diff --git a/firmware/lux.cpp b/firmware/lux.cpp
index d6a1397..874f151 100644
--- a/firmware/lux.cpp
+++ b/firmware/lux.cpp
@@ -17,12 +17,11 @@ extern "C" {
 
 const int signal_led_pin = 2;
 
-//const int cs0 = 15;
+const int cs0 = 15;
 
 const int gpio4 = 4;
 const int gpio5 = 5;
 
-
 struct apa10xx_pixel_t {
     struct {
         unsigned int mod: 5, marker: 3;
@@ -55,7 +54,6 @@ static apa10xx_pixel_t next_color(int i) {
     return colour;
 }
 
-/*
 void spi_dac(int id, int val) {
     int dac_val = (val << 2) & 0x3FFC;
 
@@ -75,7 +73,6 @@ void spi_dac(int id, int val) {
     gpio_write(cs0, 1);
     gpio_write(cs0, 0);
 }
-*/
 
 void write_leds(apa10xx_pixel_t *arr, size_t len) {
     spi_transfer_32(1, 0x00000000);
@@ -85,11 +82,114 @@ void write_leds(apa10xx_pixel_t *arr, size_t len) {
     spi_transfer_32(1, 0xFFFFFFFF);
 }
 
+namespace fiatlux {
+
+    namespace signal {
+        void write_data(bool data) {
+            gpio_write(signal_led_pin, !data);
+        }
+    }
+
+    namespace relais {
+        void write_data(uint8_t data[2]) {
+            gpio_write(gpio4, (bool) data[0]);
+            gpio_write(gpio5, (bool) data[1]);
+        }
+    }
+
+    namespace spi_dimmer {
+        void write_data(uint16_t data[6]) {
+            for (int i = 0; i < 6; ++i) {
+                int dac_val = (data[i] << 2) & 0x3FFC;
+
+                spi_transfer_8(1, ~(0x00));
+                gpio_write(cs0, 1);
+                gpio_write(cs0, 0);
+                spi_transfer_8(1, ~(0x01 << i));
+                gpio_write(cs0, 1);
+                gpio_write(cs0, 0);
+
+                spi_transfer_16(1, dac_val);
+
+                spi_transfer_8(1, ~(0x00));
+                gpio_write(cs0, 1);
+                gpio_write(cs0, 0);
+                spi_transfer_8(1, ~(0x01 << i));
+                gpio_write(cs0, 1);
+                gpio_write(cs0, 0);
+            }
+        }
+    }
+
+    namespace ws28x {
+        void write_data(ws2812_pixel_t *data, size_t len) {
+            ws2812_i2s_init(len, PIXEL_RGBW);
+            ws2812_i2s_update(data, PIXEL_RGBW);
+        }
+    }
+
+    namespace apa10x {
+        void write_data(apa10xx_pixel_t *data, size_t len) {
+            spi_transfer_32(1, 0x00000000);
+            for (size_t i = 0; i < len; i++)
+                spi_transfer_32(1, *(uint32_t *) &data[i]);
+            spi_transfer_32(1, 0xFFFFFFFF);
+            spi_transfer_32(1, 0xFFFFFFFF);
+        }
+    }
+
+    struct hal_error_t {
+        constexpr hal_error_t() = default;
+
+        hal_error_t(const char *) {}
+
+        hal_error_t(const char *, hal_error_t *cause) {}
+    };
+
+    constexpr hal_error_t empty_error;
+
+    enum class hal_module_t {
+        SIGNAL, RELAIS, SPI_DIMMER, WS28X, APA10X
+    };
+
+    hal_error_t write_channel(uint8_t *data, size_t count, size_t stride, hal_module_t mod) {
+        if(mod == hal_module_t::SIGNAL) {
+            if(count != 1)
+                return "unsupported value for count";
+            if(stride != 1)
+                return "unsupported value for stride";
+            signal::write_data(data[0]);
+        } else if(mod == hal_module_t::RELAIS) {
+            if(count != 2)
+                return "unsupported value for count";
+            if(stride != 1)
+                return "unsupported value for stride";
+            relais::write_data(data);
+        } else if(mod == hal_module_t::SPI_DIMMER) {
+            if(count != 6)
+                return "unsupported value for count";
+            if(stride != 2)
+                return "unsupported value for stride";
+            spi_dimmer::write_data((uint16_t *) data);
+        } else if(mod == hal_module_t::WS28X) {
+            if(stride != 4)
+                return "unsupported value for stride";
+            ws28x::write_data((ws2812_pixel_t *) data, count);
+        } else if(mod == hal_module_t::APA10X) {
+            if(stride != 4)
+                return "unsupported value for stride";
+            apa10x::write_data((apa10xx_pixel_t *) data, count);
+        } else {
+            return "unsupported module";
+        }
+    }
+
+}
 
 ws2812_pixel_t **pixels_ptr;
 
 extern "C" void signal_led(bool state) {
-    gpio_write(signal_led_pin, !state);
+    fiatlux::signal::write_data(state);
 }