AVRSynth 32 (Part 7)

And here is my daughter with the finished AVRSynth 32. She is proud that she has helped to work on it. Now I'm going to explain to her how it works. Maybe she can tell the kids in school about it then. Well I talked in the last post about running it on 9 Volts, but I found out that this doesn't actually work. It gives a ticking noise on the clock of the midi input. This goes away when you apply 12 Volts. So there was a clear reason for this apparently. Well I'll see what next project I can do with my daughter again. I think some nice PCB, since that is what she likes not the wiring and stuff as I found out.

AVRSynth 32 (Part 6)

Today I started testing the AVRSynth 32. And unfortunately it did nothing :) So I started debugging. I started with checking if I had a signal on the midi input. And I did actually had a signal on the input of the opto coupler but nothing came out there. So I started to look at the schematics. I couldn't find anything wrong actually. After that I measured at the DIN connector on the back and saw that I also had signals on the other pins. Now I was confused. To be honest I actually never looked at what pins do what on a Midi connector :) So I started looking for a schematic.

And that is why I love the Internet so much. It took me about 5 seconds to come up with this. And guess what. I had the wrong pins. I never knew that a DIN connector is numbered in this way. Well you are not to old to learn ever I guess. After rewiring the connector I had a signal on the output of the opto coupler right away. So I hooked up audio to the unit and it gave a signal right away while playing on the midi keyboard. So it actually works :) After that I started to check all the functionality.

The first thing I noticed is that some switches worked the wrong way around. Here you see Oscillator A set to Square, well this looked like a Saw to me :) So I checked switch for switch. Strangly enough not all of them were wrong, but I'm pretty sure all the switches are mounted in the same orientation. Ah well. Who cares as long as it all works like it is supposed to. The only thing left to do now is hook up the power switch and attach the power to the power connector on the back panel. And I need to find a 12V adapter for it. I guess it will run on 9V as well btw.

And here is the end result. Looks neat doesn't it? I only need to clean the surface of the front panel. Some little speckles are on there. Well it sounds nice as well. It is a monophonic Virtual Analog synthesizer. As you can see with two Oscillators that can be switched between Square wave or Saw wave and only Oscillator B can be detuned. So oscillator A is always in tune. Makes it a neat tool to tune my modular I guess :) Tomorrow I'm going to show and demonstrate it to my daughter. And try to explain to her how it works. I hopes she likes it. I'm sure I'll do a last post about that.

AVRSynth 32 (Part 5)

Today I worked a bit on the AVRSynth 32 again. Unfortunately my daughter really lost interest in this project now. I explained to her what had to be done to wire the front panel components on the PCB and she couldn't really understand. Now is the documentation not very easy on this. So I can imagine she didn't get it. So I started this job on my own. Here you see a picture with all the wiring in place to interconnect the front panel components. Basically a 5 Volt and ground line on all the pots and 4 groups of switches that share a common bus line later on. So far so good.

Here you see a picture of the flat cable that runs to the PCB. This was a lot more complicated. 40 wires that you need to connect to the right place and only wire 1 is red and the red is gray :) I counted and recounted a lot of times to make sure that I had the right wire. Even even then I made a mistake. I cut a wire short that I had to extend later on. I also did some cross checks with the schematic so that I could check the right connection to the PCB. After these checks I was quite convinced it should be OK. Time to apply the power to do the famous Magic Smoke test.

And luckily no smoke :) Nothing got warm so I started to measure the power on the components. All looked well on there as well. I used a lab power supply with a very restricted current setting to be sure I couldn't short circuit anything. After this I removed the PCB again from the case. I remembered that I still had to solder an extra resistor on the bottom of the PCB. And I also still had the extra capacitor. I decided not to mount that one. I think it is only necessary with the other crystal option. But I'm not sure. I can always solder it in there. It won't break anything I'm sure. Well at least I have a working power led now :) Further more I only looked at some digital signals and it seems that the clock is running. I see activity on the data lines. Next thing is to attach some Midi and audio and do some testing.

AVRSynth 32 (Part 4)

Today I worked a bit more with my daughter on the AVRSynth 32. The next thing to do was to mount all the front panel components. As said before I had to drill the holes for the led holders a bit bigger. 8 mm turned out to be the right size. For the switches I puzzled a bit which ones to use. For the power I decided to go for a double switch so that I can switch both the power and the ground later on. The rest are single on of switches. The midi address selector switches are very close together so I had to leave the mounting ring of there. And because of that I decided to leave them of on the other ones as well.

Here you see a picture of the back of the front panel. I'm quite curious by the way about the material they used to make the front panel. It looks like PCB material but on the front it is black and white. If anyone has info on this stuff I'd like to hear more about it. The only thing I'm not sure about is the orientation of the switches. But I'll see about that when I start wiring and testing. The next thing to do on here is do the inter component wiring. But since my daughter already lost interest during the mounting of the components I wont do that now.

After this I did a little job on my own. Here you see how I'm applying pressure to get the header connector on the flat cable. I used a small bench vice for this since it is quite some pressure you need for this. I made a lot of cables in the past this way, but funny enough I couldn't remember anymore where pin 1 was supposed to go. So I looked up an good old IDE hard disk cable I made in the past to see how it was supposed to be mounted. Good that I save that kind of historic material ;) After this I also made two smaller 10 pin connectors on the left over flat cable.

And here is the end result of the cables and they are already in place on the PCB. The other end will be split up and going to the front panel components later on. I also found two left over components in the case. One resistor that I still have to mount on the bottom of the PCB. And a capacitor that should go on the X2 position (big crystal), but my kit came with a small crystal that is mounted in the X1 position. So now I'm not sure if I need to mount this capacitor or not. I'll have to find out somehow. Well I hope my daughter wants to work on it some more later on. I'd like to finish this project soon. I have enough other stuff laying around as well.

AVRSynth 32 (Part 3)

This afternoon I worked some more on the AVRSynth with my daughter. We actually managed to finish the PCB. It was not very exciting since only the connectors were left to solder. Strange thing is that for the small connectors there were two different kinds. One was a regular connector and the other one just a header connector. Ah well it works just the same and eventually it is inside the case so nobody will notice. After that the PCB needed to be mounted on the bottom of the casing. I drilled four holes in the bottom and used nuts and bolts to fasten everything.

After that we started mounting the panel components. First the ones on the rear. Not much there. Just an audio output connector on a jack, a connector for an external 12 Volts DC power supply and a midi jack. Strangly enough I also couldn't find the nuts and bolts that should have come with the midi jack I guess. But well I have enough of those. Then we continued with the front panel. I found the 8 potmeters as stated earlier in the bag with all the potmeters for the ASM-2. It looks like Elby just tossed everything together. Ah well now that I know it is OK.

We started to mount the potmeters. I found out quite quickly that I had to shorten them by sawing a piece of the shaft. Since there are metal it was not a very easy job. While it was doing this my daughter lost concentration and left. But we decided that I would finish this job. I also had a problem later on getting the knobs on. I had to find a special tool to fasten them. The screw is very tiny and is of the Hex/Allen/Imbus type. (I'm not sure what the correct English name is). I finally found one that barely fitted and was able to secure them. The next thing I found out is that the holes for the led holders are too small. So I will have to drill them larger I'm afraid. There is more DIY to this kit actually than I expected. But after this I stopped and will continue again when my daughter feels like it again.

AVRSynth 32 (Part 2)

After dinner today I went back to my modular desk for some more soldering. I asked my daughters if they wanted to join me in the studio since my wife had to go away and they were quite happy about it. Here you see a picture of me that my daughter took when I was soldering a whole bunch of diodes. And yes I'm wearing glasses. My eye sight is actually fine, but they have prism glasses that make it easier to focus. When I'm working long time my eyes don't get tires. And since there is not that much light down stairs my eyes have to work harder anyway. During soldering I tried to explain to my daughter also how a diode and a capacitor works. She says she understands it, but it is a bit difficult for me to believe. But I will try and keep explaining stuff to her. She seems to be very interested.

When we were busy my youngest daughter came to the studio as well. Dressed up as Minnie Mouse with the ears and all :) Isn't it sweet? Well now my oldest daughter is starting to explain to the youngest one what everything is on the PCB. I think that is so cool.
Well after that we continued to solder all the capacitors to the PCB. We could not find one of the capacitors but when I reread the documentation it turned out that this one needed to be soldered to the bottom of the PCB just like the resistor we couldn't find earlier.

Here is a picture of how far we got today. As I said before my daughter is quickly loosing concentration. So the PCB still is not finished. You can also see some drawings that I made while trying to explain what everything does. It is really fun for me to since my whole school period is passing by me :) And even though I used to hate it back then now I think it is fun. Life is weird right. I still haven't counted the potmeters on the ASM-2 by the way. So I still don't know if they are missing from the AVRSynth. Ah well I can't do everything at the same time. I'm doing a lot already I think.

After soldering the girls wanted to jam a bit on some synthesizers. Here you see them play on my Korg M3. Today they discovered Karma and how much fun that is. It didn't sound very harmonious, but it was nice that they played without fighting over it. That is harmonious as well right? :) They were quite lucky too because with all this fun I forgot the time and they were in bed half an hour later than usual. I have seen a lot of trick to stall before then go to bed, but this one was even new for me ;)

AVRSynth 32 (Part 1)

Two days ago my oldest daughter had her 9th birthday. And since she is very interested in music, synthesizers and music I decided to give her a special gift. She got her first DIY Synthesizer project. It will become a AVRSynth 32 and it came as a complete kit from Elby Designs in Australia. She is very proud of it. We will build this one together and I will only work on it when she feels like it. But today we already started. First thing we did is see if all the components were present and it looked like some stuff like pot meters and switches are missing. But I also got the front panel components for the ASM-2 so maybe they got mixed up.

We started this nice father-daughter project today with the PCB. It is a digital synthesizer based on a ATMEGA32 8 bit microcontroller running on 16 Mhz. So actually it is a little computer. So the electronics are actually not that complex. We started by mounting the IC sockets and the resistors. Elby has everything nicely bagged and labeled by the way so you don't have to look long for a component of a certain value. My daughter looks up the components and the position it is supposed to go on the PCB and I do the soldering. She sees it like a big puzzle.

Here you can see how far we got today. All the resistors are in place now. She was already tired after this so we decided to stop. I guess we will continue this project soon. The nice thing is that she was very fascinated how the soldering works and I even managed to explain to her how a resistor works. I hope she keeps this enthusiastic about electronics, because I much rather do this kind of stuff with her than play with dolls ;) I'll update you soon on this project again. And now I'm going to count some ASM-2 front panel components.