random things I made and things I learnt making them
Previous Post Block diagram - System Overview The step sequencer will be interface with the Novation BassStation via the ribbon cable on the left, with optional support for 3rd devices via a MIDI interface on the right. This will allow the sequencer to be reused for other MIDI-supported devices. Microcontroller pinout The microcontroller pinout specifics…
Previous Post Front panel design So lets talks about how we want the front panel to be laid out. Lets start with the connector interface: 20-Pin Ribbon cable connector for the synth interface switching. Power (in the form of a barrel connector). MIDI in/out (for future compatibility with 3rd party devices). Convention says we put…
Previous Post Power Supply Requirements Description Total 1 MCU (STM32G0B1) 3.3V 10mA, at max settings 10mA 2 BassStation I/O 5V 8uA; each ch, drawn from bass station connector 8uA 3 RGB LED Driver IC (TLC5955) 5V 2 x 1.5A (500mA per colour group) 3A 4 Keyscan IC (ADP5587) 3.3V 200uA per key pressed 50uA per…
Designing the sequencer Previous Post So whats next? Well we need some way to set the steps on the sequencer. I want 16 steps per bar, each step can be illumintated by the user, with an ability to set the note (and the duration). The sequencer runs through the individual steps at a given tempo,…
Recap Previous post Previously I made the plan to design a sequencer for the original Novation BassStation. This would work by switching the connections on the ribbon cable that connected the keyboard to the motherboard. I mapped out the signal on the ribbon cable, now I needed to decide how to multiplex these signals electronically.…
Intro I just scored this original Novation BassStation synth on Ebay. It's a hybrid synth that uses digital timing control courtesy of an MCU (Panasonic MN1883217) to control two analog oscilators. Legend tells that it has a richer sound than the rack mounted version. Well, i'm not qualified to verify such claims, but it is…
Designing the hardware This project repurposes the power supply units (PSU) found in datacentre servers. The PSU are very powerful (12V @ 600W), efficient and compact. They are useful for charging LIPO batteries (with some modification) and running brushless motors or any circuit that draws large amounts of current. These PSU are replaced in industry…
Hardware Design Brief The purpose of this project is to design, build a programmable guitar FX pedal using a Cortex-M4F micro and I2S. This will provide a platform for development and experimentation of DSP algorithms and techniques. This is also an experiment to use C++ in embedded development. Evaluating the 24bit ADC and DAC Digilent…
System Overview Project details for the hardware can be found here Required Kicad Hardware library: https://github.com/cracked-machine/KicadLibrary For details of the MCU configuration and firmware refer to FunctionGeneratorCortexM4_SW Note, RevB was the final design. RevC was not built and is an untested future proposal. Features This STM32-based instrument has the following features: Output signal with synchronized…
DSP Peak Detector Algorithm Note, X is the channel number. MIXER_PEAK_MAPPING and SPLITTER_PEAK_MAPPING are used to support GPIO mappings for different PCB layouts. ADC input demux The data from multiple ADC channels is interlaced into a single array: [0]=CH1, [1]=CH2, [2]=CH3, [3]=CH4, [5]=CH1... This must be demuxed or binned according to ADC_NUMBER_OF_CHANS Average sampled voltage…
Overview Each of these designs use a TC4667 charge pump to create a negative voltage from a +9VDC supply. DC offset adjustment of the AC output signal is attained via the +/- voltage divider OFFSET potentiometer. This is summed along with the generated waveform. The amplitude of the output waveform is determined by the feedback…
The Experiment Here is a common dual opamp configuration: U1A is an attenuator configuration while U1B is a positive gain configuration. Here R3 is just a resistor to ground, but in practice R3 might represent a sub-circuit consisting of an active filter. What is the relationship between the two opamps regarding their gain and distortion…
Here's is a quick visual guide to illustrate how the trigger and threshold pins can affect the output of this timer IC chip. Trigger active Here the signal sent to the trigger is less than 1/3 of the supply voltage (VCC). The output is 1. The discharge transistor is disabled. Threshold active Here the signal…
In a word, impedance. The source impedance from your instrument/amplifier signal, coupled with the capacitance of the cable, creates a low pass filter. The makeup of a standard shielded, unbalanced cable matches that of a capacitor Any signal at a frequency above the cutoff will be attenuated by 1/3 relative to the input signal voltage…
Ever needed a negative voltage rail to quickly test something on the bread board? Look no further. - Abstract: This design uses the "classic" MC34063 switching regulator IC to invert the input voltage rail to a negative voltage, simultaneously stepping up/down the output depending on the position of the rotary dip switch. The resistors in…
Inductance is the relationship between the current and the magnetic field generated in a coil. Each is proportional to the delta of the other. L = l + 0.45 d d 2 n 2 d is diameter of coil in meters, n is number of coil turns, l is length of coil in meters…