Check out this youtube description from KJ5VW of his µBITx modifications.
Jack W8TEE and Al AC8GY have been working on a display replacement for the µBITX for quite some time. They now have a preview video that gives an overview of the JackAl system.
There are some software hiccups in the preview that should be fixed soon. We just sent Rev 4.0 of the JackAl board off to the PCB fabricator. They hope that this will be the final version of the board. All SMD’s will be included on the board.
JackAl makes use of either 5″ or 7″ 800×480 displays (US$34-$44) using the Teensy 3.6 microcontroller (US$30) and its companion audio board (US$14) for the DSP.
The Teensy has 1Mb of flash memory and 256K of SRAM, or which they are using less than 20% and 15%, respectively. Jack and Al have also brought out a dozen “empty” pins for experimentation, so along with the I/O pins, there plenty of resources left to play with.
Pay particular attention to the ALS Tuning it uses. It really makes it so much easier to zero in on a station. Details are all in the video.
W0EB’s uBITX is built with a 5″ RA8875 type Color TFT display connected to a BITeensio Card. This gives an “uncluttered” display.
This version of the BITeensio TSW firmware is almost ready for release. It is just awaiting completion of the accompanying instruction manuals and the arrival of a small adapter board for connection to the display. The adapter boards will be supplied in the BITeensio kits upon request.
This display, like the previous 2.8″ Colour touch panel display and the 4 Line I2C display (2004) are capable of utilising an optional external USB Keyboard for rig control and CW. The W2CTX RCP (Remote Control Program) works with this as well.
For information and updates see the TSW website.
Jim W0EB is working on a 2.8″ touch panel for the triumverate’s BITeensio. That will make four different alternative touch screen options for constructors: VU2SPF Mega2560 attached 2,4″ LCD (first up way back in January), KD8CEC Nextion screen (in a range of sizes from 2.4″ to 7″) , BiTeensio 2.8″, and the long awaited JackAl (in 5″ and 7″ sizes).
Some of you are waiting with baited breath for the JackAl Board, announced by Jack W8TEE. You can get yourself geared up for the JackAl by pre-purchasing some of the kit required, as it is due to be released shortly. You will need a colour touch display panel, a Teensy 3.6 processor and associated Teensy audio board.
There are two display options for the JackAl board: 5″ or 7″. Neither is likely to fit in your existing µBITx enclosure, so you may also want to purchase a new enclosure.
The panels can be purchased from BuyDisplay.com. Their order numbers are:
Both displays use the following options:
4-wire SPI interface
No font (the library is being used for fonts)
Both are 800×480 displays using the RA8875 chip. If you run the samples using a touch screen, make sure you run the Calibration sample program first.
Teensy 3.6 and audio board
The Teensy 3.6 and its associated audio board can be purchased from the manufacturer’s website or from other sources.
Ian KD8CEC has been looking at power consumption on the Nextion display and how to effectively dim the screen for portable µBITx work, where you want low current drain.
The following picture show’s Ian’s display (2.8″ TJC Chinese version) at Full Power:
And the screen fed with a series 50 ohm resistor (1/2 watt rated or more):
The slightly dimmer display halves the current consumption from 89mA to 44mA with a series 50 ohm resistor (made up of two 100 ohm resistors in parallel (or 3 x 150 ohm resistors in parallel). The Nextion screen has a built in software dimming function, and this can be adjusted in Ian’s Nextion display firmware. However, the feature generates noise in the µBITx and is not recommended.
Installing a series resistor (with a value between 20 ohms and 100 ohms) in the +5V power lead will cause the display to be dimmed, but function normally (except for use of the micro-SD card reader). The resistor could be installed across a slide switch or toggle switch (with one pole shorted and the other going through the resistor) to allow for two settings (normal, dimmed). This could be handy for night time or portable use. The circuit diagram for this is as below:
For further details see Ian’s website.
Michael VE3WMB brings us some hints when installing Nextion displays:
1) The Display wants the microSD card to be formatted as FAT32. Make sure your microSD card is no larger than 32GB
The default in Windows is to format cards > 32 GB as exFAT, which the Nextion will not accept. In fact Windows 10 probably won’t even let your reformat a card this big as FAT32. (I am sure if you dig deep enough there might be a way to do this. I am not a Windows GURU).
Currently you only need a 2 GB card, so if you need to buy one for this purpose try an 8GB card. It is also worthwhile buyong a brand name card (like Sandisk).
Some no-name cards are slower than cold molasses to read from and write to.
2) If you have a problematic microSD card, when you power up the rig you might not see anything on the display, not even a backlight !
I spent considerable time trying to solve what I thought was a wiring/power problem to the display when it was a bad SD card. When the I removed the card and power-cycled the rig the Nextion display came up fine with a demo program that was already loaded. So my recommendation is for the initial power up of the display don’t insert the SD card. That way you can be sure that you have it wired up ok before you start messing with SD cards.
3) Beware, ground and +5V connections on the Raduino going to the Nextion Display are adjacent to each other.
I recommend that you check and recheck your wiring several times before applying power. It is very easy to accidentally swap these and you won’t be happy if you do. As they say, “An ounce of prevention is worth a pound of cure”. One group member has already found this out the hard way.
Mark AA7TA adds:
4) Duplicate .tft files (including hidden files) will cause grief on the Nextion
You may get a message on the display that the load failed because there is more than one .tft file on the SD card. This can happen even when you look and you see only one file.
You need to be sure to enable viewing of hidden files in file explorer (Windows) or finder (on a Mac)… There’s probably one hiding there with the .tft suffix that you need to delete. I don’t think either operating system will show hidden files by default. The same goes for Linux.
Mark notes that a 1G SD card is plenty big enough for the current tft file.
Keven adds, “Linux doesn’t show hidden files by default. But you can see them by typing:
in a terminal window when you’re in the directory you want to examine. To hide a file, rename it with a dot (‘.’) as the first character.”
Mike ZL1AXG adds:
5) Make sure you install the screen the right way around
Power up the display before you start making holes and check the orientation of the display and that the screen is functioning correctly. As with the 16×2 display, it is possible to install the display upside down by mistake! Given it is not symmetric (there is a wider bar to the right hand side of the display) care is needed! The inner silver line on the screen defines the touch sensitive boundary. Cut your hole so that the screen fits so the line is just visible around the outside edge.
Dimensions of Nextion displays can be found for this zone on the itead website. Click on your display and near the bottom of the page you will find a link to the screen dimensions.
6) For most people the 3.2″ screen or larger will be best
A 3.2″ screen is only just big enough to feel comfortable for us fat-fingered chaps. It is also just wider enough to reuse the width of the 16×2 screen. Smaller screens inserted in the space where the 16×2 screen currently lives will require an additional aluminium or plastic plate to be added to the front panel to cover the existing width of the 16×2 screen.
Some of you will have been sufficiently observant to notice that the graphic at the top of the www.ubitx.net webpage has been updated. This is because Mike ZL1AXG has installed a Nextion 3.5″ touch screen on his own µBITx. Careful work with a drill and file will yield satisfying results.
He also installed the latest pop fix from the v4 board (see the separate article).
Lowell has tested current draw on a 2.4″ and a 3.2″ Nextion display following questions from constructors over the likelihood of cooking the existing 5V regulator. With a supply voltage of 5.04 VDC, the 2.4″ display drew 125 ma. and the 3.2″ display drew 110 ma. Both displays were at full brightness. While the figures are slightly above those listed on manufacturer’s website, this suggests the 5V regulator should be fine. If in doubt, add a heatsink!
Ian Lee KD8CEC has released Beta firmware for the µBITx that supports Nextion colour touch screens . He has also released matching files for installing firmware in the Nextion displays for 2.4″ and 2.8″ screen sizes. No programming is required to use these displays.
The photo above shows the touch panel display. Pressing on the screen will perform functions like changing band (up/down), changing frequency, adjusting the Attentuator (ATT), IF Shift and RIT, and going into Split mode.
See Ian’s webpage for details about downloading the various firmware options along with detailed instructions.