Help on the "Master of Synthesis" module

I have to admit that I am not sure I have a name for this project which is why I just named it Master or Synthesis. Basically its a controller capable of an entire living room lined with modular synth cabinets. I had it in the plan to build a computer as close from scratch as possible. I have thought about Raspberry Pi in the past, but I have not found code that would work adequately for what I had planned. I decided on an embedded systems project (micro-controllers). I want to make this project accessible to anyone who wants to build it. However, I do hope to write a series of DIY books on the polished version of this project “Master of Synthesis”.

.

I will give more details as we go along. Right now I am needing help understand how a control voltage is produced. I am aware of the implications of how difficult this project will be. I have been working on it on and off for a couple years now. After losing heart in a college I decided on a taking this project seriously.

.

.

How do you convert digital to analogue properly?

I am having trouble understand how a control voltage is created from a digital 1s and 0s. From what I could manage to find, a control voltage is produced from a system of operational amplifiers. However, I am hopeful some one on this website could point me in the right direction as to what is involved in designing this type of circuit. I appreciate any help you guys have time for.

This is far beyond what can be reasonably covered on a message board but, to your question in purple, I’d begin by studying how ones and zeros can be used to represent other symbols like numbers and letters. For example, the upper case letter A can be expressed in one byte using the [ASCII encoding standard, hexidecimal 41. Converting hex 41 to binary gives the following eight bits:

0100 0001

If you were to build a controller that would play the musical note of A when it received 0100 0001 (perhaps generated by a bank of eight toggle switches) and the musical note of B when it received 0100 0010 (ASCII B is hex 42), you’d have a two note keyboard. Continue to code the additional notes of the musical octave an you have something approaching a playable instrument.

Of course, this relies on the source of the incoming data and the controller having previously ‘agreed’ on how to interpret these bits. For digital/analog conversion to be meaningful, there must be some rules and terms combined into a unified standard for how these ones and zeros are used. For audio and other media, there are tons of different standards that have been used over the years, for example WAV files vs MP3s.

As an analogy, consider how we read music. We see how the notes are arranged on the staff and our ‘controller’ (the human brain) converts to finger positions on the keyboard, trumpet valves or viola strings. If we didn’t all agree to the standardization of how to interpret the notes on the page, we aren’t going to sound very good.](ASCII - Wikipedia)

Of course, this relies on the source of the incoming data and the controller having previously ‘agreed’ on how to interpret these bits. For digital/analog conversion to be meaningful, there must be some rules and terms combined into a unified standard for how these ones and zeros are used.

.

.

I found more information on a term I came across. I did not know the meaning of this term when I first read it. The acronym DAC is basically a shorter term for D/A converter or digital to analogue. After searching that with the words tutorial I was able to find formulas that I could use. I am still looking at different applications, but at least now I have a way to “interpret bits” like you said.

.

I plan on starting with a resister ladder and then experimenting with resister values until I have an ideal power consumption. I am also thinking about using an operational amplifier to make it more power efficient. I was going to do some experiments on the bench today, but my instructor for electrical trades gave us book work to do. I plan on experimenting with with different theories and formulas this week end.

.

I will be sure to make a complete schematic, the math used, and the final test run I plan on doing with an ardunio. I have managed to figure out how to make a very simplified VCO from transistors. It still needs a proper temperature compensation component added to the design, but for it works great for the experiments I done and plan to do.

Update:

.

I managed to clean up my electronics lab area and pick up my apartment. However, I have a test on Mike Holts NEC tomorrow and Wednesday. So, I only took a moment to do a very simple experimenting with a resister ladder. My apartment was a train wreck last Friday. It seems to work beautifully. GreatScott on YT did a wonderful tutorial on DACs and I plan on experimenting with this further only with D-type registers and possibly a S-ram chip with an arduino. With any luck I will be able to tweak it enough to use an LM 324 to drive the transistor VCO that I have been designing.

.

I will be doing this next week end. Hopefully nothing major will need to be done for my Electrical trades class for the Monday fallowing.