Free Electronic Circuit Design
H1, H2, H3, H4, H5, and H6 are the ports for control inputs. We can use these ports to read potentiometers, selector switches, buttons, or control voltage. Buttons connection to the control ports has been described in the previous section (I.4). See Figure 2 (part C and D) for the quick reference. Potentiometer can be connected directly to the control […]
Read moreMain foot switch (or main user button in non-pedal context) should be connected off-board through H13. The on-board button main user button KEY2 is provided for testing or maintenance. For additional buttons or foot switches, we can use any of control ports (H1,H2,..,H6) when available (not used for potentiometer or selector switch). We can also use encoder port (X2) to […]
Read moreLED1 is the main indicator, and LED2 is the auxiliary indicator. The main and auxiliary labelling is just for reference, as both LEDs have the same capability and we can program them independently. LED1 and LED2 are the on-board LEDs, and the panel- or enclosure-mounted indicator LEDs should be connected off-board through the header connector H16 and H17. For development […]
Read moreReset Button. KEY1 is the on-board reset button, is especially useful in development, testing, or reparation service. In a final product the on-board reset button should be inaccessible inside the enclosure, so any reset action (if needed) should be done by power cycling (unplugging and re-plugging the DC power input). Silent Boot. H15 is a header connector for silent boot […]
Read moreThe schematic diagram of the standard Blackstomp board is shown in the Figure 1. The circuit of the standard board is optimized (and compromised) between development and production usage. Bill of Materials ITEM COMPONENT REF QUANTITY 1 100k R2,R4 2 2 10k R1,R5,R6 3 3 330 R7,R13 2 4 1k R8,R11,R12,R3,R10 5 5 220 R14 1 6 47 R15,R16 2 […]
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The PDM (pulse-density modulation) has been widely used in the current technology of audio signal conversion (from analog to digital) because its simplicity while achieving high quality conversion. This technology is widely used in digital microphone, and it is basically a sigma delta modulator circuit which is used in many modern audio codec chip as well. It is an interesting […]
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Why ESP-IDF, C++, and Windows First of all, choosing the ESP-IDF frameworks is the best choice in terms of complete supports for all ESP32 peripherals’s functionality, because it’s the official framework released by the chip’s maker (Espressif). This choice is very important for long term projects, where “investing in time” is unavoidable to manage many things. Secondly, it might be […]
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Power supply is one of the main element in every electronic circuit, and the right AD/DC adapter circuit should be chosen if we want our device to accept power line voltage as the main supply. There several types of AC/DC adapter circuits, transformer-less (non-isolated), step-down transformer, and switched-mode power supply adapter. The schematic diagram of the circuits and how to […]
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Introduction Full-adder circuit is one of the main element of arithmetic logic unit. It is the full-featured 1-bit (binary-digit) addition machine that can be assembled to construct a multi-bit adder machine. We can say it as a full-featured addition machine since it has “carry input” and a “carry-output”, in addition to the two 1-bit data inputs and one 1-bit data […]
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Since the release of ESP32 by Espressif, many application-specific modules based on this chip are produced. For example, Ai-Thinker produce image processing module with artificial intelligence support for image recognition. In the audio processing area, one interesting product by Ai-Thinker is the ESP32-A1S module. Because of the integrated AC101 codec inside, this module enable very compact and low cost solution […]
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Introduction to Reverberation Before getting into the design of DIY reverb pedal circuit, lets see the concept of reverberation first. Real reverberation happens in a performance chamber when the walls and every object inside reflects the sound back and forth. As the sound bounces back and forth in three dimensional space, the reflections creates more and more complex pattern. The […]
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