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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Wed 03, 2017 3:49 pm 
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They look very well made. With a bit of luck, you will be one of the people who DID get the design right first time! Keeping my fingers crossed for you.

Colin


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Wed 03, 2017 4:36 pm 
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Location: Benton City, WA
louhaskell wrote:
They look really great. From the appearance, the quality is amazing.

AT $25 for 5 boards, I can afford to tweak the design and resubmit if needed.

Image

Lou, I would also like to order a board when available.

I am on another list that is building an antenna analyzer. They also use a AD9850 DDS module. Because the designer used the dual row one end, single row other end header people are having a very hard time getting the module that matches that footprint. Many are buying them on ebay from Chinese sellers that show the correct footprint module but in over 95% of the cases ship the other footprint (single row headers on each side). Which module are you specifying? Specifying the vendor might not get the correct module even if their add shows the one you want.

Just a heads up.

Jim


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Wed 03, 2017 4:55 pm 
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Jim:
I have seen that other version of the AD9850 module board. I decided to spend a little more and get one off of Amazon. Costs $17 but I am a Prime member so it comes in 2 days with free shipping. Here it is:
https://www.amazon.com/gp/product/B0085N592S/ref=oh_aui_detailpage_o09_s01

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Wed 03, 2017 6:38 pm 
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Location: Benton City, WA
louhaskell wrote:
I have seen that other version of the AD9850 module board. I decided to spend a little more and get one off of Amazon. Costs $17 but I am a Prime member so it comes in 2 days with free shipping. Here it is:
https://www.amazon.com/gp/product/B0085N592S/ref=oh_aui_detailpage_o09_s01

The one you are buying and spec'ing is the same footprint that everyone is receiving from ebay and Amazon sellers even when the other footprint is shown in their product listing. As you can see, the footprint is different. Some of the AD9851 modules have the other (dual header one end and single header at other end as opposed to single headers on each side like the one you used).

What would be the advantage or disadvantage to using a AD9851 module as I see the prices are now about the same as the AD9850 modules.

Thank you.


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 04, 2017 12:46 pm 
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I had looked at the AD9851 modules which, at the time I looked, were more expensive than the AD9850 modules. Upon reviewing the specs for both, I do not see an advantage of using the AD9851 module. I think the basics of using the FET to do AM modulation plus the flexibility of using 2 modules to do a wide range of sine and square wave generation would be the same. If you have further info on the AD9851 or I am missing something, please share.

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 04, 2017 2:20 pm 
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Well, as they always say - good news and bad news .
I was able to populate the board with the components although there were several problems. In some cases, I used the built in component physical dimensions provided for some components. For some of the capacitors, the hole leads were too small so the holes must be specified larger. I incorrectly specified the holes and placement for the tabs on the pots. But my biggest snafu was the spacing of the pin rows on the DDS modules. I was off by a whole row or 0.1"! I must have counted the rows while the module was in the breadboard and forgot about that gutter in the middle that separates the 2 interconnected sides. Big problem. But I was able to mount some tall headers with "legs" spread to get the extra 0.1 inch and get the modules mounted so I could do electrical tests.
And that is the good news. The darn thing works! All of the functions and outputs are working on the 5 BNC connectors. So I have a functioning board to use for now. I can use this for further tests and for alignment as needed. And since my mistake on the DDS modules and other mistakes will not affect the enclosure, I can move ahead on that with my friend and his laser cutter. I will make the changes to the board, check that about a hundred times, and send off to China for more boards. Live and learn.

Image

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 04, 2017 3:04 pm 
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Well done Lou! It looks very professional.

Colin


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 04, 2017 3:42 pm 
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Way to persevere!

Very impressive, Lou.

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 04, 2017 5:23 pm 
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Congratulations!

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many of my radios http://s269.photobucket.com/user/FSteph ... t=3&page=1


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 04, 2017 6:29 pm 
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Great job Lou! I can't wait to see the final version.
Bill

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Fri 05, 2017 3:03 am 
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louhaskell wrote:
For some of the capacitors, the hole leads were too small so the holes must be specified larger. I incorrectly specified the holes and placement for the tabs on the pots. But my biggest snafu was the spacing of the pin rows on the DDS modules. I was off by a whole row or 0.1"!


Before fabricating the board, as a safety check, it's a good idea to print out the PCB pattern on paper, actual size. Then, place your components onto the printout, to make sure that all the parts fit the way they are supposed to. I've caught a number of errors this way over the years. Sometimes I've had situations where the solder pads were spaced correctly, but the components themselves had enough overhang that there was interference between adjacent components.


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Fri 05, 2017 12:17 pm 
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The board has been fixed up in EasyEDA and resubmitted for the next (final I sure hope) iteration of the circuit board. Will have to wait another 3 weeks for the boards to arrive I am sure.
Thanks for all of the kind comments on this. It has been a fun project. Hope to post some photos in the coming weeks of my attempt at a nice enclosure for this. And in the meantime, I can continue working on the cabinet for my Zenith 6S52. Lots of sanding, grain filling, and spraying to be done.

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Last edited by louhaskell on May Fri 05, 2017 1:40 pm, edited 1 time in total.

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Fri 05, 2017 12:57 pm 
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BTW, Lou, I really like that picture of your house at the top of your home page! Nice place!

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If talk is cheap, it's because the supply usually exceeds the demand.


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Fri 05, 2017 1:32 pm 
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Well, Chuck, I am sure that comment was a bit tongue-in-cheek since I live in Ohio. That photo was taken at Bandon Beach , Oregon, several years ago. It is not my house, but I sure wish it was. The Oregon coast is a place for great views. Love to go there.

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Fri 05, 2017 3:49 pm 
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It was, but I was too afraid it might actually be your house so I didn't add a smiley face just in case.

I did get caught up in reading about WLW - fascinating! And I plan to return and explore some more of those pages as time permits.

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If talk is cheap, it's because the supply usually exceeds the demand.


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Wed 24, 2017 8:49 pm 
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Finally....
I got my latest batch of boards from China, exactly 3 weeks plus 1 day after I ordered them, same as last time. I had ordered more parts to make another board so this morning was soldering time. I populated all components and this time, everything fit just as I had recalculated. That micrometer I bought sure did the trick on measuring some of the components. Got it all done, loaded the software, and boom...it worked!
You can see the real final photo of the board below.

There are next steps now:
1. I got 6 boards in this last batch (got 5 last time.. so who knows why). I have 1 board promised I know of but will check back through this thread. I seem to recall someone requested a board. They get first call if I find that. If you want a board, PM me. I am charging $5 plus shipping. I have the original board too which can sort of be used but would require some rework as I discussed. Those are free if someone wants them.
2. I need to package the software all up to give to others. I will make a download file that can be setup in your Arduino directory so you can generate the software and download to the Arduino Nano on the board. I expect there will be updates in the future so it will be best to have a development environment to generate and download future updates. I can also make available the Gerber file that is used to make boards. If someone wants their own batch of boards, all that is needed is the Gerber file. You order and it gets delivered to you. I got 6 boards for $27 which included shipping.
3. I will also writeup a small user manual
4. I still need to get with my friend and build the case for this with his laser cutter. I may make those available if it is easy to crank them out. I expect to be using clear acrylic so the display can be seen through the case. I am guessing those may be about $15-$20. More info in the near future.
5. There will be future software updates I am sure as I use this thing. The software now takes up 75% of program memory and 40% of data memory so more things can be added.
6. I do not plan to build these for folks. I am sharing this to give back to those on the forum who have helped me so much over the past 5 years. This design and software are open source; I do not plan to make money on this (and I hope to not see anyone else make money either on it). I will have appropriate copyrights and software licenses in place for that.
7. I do not plan custom versions at this time. I can think of other possibilities but, if you are looking for that, have at it. Doing this yourself is part of the fun.

Image

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Wed 24, 2017 8:56 pm 
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Good job Lou! Now it's time for me to start collecting the parts. I did get a Nano cheap, from Tayda Electronics, so hopefully it will be suitable. Now I just need everything else!

Colin


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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Thu 25, 2017 3:31 am 
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Before anyone starts ordering parts, there is a need to update the parts list based on changes. Two items have changed - the rotary encoder and power plug. The rotary encoder now has a shaft as long as the pots so that they can all extend out the top of the case. The power plug has the tabs as needed and is available whereas the other one is now backordered I believe.
Here is a link to the new list: http://louhaskell.com/data/generator/generatorBOM.pdf

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Sat 27, 2017 7:59 pm 
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Yesterday and today, I shipped 4 boards out to folks. That means I have only 1 left. Holler if you want it. The shipping comes in at about $3 so, I have charged $8 for each board.
For those now building the board, here is the first set of instructions.
First of all, you will need to modify ONE and only ONE of the 9850 DDS generator boards, which is used for DDS2 in the schematic.
Here is a link to the article that shows how to modify so that the signal can be AM modulated.
http://www.nomad.ee/micros/rfgenerator/

As you get parts to put on the board , all of the parts are marked by number, except for C15 which is the 1uF capacitor at the top of DDS1. I marked that for you in the photo of the board below. Also note the position of parts that must go in with the proper orientation. I placed red arrows to ICs and regulator chips so you can see the pin1 dot on the IC and the regulator tab position. Also, the electrolytic caps have the "+" sign on the board by their symbol. You can also see the grey stripe in the photo which is on the side of the electrolytic where the negative terminal is placed. Note the orientation of the Arduino board and the DDS boards, The modified board is DDS2 shown on the right side.
Refer to the board photo (large size so you can enlarge to see clearly) -> http://louhaskell.com/data/generator/generator-board-parts-placement.jpg
For the LCD, I have mounted mine on spacers so it is raised up to more easily be seen through a clear front cover. I used a 8 pin header for this. Note that 9 pins are used on the display but, although there is a connection on the PCB for it, the operation does not need it (signal is called MISO). So the LCD display has a pin sticking out the end that is not connected and just looks wrong! But it is OK.
Image

I also have the schematic in PDF format so you can blow it up to more easily read it.
See -> http://louhaskell.com/data/generator/generator-schematic-v1.7.pdf

I am now working on writing the user guide and also setting up the software for you. I will publish the source code and also a precompiled hex format file that you can easily download to the Arduino without needing the full Arduino development environment. This special loader works only on Windows, so I have to test that on my Windows machine. Look for that ...soon.

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 Post subject: Re: Microcontroller Based Signal Generator
PostPosted: May Sun 28, 2017 2:20 pm 
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And now for the software....

Dusted off my laptop (it's Windows which I hate so I do not use it much..;-) and downloaded the Arduino development environment.
I built a zip file containing all of the software and put it on the website I use for this project. Inside this zip file is a README file explaining how to compile and upload the code to the Nano. I tried to make it as easy as possible. If you are not familiar with the Arduino tools, there are good tutorials on the website.
You should be able to learn the whole thing and get the code on the Nano in under 30 minutes.

There is another tool you can use to get the code onto the Nano which does not require the Arduino tools. I have provided a pre-compiled file of the full code in the zip file (that ends in '.hex'). Using a tool called xloader, you can simply run that using the settings requested and upload the code.
Instructions for that are in the README file. The loader tool is a home brew project itself and can be a bit flaky, so be warned. Specifically, you have to know the correct port for the Nano or it will hang saying '..uploading' forever requiring you to go into Windows to kill the program. Not good coding technique.
I do recommend that you get the Arduino toolset to be able to look at the code and to easily get any updates plus customize the code as you wish.
I tried to use good coding techniques throughout such as specifying all settings in define statements up front.

Here is a link to the zip file -> http://louhaskell.com/data/generator/Sweep-generator-ReleaseV1.0.zip

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