Wednesday, January 11, 2017

Hacking the Bitx40 with a homebrew Si5351 with OLED Display.

Hacking an earlier version of the Bitx40 to include the Si5351 LO and an OLED Display.


I purchased my Bitx40 early in November 2016 before the "Digi" VFO was available from hfsigs.com. This hack replaces my original hack that used the AD9850 and Pro-Mini I initially installed  with a Nano/Si5351 plus Black and White OLED Display. The code for my OLED/Si5351 can be found at http://www.n6qw.com/Phase7.html  The current configuration of the Bitx40 being offered would obviate the need to build this hardware.

video
 
 
73's
Pete N6QW


8 comments:

  1. That looks very nice.

    Does the OLED generate any noise / interference? The reason I ask,
    I made a DDS for my BITX40 but with a MAX7219 display readout (love the look of 7 segment LEDs). But the MAX7219 generates a lot of interference (have it fixed but it has cost me).

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    1. I have it running off of 8 volt regulator to the Nano and then 5 volts from the Nano to the I2C. This was suggested to me by WA3O. NO NOISE ISSUES.

      Pete N6QW

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    2. I have noise issues a well from an SSD1306 OLED display, I've been trying to isolate it and have hit a brick wall.

      Can you show pictures of your power distribution? A circuit ? I have tried isolating the supply for the Si5351a, the i2c, and the nano. Nothing seem to illuminate the noise which is being generated by the OLED display and injected to the power rail.

      If I run the DDS circuit from USB or a different supply to the BITx, it works great. as soon as the BITx powers the DDS, I get noise when the OLED updates.

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    3. Hi Darryl,

      Rather than take up a lot of space here on the blog contact me at n6qwham@gmail.com and I will be happy to share photos and anything else you want. There are several youtube videos that I have posted with the same set up and you can listen to what it sounds like. Just today I posted a video of the very same OLED/Si5351/Nano that has been reprogrammed for 20M and you can listen to that one. Another place to listen is my blog http://n6qw.blogspot.com. In both cases the Nano/Si5351/OLED are connected to the 12 volt supply through an 8 Volt three terminal regulator. Have you looked at the possibility of grounding issues? Email me and I can share anything your want.

      73's
      Pete N6QW

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    4. Follow on input to Darryl.

      Since I am not sure how you have your Si5351 connected, that may be a possibility. Have you taken VU2ESE's board and rewired it for the OLED or is it a standalone board (as I have done)? Initially I simply connected a DDS to the two pin header and it did not work. Then looking at the Bitx40 schematic I could see that if you connected directly to the hot side of the header you were staring right into the base of the transistor without any isolation. Installing a 10NF made that problem go away. In the schematic for the Si5351 board supplied by VU2ESE there is also an isolating cap on the output of the PLL.[That was a clue to me.] Is there one on the board you installed. I also installed that same cap on the output of my Si5351 board.

      Given the problem clears up when you have a separate supply it is not something inherent with the OLED; but something that is a bypass and/or grounding issue when you have a common rail. So by luck or chance I don't think I am seeing what you are. If you could make a you tube video that may be helpful for further diagnosis. I am not the expert on this so my guesses may be just that. Have you contacted VU2ESE on this issue?

      73's
      Pete N6QW

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  2. Thanks for the feedback Pete. I'm going to buy a few model OLED displays for experimenting. The look nice and are worth a try for future projects.

    73, Lex PH2LB

    P.s. my BITX40 module page on my website can be found at : http://www.ph2lb.nl/blog/index.php?page=bitx40-module

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  3. Pete, could you point me to the details of how to rewire a pre Raduino Bitx40 for use with the SI5351? I have the sketches and displays but need to see how someone else has approached this. The schematic gives me a pretty good idea.

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  4. Actually planning on using a small .96 oled display as an S Meter in my build. So basically dual display and probably also duo arduino(nano) needed. Fun to experiment !
    Regards,
    Leo PD1LDB

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