diff --git a/firmware/Makefile b/firmware/Makefile
index dd37fc4..86bbabd 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -146,6 +146,7 @@ CPPSRC = $(ALLCPPSRC) \
           uart.cpp \
           shared/crc.cpp \
           interpolation.cpp \
+          auxout.cpp \
           console/binary/tunerstudio_io_serial.cpp \
           console/binary/tunerstudio_io.cpp \
           main.cpp
diff --git a/firmware/auxout.cpp b/firmware/auxout.cpp
new file mode 100644
index 0000000..b94681f
--- /dev/null
+++ b/firmware/auxout.cpp
@@ -0,0 +1,65 @@
+#include "pwm.h"
+#include "lambda_conversion.h"
+
+#include "wideband_config.h"
+
+#include "hal.h"
+
+#ifdef AUXOUT_DAC_PWM_DEVICE
+
+// Rev2 low pass filter cut frequency is about 21Hz (sic!)
+// 48Mhz / (2 ^ 12) ~= 12 KHz
+PWMConfig auxPwmConfig = {
+    48'000'000,
+    1 << 12,
+    nullptr,
+    {
+        {PWM_OUTPUT_ACTIVE_HIGH | PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH, nullptr},
+        {PWM_OUTPUT_ACTIVE_HIGH | PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH, nullptr},
+        {PWM_OUTPUT_ACTIVE_HIGH | PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH, nullptr},
+        {PWM_OUTPUT_ACTIVE_HIGH | PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH, nullptr}
+    },
+    0,
+    0,
+#if STM32_PWM_USE_ADVANCED
+    0
+#endif
+};
+
+static Pwm auxDac(AUXOUT_DAC_PWM_DEVICE);
+
+extern float clampF(float min, float clamp, float max);
+
+void SetAuxDac(int channel, float voltage)
+{
+    voltage = voltage / AUXOUT_GAIN;
+    auto duty = voltage / VCC_VOLTS;
+    duty = 1.0 - duty;
+    duty = clampF(0, duty, 1);
+
+    auxDac.SetDuty(channel ? AUXOUT_DAC_PWM_CHANNEL_1 : AUXOUT_DAC_PWM_CHANNEL_0, duty);
+}
+
+/* TODO: merge with some other communication thread? */
+static THD_WORKING_AREA(waAuxOutThread, 256);
+void AuxOutThread(void*)
+{
+    while(1)
+    {
+        SetAuxDac(0, GetLambda());
+
+        chThdSleepMilliseconds(10);
+    }
+}
+
+void InitAuxDac()
+{
+    auxDac.Start(auxPwmConfig);
+
+    SetAuxDac(0, 0.0);
+    SetAuxDac(1, 0.0);
+
+    chThdCreateStatic(waAuxOutThread, sizeof(waAuxOutThread), NORMALPRIO, AuxOutThread, nullptr);
+}
+
+#endif
diff --git a/firmware/auxout.h b/firmware/auxout.h
new file mode 100644
index 0000000..c78ea7d
--- /dev/null
+++ b/firmware/auxout.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include <cstdint>
+
+void InitAuxDac();
+void SetAuxDac(int channel, float voltage);
diff --git a/firmware/boards/f1_rev2/io/io_pins.h b/firmware/boards/f1_rev2/io/io_pins.h
index ad6afee..aba3891 100644
--- a/firmware/boards/f1_rev2/io/io_pins.h
+++ b/firmware/boards/f1_rev2/io/io_pins.h
@@ -26,6 +26,13 @@
 #define PUMP_DAC_PWM_DEVICE PWMD2
 #define PUMP_DAC_PWM_CHANNEL 1
 
+// TIM1 - DAC for AUX outputs
+#define AUXOUT_DAC_PWM_DEVICE       PWMD1
+// PB14 - TIM1_CH2N
+#define AUXOUT_DAC_PWM_CHANNEL_0    1
+// PB15 - TIM1_CH3N
+#define AUXOUT_DAC_PWM_CHANNEL_1    2
+
 #define ID_SEL1_PORT                GPIOC
 #define ID_SEL1_PIN                 13
 
diff --git a/firmware/boards/f1_rev2/mcuconf.h b/firmware/boards/f1_rev2/mcuconf.h
index 6512bfa..feccd54 100644
--- a/firmware/boards/f1_rev2/mcuconf.h
+++ b/firmware/boards/f1_rev2/mcuconf.h
@@ -133,8 +133,8 @@
 /*
  * PWM driver system settings.
  */
-#define STM32_PWM_USE_ADVANCED              FALSE
-#define STM32_PWM_USE_TIM1                  FALSE
+#define STM32_PWM_USE_ADVANCED              TRUE
+#define STM32_PWM_USE_TIM1                  TRUE
 #define STM32_PWM_USE_TIM2                  TRUE
 #define STM32_PWM_USE_TIM3                  FALSE
 #define STM32_PWM_USE_TIM4                  TRUE
diff --git a/firmware/boards/f1_rev2/wideband_board_config.h b/firmware/boards/f1_rev2/wideband_board_config.h
index de916dd..71b3529 100644
--- a/firmware/boards/f1_rev2/wideband_board_config.h
+++ b/firmware/boards/f1_rev2/wideband_board_config.h
@@ -35,3 +35,9 @@
 //    Nernst voltage & ESR sense
 // *******************************
 #define VM_RESISTOR_VALUE (0)
+
+// *******************************
+//          AUX outputs
+// *******************************
+// OpAmp with 82K + 160K
+#define AUXOUT_GAIN         ((82.0 + 160.0) / 160.0)
diff --git a/firmware/main.cpp b/firmware/main.cpp
index 769a3bc..905f753 100644
--- a/firmware/main.cpp
+++ b/firmware/main.cpp
@@ -9,6 +9,7 @@
 #include "sampling.h"
 #include "uart.h"
 #include "io_pins.h"
+#include "auxout.h"
 
 using namespace wbo;
 
@@ -25,6 +26,10 @@ int main() {
     StartHeaterControl();
     StartPumpControl();
 
+#ifdef AUXOUT_DAC_PWM_DEVICE
+    InitAuxDac();
+#endif
+
     InitCan();
 #ifdef ECHO_UART
     InitUart();