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hi Paul,

I was able to connect it to an amp and have some fun. Looks like the only thing I messed up is the direction on the A/B switch. I can fix that. I had the manual out and the quick start page. I was ready to test some specific items. I can't count the green blinks, or green and yellow, I can't do it. I also don't know if the items roll over or stop when they get to the min or max value. If it stops I should be able to click minus a bunch of times and know I'm at 0, then click + the number you want to select. If it wraps, or rolls over I don't know how to use it. I would much prefer a simple 7 segment display controlled by a shift register. I could wire up a shift register to a display, but I can't program these, so I guess I will keep trying. thanks

I'm such a nit wit, I never even thought to look for it on your website. Like duh...  :p

I got the code uploaded... It was, uh, easy. I now have a blue LED on the left and a green/red flashing led on the right. Yippy They are so bright! I need to swap out some resistors.

I used the version 2 of the code, not sure if it matters, and if it does, what it effects. I need to connect it to an amp and print the instructions, and have some fun. Thanks for again for your help!

I'm sorry to bother you, this should be easy. I put "easy uploader arduino hex" into google and it laughs at me. I can not find anything called easy uploader. I followed the instructions here, https://forum.arduino.cc/index.php?topic=410618.0

I was using admin command prompt, not power command, so I had to type it in perfectly, which I did, and it basically said windows does not recognize "C:\Arduino\hardware/tools/avr/bin/avrdude as a command. I do want to use the hex file because I am not a programmer at all.

I also don't know which of the two versions I should try. I used the only schematic I could find but now see there were two versions of the circuit board. I really appreciate your help.

Hi Paul, thanks so much!

Today I had set a side some time to test the little bugger. I was surprised about the hex file instead of a normal ino file. I expect it's due to some assembly language code inside the program. Unfortunately the guide I found online didn't work. It instructed me to turn on verbose when uploadig, looking at the actual command it uses and to replace the file locating of the hex file with your file. I used the command prompt, but there was an error, it could not fine a command at c: bla bla. Is there a better way? Thanks

I did the face plate over and adjusted the laser settings. I think I like the black better than faux aluminum. Next step is to install the program and start testing. I left off the components for the level shifting and will breadboard the amp first. After it's tested I will populate the board and solder them in. Do you have any input on the circuitry I asked about?

Hey there Paul,

I'm putting this together and everything is working out well. I am almost ready to test it. Thought I'd share some photos of it. I'm hoping to get some cool sounds from this little project. The panel is laser plastic and I noticed the text is too dark in the upper box. I will fix it. I'll make an aluminum panel for it once my workshop is warmer.

They arrived after all.

I got these 10 pcb's for $5 delivered, in 5 days. Not kidding. www.allpcb.com

I'm still waiting for all the parts to come in. Making progress. Yay!

I was hoping to show off my pc boards, but they are stuck in Chicago with the terrible roads due to the snow and cold.

Hi Paul,

Thanks for your help. I had already ordered my pc boards, I should have them in a few days. After I verify it works I would gladly share the files. I can provide the gerber files or the eagle files. Bear in mind I just tossed the board together and didn't start with a schematic first. Lesson learned.

I can add the pads for serial no problem, and any other mods needed. I may start over in eagle with a proper schematic. I did want to ask you. In an effort to make it a bit more eurorack standard, I wanted to convert the 0-5v audio to 5vpp. I made the board in a way that it can be wired in two ways. It's been a really long time since I studied op amp circuits. It can be wired to pass the dc to the 702 with 2.5vdc on the + input, or put in a capacitor in place of J1, jumper R2 and leave R1 out. Which method would you recommend?

PC boards are really cheap. I have time to work on it, and it looks like fun. Thanks

128k max jpg is hard to do. lol

forgot to mention, it's hp-20

I will share the files as well.

Hi Guys, I wanted to do an update to my project. A little background. I have been amazed by synths since I was 14. I was very poor and although I did make a few things back in the day, they were really basic. Fast forward from 1975 to now. I have the time and resources to finally make a cool synth. I wanted to start by making one of these and move on from there making a full modular synth myself. When I started working on the pcb I was also researching where synths are nowadays. I learned about eurorack and decided that was the direction I would go. I know the miniAtmegatron isn't a true synthesizer module, but I wanted to get accustomed to making eurorack pcb's and faceplates anyway, so I decided to make the miniAtmegatron into a eurorack format. I have the pcb pretty much ready to order, and a pretty good idea what I want the faceplate to look like. The only modification I made was to remove the 22uF cap, and add in a TL702 in a level shifting amp. The schematic is a mess on paper, but it's basically powered by +/-12vdc + input goes to voltage divider providing 2.5vdc. signal enters through a 50k on - input and 100k feedback to - input. Then the 22uF cap added back to the output. Trying to convert 0-5 into +/-5. I will post a schematic soon.

On the aspect of getting more pots on there. Why not add an i2c a2d with 12-16 channels and be done with it. It would have to make coding simpler.

Um can't find a way to tell this thing to upload the images...

Thank you so much. You're the best!

Hello,

I want to make my own miniatmegatron like device. Is it open source, and or, would you be willing to help at all? I think I have it mostly, but I need to know if the pots increase voltage with clockwise, or counterclockwise rotation. Thanks!