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Eurorack LFO module

The LFO is built around Electric Druid's STOMPLFO and it can output 8 different waveforms, including 2 random waveforms(slope and levels). It can output these signals at frequencies between 0.05Hz and 25Hz, it has amplitude control, and offset control. It has a 3.5mm mono output and it needs a 5v supply.

Project Duration 1 weekend
Status Ongoing
Year 2026
01

Bill of Materials

Component Part Number Quantity Notes
Core IC STOMPLFO 1 0.05-25Hz, 8 waveforms
DIP 8 pin socket - 1 -
3.5mm mono socket(J1) PJ3001F 1 Any other mono 3.5mm female connector works
Perfboard - 1 -
DC barrel connector - 1 -
5V DC power supply - 1 -
1kΩ 5% 400mw resistor 594-SFR2500001001JR5 4 1%tolerance would be preffered and 1/4W is sufficient.
10K potentiometer PDB181-K420K-103C 4 B10K panel pount potentiometer
10kΩ 1% 1/4W RNMF14FAD10K0 1 -
100kΩ 1% 1/4W 10kΩ 1% 1/4W 1 -
100nF capacitor K104K15X7RF5WH5 7 10% tolerance, 50V, ceramic capacitors, code 104
10nF capacitor K103K15X7RF5TK2 2 10% tolerance, 50V, ceramic capacitors, code 103
02

Tools Used

Siglent SDS804X DSO
Digital Storage Oscilloscope for signal analysis and debugging and documenting.
Solder Station
WE1010 solder station"
03

Diagrams & Schematics

Circuit Diagram
Circuit Diagram showing passive filter on output and 4 CV inputs
04

Assembly Process

1

Preparation

Started placing passive components, followed by IC socket, cables, jack and lastly potentionmeters(everything was ordered by height) on the perfboard. Evrything was assembled according to the diagram above.

2

Soldering

Soldered each component in the ordered described prior.

3

Verified output signal and CV functionality

Results can be found in the pictures below.

4

Upcoming: Panel Assembly

Custom panel for Eurorack system will follow as an addition.

5

Upcoming: Power Supply Board

Custom power supply board for Eurorack system will follow as an addition.

05

Oscilloscope Analysis

sine
IMU SPI Communication
Clean 8 MHz SPI clock and data signals with proper setup/hold times. No signal integrity issues observed.
square
Motor Output PWM
D-shot 600 protocol waveform showing clean edges and proper timing. Ferrite bead filtering effective.
sweep
Power Rail Noise Analysis
5V rail noise measured at 15mV peak-to-peak during full throttle, well within acceptable limits.
triangle
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
saw
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
reverse saw
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
random levels
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
random slope
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
500ms random
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
1000ms random
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
saw min ampl
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
saw max ampl
Sensor Fusion Output
Madgwick filter output showing smooth attitude estimation with 1kHz update rate and minimal drift.
06

Resources & References

STOMPLFO Datasheet

Complete technical specifications and electrical characteristics for the STOMPLFO IC.

Electric Druid's article on the new gen of chips(including STOMPLFO)

Reference implementation of the Madgwick orientation filter for IMU sensor fusion.