Teensy audio board schematic and simplified audio “board”

Dr Flywheel (aka Ron N7FTZ) has provided some details of the Teensy audio add-on board.  This is used in the upcoming JackAl add-on board expected to be available shortly, but can almost certainly be home-brewed by savvy constructors using the Teensy 3.6 and audio add-on board.

Here is the circuit diagram for the PJRC audio module:

The CODEC part is very much the reference design provided by the part manufacturer. The support for the EEPROM and the SD card is optional.

The libraries will be compatible with any SGTL5000 or for that matter a long list of other I2S compatible CODECs (look at the source code). If you are homebrewing an audio processor on the Teensy you should consider integration of the CODEC. The libraries will support the internal A/D-D/A of the Freescale ASIC with very few components (resistors, capacitors) added.

Sample resolution of 12-bits is sufficient for the type of audio DSP that we need, though the higher bit-rate CODECs are much better. It is a matter of cost effectiveness and board space.

An alternative simpler approach

 

Below shows mono circuits for a lower grade Teensy, however the circuit is the same for the Teensy V3.6 with the corresponding pins.

The input circuit (mono):

Here is the output circuit (mono):

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Video on the JackAl system

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.

https://vimeo.com/290318066

New release of VU2SPF firmware v3.1cU now available

A new version ofSP Bhatnagar VU2SPF  firmware for the low cost MCUfriend TFT with Touchscreen based VFO + BFOs is out now along with an illustrated manual.

This version (3.1cU) provides the following new features:

  • a row at the bottom to set / adjust both BFOs
  • PTT type selection (Toggle or Normal)
  • auto Time out duration setting
  • individual offsets for each band
  • Touch Sensitivity
  • Lower and Upper limits for displays of S-meter and Power meter.

It continues to provide:

  • 3 VFOs (A/ B and Memory -100 channels)
  • Direct Band selection
  • LSB/USB setting
  • Setting the frequency change step size from 1 Hz to 1 MHz
  • exchange of frequency between VFO and Memory
  • saving all parameters on demand
  • split frequency operation
  • auto band Up /Down scanning and CAT control

This system uses a standard Arduino Mega board with compatible MCUFriend type TFT / Touch shield and either a standard Si5351 breakout board or one designed specifically for it to replace the Raduino board.

This combination makes it very simple to assemble in a short time.

Please note that this system is only for experimenters who have some practical experience with Arduino and the relevant hardware and are keen to learn. There is no ready-made kit as of now and all information is already available on our blog and on Github.

If there is someone willing to kit it for ham friends Raj would be only too happy to assist.

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Further details on Nextion Display and second arduino

Ian KD8CEC, in his third article on using a second arduino with the µBITx, demonstrates the signal scope feature made possible with having a dedicated ardunio nano connected to the main Raduino control processor via i2c lines.

The signal scope shows a section of the band surrounding the currently tuned frequency IN REAL TIME.    The nano and the serial connections to the Nextion doesn’t have the agility to provide a full blown waterfall display, but a real time display of signals around where you are currently tuned is still pretty impressive.

The other feature that is present in the Nextion display version of this arduino add-on, is a CW decode function.

Bring on the release of v1.097 of CEC firmware!

Another Raduino Replacement – this time with a Blue Pill

Joe W3JDR is working  on a  Raduino Pill board which is a direct replacement for the stock Raduino, but with an STM32F103 processor and much more I/O. I think it hits all the points on your wish list. I released the PCB to fab a few weeks ago and am waiting for boards to arrive from China. Assuming it functions without major rework, I’ll post the CAD files and Gerbers on my web site and encourage others to develop for it. I plan to immediately mod the stock uBITX firmware to run on it, then will expand functionality to incorporate the work I’ve done with TFT displays, hi-res encoder and software S-meter & AGC. I’ve cleared my bench in anticipation of arrival and am checking the mailbox every day.

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Getting prepared for the JackAl

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.

Display panel

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:

ER-TFTM050-3 (5″)
ER-TFTM070-5 (7″)

Both displays use the following options:

4-wire SPI interface
3.3V
Resistive touch
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.

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Warning for those using a Teensy 3.5 or 3.6 or Biteensio board


Jim Sheldon, W0EB notes that the tiny power jumper on the back of the Teensy 3.5 or 3.6 MUST be cut when using external power to the Teensy (from the BITeensio board). Left intact, it is possible to have power being applied to the Teensy through BOTH the BITeensio board AND the USB connection, especially during programming or remote control operation via the USB port. This may cause board power and USB power to conflict with each other and can destroy the Teensy.

The jumper is pointed out on the back side of the pin-out card that comes with every Teensy and it states: “Cut to separate VIN from VUSB, if using a battery charger or external power.” with an arrow pointing to the jumper between the two pads.

Carefully cut this tiny jumper with a very sharp hobby knife to avoid any possible problems.  After cutting the jumper, you will have to power the board externally through the BITeensio card (or other means) when programming or re-programming the Teensy through the USB port.  This holds true for Teensy boards used in just about any application, not just on our BITeensio board.

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Latest release of the TFT Colour Touch Control from VU2SPF and VE1BWV

VU2SPF and Joe VE1BWV have released the latest version of their TFT Colour Touch Control.

PROJECT HIGHLIGHTS
Low cost, standard easy to get parts, Colour, Touch Control and any combination of Touch Control or physical buttons.

TFT (Touch) Display module, Atmega 2650, Si5351 DDS, 1 UBITX and a few wires = All Band rig with Computer / Radio Touch Control Colour Display.

Some new features:

  1. Automatic Scanning – up to band edges in both the directions is now added in V2.9bU of software. The scanning allows one to find signals of interest across the band. Two small buttons labeled ‘U’ and ‘D’ scan in up and down directions from the currently set frequency. The scanning can be stopped by touching the frequency display area.
  2. CAT Control  – the software now has new code to emulate FT817 Cat commands… This provides radio and computer control for the digital modes.
  3. User Manual   A new comprehensive user manual has also been added. Various users and new builders have been looking for this for quite a while.The new version is available on Github at : https://github.com/sprakashb/TFT_TouchScreen_for_uBitxInfo also available at:
    http://vu2spf.blogspot.ca
    https://www.youtube.com/watch?v=zkg-IrjV2h4&t=375s

(UBITX ver2.9bu Installation Results)

Note that at present the firmware doesn’t support CW.

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JackAl is here!

Jack W8TEE and Al AC8GY have  released details of the JackAl board following FDIM (preceding Dayton Hamvention).

Friday night is a sort of Show-and-Tell at FDIM and they used that opportunity to show their JackAl board in action. The photo above shows a little more about what it is and does.

At the show, Al hooked up a noise generator to the µBITX to show how the filters work. (There are 4 preset filters for CW and 4 for SSB.) In addition, you can customise one CW and SSB filter to the bandwidth you desire. You might be able to see that the skirts are pretty steep for the filters on the scope in the background. The setting of the CW custom skirts are set differently, in that you pick a centre frequency (e.g., 700Hz in the shot below), press the encoder, and then you see this:

In this case, turning the encoder CCW increases the bandspread (i.e., the 440 red number above, although it looks orange in the photo) by simultaneously moving the skirts (480Hz and 920Hz) further apart. If you turn the encoder CW, you narrow the bandspread. Most CW users will probably center the bandpass on their favorite sidetone frequency, which centers the bandpass on that frequency.

The demo used a 5″ display, although a 7″ display is also available. The third knob on the front is for a second encoder that we use for everything from setting the CW keyer speed to adjusting the filter skirts. You can see some of the plots on the panel at the rear of the picture above for some of the board’s features (e.g., filter responses, compression, etc.) Those will be included in the documentation when the (downloadable) manual is finished.

The JackAl board has the following features:

  • 5″ or 7” touch screen 800×480 TFT color display
  • Dual VFO’s
  • RIT
  • S meter
  • RTC
  • CW keyer, 5 to 50wpm (we could go up to 100wpm, but…really?)
  • Up to 50 CW preset messages, selectable at runtime…perfect for contest messages
  • Touch screen function and control selection (e.g., band changes, RIT, mode, VFO, VFO increment, LSB/USB, etc.)
  • Automatic LSB/USB selection based on frequency (overrideable)
  • One touch frequency increment changes (1Hz to 1MHz in multiples of 10…the white underscore in the frequency window)
  • Dual encoders (frequency, features)
  • EEPROM storage of user preferences (one-click reset to “factory” defaults)
  • Uses Teensy 3.6 processor (1Mb flash @180MHz) and companion audio board
  • Support for 3 external CW push button switches (NO) for sending stored CW messages (e.g., contesting)
  • Hardware AGC using IF take-off
  • Audio AGC with adjustable threshold
  • Mic compressor with adjustable threshold
  • 8 band audio equalizer
  • Receive audio filter: 48dB/octave (8 pole equivalent DSP filters)
  • 4 CW presets (150, 300, 400, 600, [or none] Hz 3dB bandwidth) + 1 user-defined knee frequencies (at runtime!) filter
  • 4 SSB presets (1500, 1800, 2200, 3000, [or none] Hz 3dB bandwidth) + 1 user-defined knee frequencies (at runtime!) filter’
  • Variable Notch filter, encoder adjustable, use specified Q
  • 7 watt power amplifier

The board will be distributed with all (surface mounted) parts in place. The user must supply the Teensy 3.6 ($30), its supporting audio board ($15), and the 5″ ($34) or 7″ ($44) touch screen displaying (using the RA8875 controller chip, BuyDisplay.com).

We expect the JackAl board to sell for $50.

We may need to adjust this price as we have only received “ballpark” cost estimates for the board since we only have the Gerber files for the Beta board.

Currently, we are using less than 20% of the available flash memory (out of 1Mb) and less than 15% of the SRAM (256K), so there is plenty of memory resources available for adding “stuff”. The board also brings out a number of I/O pins to help your experimentation. With the exception of removing one SMD resistor on the µBITX board and soldering two wires to those pads, all interconnections are via existing connectors.

Our best guess is that after finishing the modified Gerber files, production, Beta testing, and writing support manuals, it will be probably two months before we begin distribution. We will announce its availability here as soon as we can. BTW, if anyone knows a high-quality PCB manufacturer who also does pick-and-place at reasonable prices, we are getting quotes and would like to know about them.

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W8TEE JackAL Board at FDIM

Jack W8TEE provides a bit more insight into the JackAL board that uses the Teensy 3.6 to give lots of processing grunt.

Jack suggests that he and Al were going to put an SWR meter on the JackAl board, but have backed away from it for this iteration. The main reason was because of the board size. The nano-acres it would take on the board would raise the PCB cost above the 100x100mm size to do it right for the possible power levels that might be involved. That doesn’t mean you can’t add one…

The good news: Right now, there are about a dozen “empty” pins available on the board for experimenting.  They are currently using less that 15% of the 1MB of flash memory and less than 10% of the 256K of SRAM.   That includes code space for some features that we’ve coded for (e.g., a RTC) but have not implemented yet (e.g, adding a button battery to power the Teeny’s RTC in sleep mode).

The Teensy is a 3.3V device, so we have an onboard regulators for 5V and 3.3V. Al and Jack think this will up the “fun level” for hackers considerably…at least that’s our intention.

The bad news: They got caught in some kind of Chinese holiday and other “delays” to get the PCB. Al ordered the board since he did all the work on the EE design. It seems our Beta PCB order got pushed to the back of the line.

When Jack wrote to them and pointed out that he was disappointed with their service, especially after ordering more than 1000 boards from them last year, the order suddenly went from “In line” to “shipped” in under 24 hours. They received the board this week and discovered errors on the board (2 from the design team, 1 from the manufacturer of the board).  The Beta board will have some “hairs” on it.

Jack and Al will be demoing JackAl at FDIM, but not all of the features will be implemented. The order for the new board will be sent this week.  We’ll immediately send it to our Beta testers and then make it available via an announcement on the BITX20 list.

Al and Jack look forward to seeing uBITx constructors at FDIM!

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