some of the group are working on a PCB motherboard that mounts on 2x20 display connector and should fit behind both the 4.3" and 7/10" displays.

- Mike

K7MDL