ER-STIX

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ER-STIX P1080921 720PX.jpg

Features

  • Similar to Mutable Instruments Branches
    • Dual Bernoulli Gate
  • Differences vs Branches
    • Only has 1 GATE input
    • No push buttons
    • 0-5V input/outputs
  • Built on ER-PROTO-02
  • Arduino Pro Mini
  • Protection on all external jacks with Schottky diode clamps
  • 10-pin Eurorack power
    • Uses +12V only

Operation

  • Receives single Gate on J1
  • RV1 controls OUT 1
  • RV2 controls OUT 2
  • RV3 is mode for OUT 1
  • RV4 is mode for OUT 2

Arduino Pro Mini

  • Works with ATMega168 (or 328)
  • Program from FTDI

ArdruinoProMini-EBAY PART-720px.png

Arduino Pins

ER-STIX-Arduino.PNG

Controls

  • RV1 - Probabilistic ratio for Output 1
    • Center = 50-50, CCW = Out1A on 100%, CW = 0% on OUT1B
    • Inserting J3 jack disables RV1
  • RV2 - Probabilistic ratio for Output 2
    • Center = 50-50, CCW = Out1A on 100%, CW = 0% on OUT1B
    • Inserting J3 jack disables RV1
  • RV3 - OUT 1 Mode
    • 7-12 o'clock = Normal Mode drives only OUT1A or OUT1B
    • 12-5 o'clock = Drives both OUT1A and OUT1B
  • RV4 - OUT 2 Mode
    • 7-12 o'clock = Normal Mode drives only OU21A or OUT2B
    • 12-5 o'clock = Drives both OUT2A and OUT2B

Jacks

J1 - Gate

  • 0.6V threshold GATE input

J2 - Random %

  • 0-5V control input
  • Inserting jack disables RV1
  • 0V = 100% on OUT1A, 2.5V = 50% on OUT1A/OUT1B, 5V = 100% on OUT1B

J3 - Out1A

  • Gate output 1
  • 0-5V digital output

J4 - Out1B

  • Gate output 1
  • 0-5V digital output

J5 - Out2A

  • Gate output 2
  • 0-5V digital output

J6 - Out2B

  • Gate output 2
  • 0-5V digital output

Schematics

Software

  • Arduino IDE
  • Pot/GATEs Test
    • Used for testing the hardware works
    • Reads (4) pots and prints values to monitor, write values to serial
    • Toggles GATE outs - one at a time
    • Tests RV1/J2 loopback
  • Simplest Version 1
    • 2 pots, one for OUT1A/B, other for OUT2A/2B
  • Still pretty simple - Version 2
    • Adds (2) mode control knobs
    • 7 o-clock = 12 o'clock = Normal mode
    • 12 o-clock - 5 o=clock = Send Outputs on both OUTxA and OUTxB
Sketch uses 1990 bytes (13%) of program storage space. Maximum is 14336 bytes.
Global variables use 13 bytes (1%) of dynamic memory, leaving 1011 bytes for local variables. Maximum is 1024 bytes.

Parts List

ER-PROTO-02-DB REAR PWR.png

Find Qty Ref Des Part Number
1 1 R35 1K
2 1 C1 10uF
3 5 D1-D5 BAT41
4 1 J9 Conn, IDC, Box, 2x5
5 2 LED1, LED2 LED_Dual_2pin
6 1 Q1 2N3904
7 1 R1 10
8 1 U1 ARDUINO PRO MINI
11 6 RX2, RX7, RX9, RX15, RX17 1K
12 2 RVX1, RVX2 100K
13 2 RX3, RX4 220
14 2 RX11, RX13 100K
7 6 JX1-JX6 Jack