Putting Atari Punk Console

In the comments to the topic with a comic about the basics of rations, someone noted that the best Hello World! for a beginner amateur radio is a multivibrator - a generator of rectangular oscillations .

That's right, but at first glance the multivibrator itself seems rather boring. However, in a company with a one-shot (yes, it all sounds pretty funny), it can be turned into the Atari Punk Console - the simplest electronic musical instrument, the scheme of which was first published in the 80s by the inventor Forrest Mims.

Having gained popularity due to its simplicity and overgrown with a huge number of modifications, the device is still an integral part of some subcultures and is often used by musicians writing in the 8-bit genre and around it. Addressing the corresponding Google request, you will see the issue of more than 2 million pages in length, including examples of manufacturing, synthesizers and sequencers based on APC, casings for it, etc.
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Under the cut is a modified schematic diagram, a list of components, recommendations for assembling at home. There is also a video with a demonstration, and a kit for assembling is available for the lazy.



The basis of the APC is the integrated chip 556 ( datasheet ), which upon closer inspection is nothing more than a pair of the most popular timers 555, produced from the 70s. This component has many analogues, including domestic production.

The tunable multivibrator (main tone generator) is implemented in the circuit on one such timer, and the one- shot , which is triggered by pulses coming from the tone generator, is implemented on the second one. The generator frequency is set by one variable resistor, and the width of the one-shot pulse is the second by the same resistor. There are some nuances in the principles of operation of this bundle. Their description is not the topic of this note, so I’m sending everyone interested in the story with illustrated examples.



In addition to the main components, the diagram shows the photoresistor R7 that responds to light and is switched on by a separate toggle switch, a LED for indication, and a pair of constant-value resistors connected directly to the transducers. This is done for the sake of shifting ranges, to eliminate the signal dips in the most borderline adjustment points. We also got rid of the speaker in favor of the usual audio jack to which you can connect headphones, or speakers with a built-in amplifier.

All components used are quite common. Problems can arise only with toggle switches and photoresistor. But as the first, any ON-ON switches with 3 contacts will be suitable (although in this case it will be necessary to fix the wiring for them).

Name	Name / denomination	Note
Ic1	Timer NE556N	DIP-14 body
POT1-2	500 kOhm variable resistor R1212N-A500K	Vertical output
POT3	Variable resistor 50 kOhm R1212N-A50K
S1-2	Switch SS-9 (ON-ON)	Total average contact
BT1	Button to SWT 80-7.0 board	Without fixing
R1, R4	1 kΩ resistor
R2	10 kΩ
R3	4.7 kΩ
R5	3 KOM
R6	24 kΩ
R7	Photoresistor VT93N1
C1	10 nF capacitor	Ceramic
C2	0.1 μF	Ceramic
C3	10 uF	Electrolytic
LED1	Light-emitting diode	Any
AUDIO	ST-111 stereo jack	For 3.5 mm jack
9V-BAT	Terminal BS-EC	Any terminal for "Krona"

By the way, the wiring and schematic diagram in Eagle CAD format can be downloaded on Narod.Disk. The layout of the board is different from what you see in the photo above because it is made in one layer. So even if you do not have the title of honorary Jedi of a laser iron, you should succeed. Unfortunately, I lost the latest version of the prototype and I can not attach his photos, but without attention to detail, you will get something like that .

I would like to remind you that when printing wiring from Eagle, you should first disable all unnecessary layers (leave only the bottom and pads / vias), and in the print settings set the daws solid, black (so that the printer prints a contrast image, and not textured porridge) and remember to remove daw mirror (we print the bottom layer of the board).

For those who are too lazy to tinker with ferric chloride, iron and the search for components, we, like last time, have a kit-radio designer for sale. The kit contains a lot of variegated components, soldering which you can get your first experience with a soldering iron.

In the near future I will try to tell you how to make a simple 8-step sequencer based on the Atari Punk Console and 4017 counter ( datasheet ). In the meantime, all successful experiments!