Atari Synth Box

Greetings everyone, and welcome back.

Here's something loud and exciting: the Atari Synth Box. The Atari Synth Box is a sound generator that uses two potentiometers to modulate and generate sound using two 555-timer ICs.

Atari Punk Consoles (APCs) are a type of DIY sound synthesizer that use the 555 timer IC (integrated circuit) to produce square wave sounds reminiscent of early video game music. The name "Atari Punk Console" was coined by Forrest Mims III, who originally published the design as a "Stepped Tone Generator." The sound produced is similar to the chiptunes from Atari games, hence the name.

Here, we have used two 555-timer ICs coupled in both astable and monostable multivibrator modes. This means that one timer IC is operating in free mode and generating a square wave signal. As a result, the tone is continuous. The first 555 timer IC generates an external signal that triggers the second 555 timer, which generates a single output pulse. We can change these rhythmic patterns with the potentiometers.

We created our own Atari Punk Console, which is incredibly small and utilizes all SMD components, borrowing influence from the original. A 3D printed enclosure was created to hold all the electronics in a compact yet organized form.

Our version needs an external speaker in order to deliver sound, and it requires a 12V input and a 3.5mm audio jack output.

This Instructables is about the whole build process of this small project, so let's get started with the build.

These were the materials required for this project.

• Custom PCB (Provided by HQ NextPCB)
• Timer IC: NE555 SOIC8 Package
• 100K Potentiometers
• Toggle Switch
• 1K 0805 Resistor
• 470 Ohms 1206 Resistor
• 100nF 1206 Capacitor
• SMD 3.5mm Audio Jack
• Barrel DC Jack
• 12V Power Source
• 3.5mm Audio Input Speaker system

We first included a model of potentiometer and a knob switch in Fusion360, as these two components would be the center of our design.

We used two potentiometers and positioned them side by side, with a toggle switch in between. These parts formed the basis of the enclosure design, and the circuit was installed inside the housing.

The enclosure was divided into two sections: the lid portion and the main body, which houses all of the electronics. We also included a third element, which was an Atari logo that was positioned on top of the main body of the enclosure.

To print the enclosure main body, we use Grey PLA at 0.2mm layer height and 20% infill through a 0.6mm Nozzle.

We used white PLA to print the lid portion with identical settings, and two colors of filament were used to create the logo.

After completing the model, we started the PCB design process, which started with creating the schematic.

Two 555 timer ICs are used in this project; the first timer is set up in astable mode. The middle lead of a 100k potentiometer has been added to the 555's discharge pin. The potentiometer is then connected to VCC via a 1k resistor, and the third pin is linked to the trigger and threshold pins.

The trigger pin of the second timer IC, which is set up in monostable mode, receives the output from the first 555 timer IC.

Here, we have added a second potentiometer that is wired between the second timer IC's discharge-threshold pin and VCC.

In order to connect the speaker, we have added a CON2 header pin. This pin is connected to the second timer IC's output via a 470 ohm resistor. Here, we can alter the speaker's volume by reducing the 470 ohm value.

In addition, a 10uF electrolytic capacitor has been added to the speaker output—not on the circuit—to serve as a filter.

By creating the outline and mounting holes by referring to the Cad design from the model, we designed the PCB and then sent it to HQ NextPCB for samples.

After completing the PCB design, we export the Gerber data and send it to HQ NextPCB for samples.

We placed an order for a Blue Soldermask LED board.

After placing the order, the PCBs were received within a week, and the PCB quality was pretty great.

HQ NextPCB and HQ Online are the overseas trading brands of Shenzhen Huaqiu Electronics Co., Ltd. Huaqiu has served national engineers for over 15 years, becoming a household name for providing full-feature multilayer PCBs engineers can trust.

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• First, we used a solder paste dispensing needle to apply solder paste (standard 37/63 Sn-Pb solder paste) to each component pad.
• Next, we pick and place each component onto their designated pad with the help of an ESD tweezer.
• The circuit is next placed on our PCB hotplate, which heats it from below up to the solder paste melting temperature. At this point, the components are connected to their pads as soon as the PCB achieves the solder paste melting temperature, in our case, 200 °C.

The circuit is now complete

• In order to attach the circuit in place, the first step in the body assembly is to add threaded inserts to the holes that have been created inside the body. In this case, we are utilizing M2.5 threaded inserts.
• Next, we insert the DC barrel jack on the body and tighten it using the included nut.
• The two potentiometers were then inserted into their designated locations and fastened with the included nut.
• In a similar manner, we inserted the toggle switch and used the included washer and nut to fasten it in place.
• The circuit is positioned over the mounting holes and fastened in place with two M2.5 bolts after the barrel jack, potentiometers, and switch have been mounted.
• To secure the audio jack in place, we placed a little bit of hot glue on the rib added within the body and then placed the audio jack board over it.

The basic assembly has been completed

This circuit already had everything labeled on it, which made wiring really easy. Using the CON3 and CON2 provided on the circuit with the label POT, we first connected the two potentiometers.

Next, we connected the DC jack's negative to the switch terminal. The switch's other terminal is connected to the circuit, which is likewise marked with a negative symbol.

The positive DC jack will be connected to the positive marked terminal of the circuit.

We are utilizing an SMD Audio Jack for the output, and the speaker output's negative and ground are linked.

Furthermore, a 10uF 25V capacitor was attached to the speaker output's positive terminal. The capacitor's negative terminal is linked to the audio jack's positive terminal.

Check the wiring diagram for a better depiction.

• We then installed a cover on the back side of the enclosure and fastened it to the main body using four M2 screws.
• To give it a final touch, we placed a tiny bit of super glue on the front side and positioned the Atari Nametag there. This will ensure that it remains permanently attached to the main body.

The assembly process is now complete.

Here's the result of this simple build: a functional synthesizer capable of generating many tunes, tones, and other altered sounds.

Now here's a critical question: If the Atari Synth Box we just built does not have a speaker, how are we going to output sound?

We will be connecting our synth box to an external speaker with an audio jack input so that we can play audio.

We are utilizing a setup for this work that is based on the ZK-1002M Bluetooth Amplifier module, which you can check out at the link below. We utilized this arrangement in a prior project.

https://www.instructables.com/Custom-Bluetooth-Speaker-With-ZK-1002M-Audio-Modul/

The following video demonstrates that the synth is functioning fairly well. It is obvious that the person using it is a novice, but someone with more musical experience might be able to create something really amazing with it.

With the exception of a centralized circuit that would contain all electronics on one tidy board and feature a speaker for output, this project was successful overall and does not require any further work.

If you are interested in this subject, have a look at a few of my synth projects.

https://www.instructables.com/Noise-Box/

https://www.instructables.com/Arduino-Atari-Synth/

Special thanks to HQ NextPCB for providing components that I've used in this project, check them out for getting all sorts of PCB or PCBA-related services for less cost.

Thanks for reaching this far, and I will be back with a new project soon.