Working on the Case

Today I worked on the case for the Outmoded Sequencer project. Originally I planed to use acrylic glass and laser cut it, but I did not found a service where I could cut a single piece cheap. So I am using wood, cut it to the right size using a Dremel tool, then sand it and spray painted it black. The color is a really deep black, which is not perfectly visible on the photos because of the black background.

You see a smaller panel with the two knobs and the speaker, which will be mounted on the top area of the larger base. If you look closely you can see the holes where the top panel will be fastened using the distant bolts.

I am using M2.5 threads with 2.8mm holes and distant bolts of 20mm length. Sadly there were no black distant bolts in this size, there were only M3 ones.

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Everything That Went Wrong

As expected, there were many things that went wrong in the process from the prototype to the first PCB version of the project. I would like to share them here, maybe it will prevent similar mistakes in one of your projects.

Wrong Values

Outmoded Sequencer Wrong Value

While drawing the circuit diagram, I copied all values from the components into this document. But later, I experimented with the prototype and changed components – but forgot to update the values in the circuit diagram.

When I soldered the components onto the PCB, I just read the values from the diagram and did not cross check them with the prototype. I soldered the wrong capacitor on the board and it took a while to find the problem. It was hard to remove the wrong component and replace it with the correct one.

How to fix later: If the shape of the components match, you can easily unsolder the wrong component and use the correct one. But often you have to destroy the wrong component to be able to unsolder it.

How to avoid: This is very easy to avoid and there are two safe strategies. First I keep a sheet with the printed circuit diagram beside the prototype. So I can easily note any changes I do and update the diagram later. Second, before I order a new PCB, I check all values in the diagram with the prototype.

Not Connected Copper Pour

Outmoded Sequencer Copper Pour

I created a copper pour on both sides of the PCB, but somehow I did not connect the pour on the bottom side with GND. This is not easily visible, because usually while drawing routes you keep your board free from the pours and just add them for the final touches.

How to fix later: You can not fix this entirely, but you can prevent the worst. Just scratch off the solder mask from the largest pours and connect them to ground with a small wire.

How to avoid: If you do the final checks, check each layer individually. So you will spot this problem immediately.

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Outmoded Sequencer Music Demo

For the demo video in my previous post, I did not really choose nice melodies. So I created a small composition using the outmoded sequencer:

For this music I connected the outmoded sequencer directly, after the potentiometer for the volume control, to an audio interface. Now I recorded the sound of the sequencer while I changed the matrix. After recording I added additional elements, like the percussion and bass lines.

Enjoy!

Outmoded Sequencer Project

I just started an interesting new project: The Outmoded Sequencer Project. It is an minimalistic music machine. You can use a 8×8 “programming” matrix to create simple melodies which are looping endlessly. This melody can be changed while the device is playing it. Here a short demonstration:

The device is divided into several parts as shown here:

Outmoded Sequencer Prototype Legend

My goals for the project were:

  • No microcontroller.
  • Only outmoded, basic and cheap components.
  • As minimalistic as possible.
  • Maximize the fun with these limitations.

Read all details how you can build this sequencer on the project page:

Have fun!

 

Boldport “The Cuttle” Arrived

Today the new project from Boldport Club arrived. It is called “The Cuttle” and it is a minimal configuration of the ATMega328-PU microcontroller with minimal elements to get it running.

As usual the PCB is artfully designed in shape of a cuttlefish. Soldering was easy this time.

Here some photos of the project how it arrived and at the end the final version with all components soldered into place.

I also made a short video where you see the ATMega in action:

The source code for the LED effect shown in the video is very simple:

void setup() {
  DDRD = 0xff;
  PORTD = 0x0f;
}
void loop() {
  const uint8_t first = ((PORTD & 0x80) != 0) ? 1 : 0;
  PORTD = ((PORTD << 1) | first);
  delay(50);
}

SMD Components Under the Microscope

Today I took some photos from common SMD components using a microscope. From naked eye, this components look so tiny and fascinating perfect. Looking at them using a microscope, they do not look that perfect anymore.

I cropped the pictures to make the picture better visible at lower resolutions. I always put a scale, which measures 1mm, on each photo. See each picture caption for a description of the component and more details.

New Application: Micro Disk

I published a new application to create “Micro Disk” images for embedded projects with very limited resources. This format fits perfectly on SD cards and it can be read with minimal effort.

The application is available as binary for macOS and Windows. The sources are available on GitHub which can be easily compiled for Linux.

The features of the Micro Disk format are:

  • File directory with ASCII file names.
  • Single file list which can store any number of files.
  • For each file, a name, the start block and the size in bytes is stored.
  • All files are stored in sequential blocks which makes reading simple and fast.
  • All files are aligned to the 512 byte blocks for a SD card.

Read more about the application, downloads and all details about the format.

Screenshots of the applications: