TS-520S VFO using the Arduino Nano VFO board. Then a custom PCB.

VK3ZYZ

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I had to install a pre-regulator as the Arduino reg was overheating.
This is a little switch mode reg set to 7V out. The PCB will be modified to add an external 7805 to drive the 5V so to bypass the Arduino regulator.
View attachment 2583
When I finish the testing, I'll clean the PCB. It looks pretty crook!
Latest circuit...
1720612821706.png
 

BillC

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Nice work Denys. The matrix of 66 holes in the lower right hand quarter of the board, is that used for possible future mods.or sub circuits?
 

VK3ZYZ

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Yes, as this is a proto board, I filled the spare space with hole for "Justin Case".

A second version to add a 7805 external reg may get made as the Arduino internal reg is not up to the load.
This is a change from the one that was posted here a couple of days ago.

1720846957538.png


This one will run as a counter when not being the VFO. My proto tests seems to work ok so now it is just a matter of getting boards and tiding up the code.

EDIT! I need an extra divider chip as the Arduino counter cannot keep up with the frequency.
Another EDIT: Version 3 board will be coming soon as this has errors. See below.
 
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VK3ZYZ

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1721823240625.png

The circuit is a bit hard to read so here too is a .pdf.


EDIT! I needed an extra divider chip as the Arduino counter cannot keep up with the frequency. so this is updated 20240724.
 

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VK3ZYZ

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Oh well, I have placed an order for the PCBs so let's hope they are ok!
EDIT! The V2 board had an error, besides needing a second 74163 divider. I did the classic of hooking the 5V reg up backwards so killed another Arduino, Si5351 and LCD :(
 
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VK3ZYZ

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I had a bit of fun this AM. While hooking up the proto system to do a test. "something" went wrong. (I do not know what) but there was quite a flash and bang and a Tantalum capacitor let its smoke out with enthusiasm.
.
Photo on 17-7-24 at 10.05 am.jpg

It looks like now I have another dead Nano, Si5351 and OLED display :(
 

VK3ZYZ

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I have the Version 2 boards here now. Unfortunately, as mentioned earlier, there is an error so the second 74163 quad divider is mounted on top of the other.
Second75163_1.JPG
Pin 2 of the top one connects to pin 15 of the lower one, and that has pin 15 isolated from the PCB.The top divider has its pin 15 connected to the PCB. The top one also has pins 11,12,13 and 14 cut off.
All pins other than mentioned above solder to the same pins of the lower one.

Second74163_2.JPG

At the house wrecker's yard I picked up some 80mm x 40mm Aluminum extrusion for the case base. It has an extra strip running down the center that has to be cut out.
Mounted_1.JPG
The 7805 reg is bolted down to this case for heat sinking.
Mounted_2.JPG
Then a hole is cut for the USB lead used in programming.
Mounted_3.JPG
My metalwork is pretty rough.
A 3D printed top will be made later, and I think the base will have to be a bit longer than I've made this one.
 

VK3ZYZ

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The battle continues!
I've just assembles yet another board, swapping the 5V reg around and testing it produces 5V BEFORE adding the other parts.
Then, installing the Arduino Nano and Si5351 board.
Next trick, I could not program the Arduino. So, with a bit of effort, the Arduino was removed. Another was opened and tested before soldering it to the PCB. It too would not program. Closer inspection revealed one of my Arduino Nano orders was filled with 168 chips, not 328 versions. So, they will program correctly when selected but there is not enough memory for my application. I've never ordered the 168 boards (checked the Ebay orders) but the problem is I do not know who was the supplier of these boards. I may order some chips to replace them but the chips are almost the same cost as a full Nano.
 

VK3ZYZ

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NOTE: This is no longer valid as of 20240806. It would need to be modified to suit changes made for the Arduino Nano version as shown in post #43.

(old entry)
I'm thinking of changing to a Blue Pill STM32 board in place of the Arduino Nano as it is faster and has more memory.

1722039015082.png

It will be a change for me as I've not used them before to any extent.

1722039099146.png

Maybe Josh can help with programming ;)
Growing one onto an existing board will not be to hard as there are not that many connections so it will be interesting to see if I can get it working at all.
 

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VK3ZYZ

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Yes, with some changes to accommodate the hardware differences.
For some reason, I don't know why, they seem to not like programming via the USB connector but need an external USB to serial adapter and it turns out the encoder connector on the proposed board is suitable as the programming connector also. (That was accidental but nice)!
BUT!!! I think a redesign is needed to allocate the pins better. This was just done to suit the PCB and not the hardware.
 
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VK3ZYZ

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It now runs on an OLED display. This is my latest development setup. Still the Arduino Nano version.
Photo on 31-7-24 at 8.24 pm.jpg


Photo on 31-7-24 at 8.23 pm #2.jpg
Photo on 31-7-24 at 8.23 pm.jpg
 
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VK3ZYZ

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The latest code, mostly working, at least as just a VFO, and one line commented out will change from LCD to OLED display.
1722474304972.png

Also, an easy way to swap the encoder direction.
 

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VK3ZYZ

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Photo on 2-8-24 at 12.53 pm.jpg
I've linked the RCA HET signal to the unused pin 7 on the 9 pin socket so just one cable can be used.
 

VK3ZYZ

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It is almost there:
Photo on 5-8-24 at 4.48 pm.jpg

This is the VFO reading the set's internal VFO listening to 7.11Mhz :)
The code needs to be streamlined a bit as it is slow now.
Also, when switching between bands and int/extVFOs, the old frequency is not remembered to go back to.
 

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