Kanga UK Resources

Here are some resources supporting hardware available from Kanga-Products UK.


Arduino DDS Shield

"The m0xpd Arduino DDS shield provides a convenient interface between an AD9850 DDS module and an Arduino, opening up the benefits of this flexible “Electronics prototyping platform”. The shield makes the DDS Module easy to configure (through software) and to control (through familiar, everyday interfaces such as Keypads, Displays and Rotary Encoders)".


To make your shield, download the instructions from here

To understand your shield's hardware, take a look at the schematic...


To test your shield, once it is built, download and run this simple sketch ("sketch" is the Arduino name for a program).

The test program, running on an Arduino with the DDS Shield on top, sets up the system to produce a 1MHz output.

 Your shield should draw around 90mA on the 5V supply from the host Arduino...


There's only one adjustment to make; the trim pot on the DDS module might need adjustment to get the shield's quadrature square wave outputs running.

The square wave outputs are on pins 3 & 4 of the "RF Bus" connector, JP1.

Unfortunately, a manufacturing error on the board has mis-placed the labels for the pins - this is how the labels on the corner of the board SHOULD have looked...


With the test sketch above running, connect a 'scope to the sine wave outputs (on the BNC socket, the JP6 header or pins 1 & 2 of the RF Bus connector, JP1) and confirm the presence of the 1MHz sinewave.

Now look at the square wave outputs (pins 3 & 4 on JP1) and adjust the preset until the 250kHz square waves are running.

What if you don't have a 'scope?

Put a short length of wire (10 cm or so) in the relevant pin of JP1 to act as an antenna. Place a receiver, in SSB mode, close to the wire and tune it to 250kHz (plus/minus an audio offset). You'll soon know if there's a square wave there!







Applications

Iambic Keyer for Arduino

Those new to Arduino will find this application a little more instructive than the usual "push a button and light an LED" example - and it might be useful in the shack!

All my keyers support both a straight key and a paddle - as I find it easier to switch to the straight key to change speed or to send a long "dah" for zero, etc.

This is how you need to hook up the Arduino...



Arduino code for the keyer is available here.

Kanga VFO

The m0xpd Arduino VFO system demonstrates use of hardware elements available from Kanga, combining an Arduino (UNO or MEGA), a DDS Module and a display into a system that is both instructive (delving a little deeper into the possibilities of Arduino) and practically useful (you end up with a decent VFO!)...


 

The schematic is shown below...


 

An Eagle schematic file is available here. (Note - there is no board design, nor any intention to produce one)

The Arduino code for the VFO is available here.

Enhanced Kanga VFO 

To coincide with the appearance of the new Kanga / m0xpd DDS Shield, I've put together a second VFO system.


This system is much more advanced than the simpler VFO described above - not just in functionality, but also in hardware...

As well as use of the DDS Shield, the new VFO exploits an I2C interface for the LCD display unit to save on the load on Arduino pins, freeing up some pins to use to support input push-buttons. If you intend to use the display from Kanga UK, you'll find the appropriate software library at this page. If you're using other displays, you must source your own library appropriate to that hardware.

The VFO has three controls; a rotary encoder (with integral push button), used for frequency (and other parameter) inputs and access to the menu system and two push-buttons, used (in normal mode) to change the "speed" of frequency input (the rotary encoder can change frequency in steps of 1, 10, 100 ... 1 MHz) and (in menu mode) to move between the (4) menu categories.

The system supports the amateur bands between 136 kHz and 10m and also offers a continuous "signal generator" mode. There are programmable offsets for each of the five modes (CW, CW(R), AM, LSB and USB) and continuously variable Receive Incremental Tuning (/"Clarifier"). The system can support additive offsets to accommodate an IF stage and has two memories ("VFO A & B"). A hardware input switches between "Receive" and "Transmit" modes.

The system is seen in "Normal" operating mode here...



As you can see, it is made from a stack of Arduino, DDS Shield, Prototyping Shield and an LCD Display (with I2C interface), all of which are available from Kanga UK. Of course, you don't need to use the DDS Shield or the Prototyping board - but it sure makes things simpler! If you're building the VFO into anything more permanent than the experiment described here, you'll certainly want to drop the prototyping shield and mount the rotary encoder, pushbuttons and display into the wall of your enclosure.

In "Normal" operation, the display shows the frequency selected, the mode, the Receive / Transmit status, the RIT offset (above, equal or below the default value for the mode), the VFO selected (A or B) and the band. 

In "Menu" operation, the display format changes - here, for example is the display in Menu 0 (RIT)...



where the RIT value is shown as it is continuously varied. Notice that the "Clarifier" is set above the default 600Hz offset - so the offset status indicator has changed form "=" to "+".

The Arduino code for the enhanced VFO is available here and a schematic of the user interface components is shown below...


[A previous version of this schematic showed the rotary encoder's push-button erroneously connected to A0. Apologies to all those (including Dennis, g6ybc) who were inconvenienced by my mistake.] 

The VFO  is shown above running on an Arduino UNO. It will run on the Arduino MEGA 2560 boards available from Kanga-UK but in this case the display must be connected to the SCK and SDA pins (which are not shared with A4 and A5 on the MEGA).

Kanga VFO 3

A further enhancement of the Kanga VFO code has been produced to support the newly available 20*4 backlit LCD...


The code (which will support both the 20*4 and 16*4 display formats) is available here .

10 comments:

  1. I have complete set of parts and boards from Kanga, build dds shield and wired up display using I2C as in your notes. Clicked on sketch link and went to GIST site, downloaded and untazed the file but there is no extension on file. I then copied text from file and pasted in programmer got lots of errors
    This report would have more information with
    "Show verbose output during compilation"
    enabled in File > Preferences.
    Arduino: 1.0.5-r2 (Windows NT (unknown)), Board: "Arduino Uno"
    sketch_feb25a:159: error: 'LiquidCrystal_I2C' does not name a type
    sketch_feb25a.ino: In function 'void setup()':
    sketch_feb25a:165: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void LCD_Display_Freq(double)':
    sketch_feb25a:395: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void LCD_Display_RiT(int)':
    sketch_feb25a:410: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void LCD_Clear_RiT()':
    sketch_feb25a:417: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void LCD_String_Display(int, int, char*)':
    sketch_feb25a:423: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void LCD_Int_Display(int, int, int)':
    sketch_feb25a:428: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void LCD_Char_Display(int, int, char)':
    sketch_feb25a:433: error: 'lcd' was not declared in this scope
    sketch_feb25a.ino: In function 'void setTxDisplay()':
    sketch_feb25a:473: error: 'lcd' was not declared in this scope

    ReplyDelete
    Replies
    1. Tim
      It sounds as if you either a) do not have the correct LCD library installed (there is a copy of it on the Occam's Microcontroller Software page: https://sites.google.com/site/occamsmicrocontroller/home/software )
      or b) there is some problem with the installation of that library on your system.

      Delete
  2. I had similar errors before installing the LiquidCrystal_I2C library but all ok after installation. .... Except that the display reads 'MHzz' after the value [Cont mode] unless I'm on 10.000000 in which case it moves right and reads 'MHz' ...... then 9.999999 moves left and reads MHzz again. I'm trying to spot a fix but you may already have done this? Nice application BTW.

    ReplyDelete
    Replies
    1. Richard
      Sorry - hadn't spotted this. Can you try adding a space after MHz (inside the inverted commas) in the function call to lcd.print in LCD_Display_Freq() (the first of the subroutines - easy to find). Like this: lcd.print(" MHz ");

      Let me know if it works.

      Delete
  3. That seems ok. Still does the shift right-left but does maintain 'MHz'. Thank you.

    ReplyDelete
    Replies
    1. Great - can you tell me which program we're talking about - and from where you downloaded it.
      I'll fix the source.

      Delete
  4. I'll keep a closer eye on this comment .... not sure the previous one got there.

    Can I alter the values 4294967295/125000000 to shift the frequency slightly? I guess that the first part is the maximum division ratio and the second value the TCO frequency?

    ReplyDelete
  5. Ok ... previous comment didn't go properly. It said that the code came from the link on this page to GitHub Gist m0xpd / Kanga VFO 2 [see line 400].

    Also, similar extra z or zz when RIT reduced .... not a big issue.

    Also seem to be 0.001% low in frequency compared to my frequency counters .... which may need checking!!

    ReplyDelete
    Replies
    1. Richard
      Please can you contact me by email (see QRZ.com).
      We'll deal with this outside the "comment" framework and then share outcomes publicly.

      Delete
  6. OK ... last comment .... guess my TCO is running a bit slow .... changed 125000000 to 124998750 to get the o/p frequency in line with my counters. Off-air standard for me next then ??

    ReplyDelete