Contents

ESP32 PCB

Several different revisions of our PCB are in use by now.
Here you can find information about the following revisions: 1.2, 1.3, 1.5. and 1.6
For each revision, the respective section contains information about known bugs, pin layout, features, and more.

Revision 1.6

PCB

KiCAD and Gerber files are available in our hardware repository: Minimal Rev 1.6

Bugs

Currently, there are no known bugs.

Connections on the ESP32 PCB Rev 1.6

Header Pin Software Pin PCB Connection
HT_RL PIN 2 OUT SSR Heating
T_SENS PIN 16 SIG Temperature sensor
I2C PIN 21 SDA Display and pressure sensor - Pin SDA
I2C PIN 22 SCL Display and pressure sensor - Pin SCL
V_IN - 5V Switching power supply (5 Volt)
PV_RL PIN 17 Valve Relay 3-way-valve
PV_RL PIN 27 Pump Relay pump
BPSW_SW PIN 34 BREW Brew switch or optocoupler
BPSW_SW PIN 39 PWR Power switch
BPSW_SW PIN 35 STEAM Steam switch
BPSW_SW PIN 36 WATER Hot water switch (not yet implemented)
S_LED PIN 26 OUT Status or Temp LED
W_SENS PIN 23 SIG Water level sensor
SCALE PIN 25 DAT2 Scale DAT2
SCALE PIN 32 DAT Scale DAT
SCALE PIN 33 CLK Scale CLK
GPIO PIN 1 IO01 Reserved for later use, e.g. Brew switch LED
GPIO PIN 3 IO03 Reserved for later use, e.g. Rotary encoder CLK
GPIO PIN 4 IO04 Reserved for later use, e.g. Rotary encoder DT
GPIO PIN 5 IO05 Reserved for later use, e.g. Rotary encoder SW
GPIO PIN 21 SDA Reserved for later use, e.g. IO Expander
GPIO PIN 22 SCL Reserved for later use, e.g. IO Expander
GPIO PIN 12 IO12 JTAG Debugger TDI
GPIO PIN 13 IO13 JTAG Debugger TCK
GPIO PIN 14 IO14 JTAG Debugger TMS
GPIO PIN 15 IO15 JTAG Debugger TDO
GPIO PIN 18 IO18 Reserved for later use, e.g. Dimmer ZC
GPIO PIN 19 IO19 Reserved for later use, e.g. Steam switch LED

Placement and Function

All required parts and their function are listed here:

Inscription PCB Part Function
C1 Electrical capacitor 220 µF Stabilization of power supply
C2 Ceramic capacitor 100 nF Stabilization of power supply
R1 Resistor 220 Ω Resistor Status LED
R2 Resistor 47 kΩ Pull down/up steam switch
R3 Resistor 47 kΩ Pull down/up power switch
R4 Resistor 4,7 kΩ Pull up i2C
R5 Resistor 4,7 kΩ Pull up i2C
R6 Resistor 47 kΩ Pull down/up brew switch or optocoupler
R7 Resistor 47 kΩ Pull down/up hot water switch
JP1 Solder jumper Resistor bypass for LED when using WS1812 LED
JP2 Jumper Pull down or Pull up for hot water switch
JP3 Jumper Pull down or Pull up for brew switch or optocoupler
JP4 Jumper Pull down or Pull up for power switch
JP5 Jumper Pull down or Pull up for steam switch

Jumper Settings

The jumpers allow switching the resistors between pulldown and pullup for the hot water, brewing, power, and steam switches. These resistors define the state of the switch input when it is not activated. The standard configuration has all jumpers set to pulldown.

Changes

  • Rounded corners for the PCB
  • Pull resistors for brewing, hot water, steam, and power are pluggable
  • Adjusted position and size of the installation space for Elko and Kerko

Revision 1.5

PCB

KiCAD and Gerber files are available in our hardware repository: Minimal Rev 1.5

Bugs

Currently, there are no known bugs.

Connections on the ESP32 PCB Rev 1.5

Header Pin Software Pin PCB Connection
HT_RL PIN 2 OUT SSR Heating
T_SENS PIN 16 SIG Temperature sensor
I2C PIN 21 SDA Display and pressure sensor - Pin SDA
I2C PIN 22 SCL Display and pressure sensor - Pin SCL
V_IN - 5V Switching power supply (5 Volt)
PV_RL PIN 17 Valve Relay 3-way-valve
PV_RL PIN 27 Pump Relay pump
BPSW_SW PIN 34 BREW Brew switch or optocoupler
BPSW_SW PIN 39 PWR Power switch
BPSW_SW PIN 35 STEAM Steam switch
BPSW_SW PIN 36 WATER Hot water switch (not yet implemented)
S_LED PIN 26 OUT Status LED
W_SENS PIN 23 SIG Water level sensor
SCALE PIN 25 DAT2 Scale DAT2
SCALE PIN 32 DAT Scale DAT
SCALE PIN 33 CLK Scale CLK
GPIO PIN 1 IO01 Reserved for later use, e.g. Brew switch LED
GPIO PIN 3 IO03 Reserved for later use, e.g. Rotary encoder CLK
GPIO PIN 4 IO04 Reserved for later use, e.g. Rotary encoder DT
GPIO PIN 5 IO05 Reserved for later use, e.g. Rotary encoder SW
GPIO PIN 21 SDA Reserved for later use, e.g. IO Expander
GPIO PIN 22 SCL Reserved for later use, e.g. IO Expander
GPIO PIN 12 IO12 JTAG Debugger TDI
GPIO PIN 13 IO13 JTAG Debugger TCK
GPIO PIN 14 IO14 JTAG Debugger TMS
GPIO PIN 15 IO15 JTAG Debugger TDO
GPIO PIN 18 IO18 Reserved for later use, e.g. Dimmer ZC
GPIO PIN 19 IO19 Reserved for later use, e.g. Steam switch LED

Placement and Function

All required parts and their function are listed here:

Inscription PCB Part Function
C1 Electrical capacitor 220 µF Stabilization of power supply
C2 Ceramic capacitor 100 nF Stabilization of power supply
R1 Resistor 220 Ω Resistor Status LED
R2 Resistor 47 kΩ Pull down steam switch
R3 Resistor 47 kΩ Pull down power switch
R4 Resistor 4,7 kΩ Pull up i2C
R5 Resistor 4,7 kΩ Pull up i2C
R6 Resistor 47 kΩ Pull down/up brew switch or optocoupler
R7 Resistor 47 kΩ Pull down hot water switch
JP1 Solder jumper Resistor bypass for LED when using WS1812 LED
JP2 Solder jumper Pull down or Pull up for brew switch or optocoupler

Revision 1.3

PCB

KiCAD and Gerber files are available in our hardware repository: Minimal Rev 1.3

Bugs

Faulty optocoupler for brew detection:

  • Only compatible with high level trigger optocoupler
  • Workaround for low level trigger: Don’t solder pulldown resistor R3, and depending on software version, set the following:
    • MASTER -> OPTOCOUPLER_TYPE to LOW
    • 3.3.0 and older -> PINMODEVOLTAGESENSOR to INPUT_PULLUP and VOLTAGESENSOR to LOW
  • Missing GPIO: IO03, IO04, IO05

Connections on the ESP32 PCB Rev 1.3

Header Pin Software Pin PCB Connection
HT_RL PIN 2 IO02 SSR Heating
T_SENS PIN 16 IO16 Temperature sensor
I2C PIN 21 SDA Display and pressure sensor - PIN SDA
I2C PIN 22 SDL Display and pressure sensor - PIN SCL
V_IN - V_IN Switching power supply (5 Volt)
PV_RL PIN 17 Valve Relay 3-way-valve
PV_RL PIN 27 Pump Relay pump
B_SW PIN 34 IO34 Brew switch or optocoupler
S_SW PIN 35 IO35 Steam switch
P_SW PIN 39 IO39 Power switch
E_TRIG PIN 25 IO25 Trigger Silvia E CPU Up to s/w version 3.X, afterwards SCALE DAT2
S_LED PIN 26 IO26 Status LED
W_SENS PIN 23 IO23 Water level sensor
SCALE PIN 32 DAT Scale DAT
SCALE PIN 33 CLK Scale CLK
GPIO PIN 1 IO01 Reserved for later use, e.g. Brew switch LED
GPIO PIN 12 IO12 JTAG Debugger TDI
GPIO PIN 13 IO13 JTAG Debugger TCK
GPIO PIN 14 IO14 JTAG Debugger TMS
GPIO PIN 15 IO15 JTAG Debugger TDO
GPIO PIN 18 IO18 Reserved for later use, e.g. Dimmer ZC
GPIO PIN 19 IO19 Reserved for later use, e.g. Steam switch LED
GPIO PIN 36 IO36 Hot water switch (not yet implemented)

Placement and Function

All required parts and their function are listed here:

Inscription PCB Part Function
C1 Electrical capacitor 220 µF Stabilization of power supply
C2 Ceramic capacitor 100 nF Stabilization of power supply
R1 Resistor 4,7 kΩ Pull up i2C
R2 Resistor 4,7 kΩ Pull up i2C
R3 Resistor 47 kΩ Pull down brew switch
R4 Resistor 47 kΩ Pull down power switch
R5 Resistor 47 kΩ Pull down steam switch
R6 Resistor 220 Ω Resistor Status LED
JP1 Solder jumper Resistor bypass for LED when using WS1812 LED

Revision 1.2

PCB

KiCAD and Gerber files are available in our hardware repository: Minimal Rev 1.2

Bugs

Errors in PCB inscription: HEADER | PCB Inscription | Correct Inscription

  • S_LED VCC 5V
    E_TRIG VCC 5V
    W_SENS IO36 IO23
    GPIO IO23 IO36

Faulty optocoupler for brew detection:

  • Only compatible with high level trigger optocoupler
  • Workaround for low level trigger: Don’t solder pulldown resistor R3, and depending on software version, set the following:
    • MASTER -> OPTOCOUPLER_TYPE to LOW
    • 3.3.0 and older -> PINMODEVOLTAGESENSOR to INPUT_PULLUP and VOLTAGESENSOR to LOW
  • Missing GPIO: IO03, IO04, IO05

Connectors of the ESP32 PCB Rev 1.2

Header PIN Software PIN PCB Connection
HT_RL PIN 2 IO02 SSR Heating
T_SENS PIN 16 IO16 Temperature sensor
I2C PIN 21 SDA Display and pressure sensor - PIN SDA
I2C PIN 22 SDL Display and pressure sensor - PIN SCL
V_IN - V_IN Switching power supply (5 Volt)
PV_RL PIN 17 Valve Relay 3-way-valve
PV_RL PIN 27 Pump Relay pump
B_SW PIN 34 IO34 Brew switch or optocoupler
S_SW PIN 35 IO35 Steam switch
P_SW PIN 39 IO39 Power switch
E_TRIG PIN 25 IO25 Trigger Silvia E CPU Up to s/w version 3.X, afterwards SCALE DAT2
S_LED PIN 26 IO26 Status LED
W_SENS PIN 23 IO23 Water level sensor
SCALE PIN 32 DAT Scale DAT
SCALE PIN 33 CLK Scale CLK
GPIO PIN 1 IO01 Reserved for later use, e.g. Brew switch LED
GPIO PIN 12 IO12 JTAG Debugger TDI
GPIO PIN 13 IO13 JTAG Debugger TCK
GPIO PIN 14 IO14 JTAG Debugger TMS
GPIO PIN 15 IO15 JTAG Debugger TDO
GPIO PIN 18 IO18 Reserved for later use, e.g. Dimmer ZC
GPIO PIN 19 IO19 Reserved for later use, e.g. Steam switch LED
GPIO PIN 36 IO36 Hot water switch (not yet implemented)

Placement and Function

All required parts and their function are listed here:

Inscription PCB Part Function
C1 Electrical capacitor 220 µF Stabilization of power supply
C2 Ceramic capacitor 100 nF Stabilization of power supply
R1 Resistor 4,7 kΩ Pull up i2C
R2 Resistor 4,7 kΩ Pull up i2C
R3 Resistor 47 kΩ Pull down brew switch
R4 Resistor 47 kΩ Pull down power switch
R5 Resistor 47 kΩ Pull down steam switch
R6 Resistor 220 Ω Resistor Status LED
JP1 Solder jumper Resistor bypass for LED when using WS1812 LED