diff --git a/tests/hsv_tests.cc b/tests/hsv_tests.cc
new file mode 100644
index 0000000..9d5b73d
--- /dev/null
+++ b/tests/hsv_tests.cc
@@ -0,0 +1,19 @@
+#include "doctest.h"
+#include "util/hsv.hh"
+
+TEST_CASE("HSV to Color") {
+	// check primary colors
+	CHECK(Color{HSVColor{0, 255, 255}} == Colors::red);
+	CHECK(Color{HSVColor{86, 255, 255}} == Colors::green);
+	CHECK(Color{HSVColor{172, 255, 255}} == Colors::blue);
+
+	// check no saturation
+	const auto ns = Color{HSVColor{172, 0, 255}};
+	CHECK(ns.red() == ns.green());
+	CHECK(ns.red() == ns.blue());
+	CHECK(ns.red() == 255);
+
+	// check value
+	const auto v = Color{HSVColor{0, 255, 0}};
+	CHECK(v == Colors::black);
+}
diff --git a/tests/quadrature_encoder_tests.cc b/tests/quadrature_encoder_tests.cc
new file mode 100644
index 0000000..097e1a6
--- /dev/null
+++ b/tests/quadrature_encoder_tests.cc
@@ -0,0 +1,55 @@
+#include "doctest.h"
+#include "util/quadrature_encoder.hh"
+
+TEST_CASE("Quadrature Encoder") {
+
+	using Enc = QuadratureEncoder<>;
+
+	Enc encoder{};
+
+	// check clockwise
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+	CHECK(encoder.get_motion(true, true) == Enc::CW);
+
+	// check clockwise no state change
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+
+	CHECK(encoder.get_motion(true, true) == Enc::CW);
+	CHECK(encoder.get_motion(true, true) == Enc::None);
+	CHECK(encoder.get_motion(true, true) == Enc::None);
+	CHECK(encoder.get_motion(true, true) == Enc::None);
+
+	// check counter-clockwise
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+	CHECK(encoder.get_motion(true, true) == Enc::CCW);
+
+	// check with no state change
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+	CHECK(encoder.get_motion(false, true) == Enc::None);
+
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+	CHECK(encoder.get_motion(false, false) == Enc::None);
+
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+	CHECK(encoder.get_motion(true, false) == Enc::None);
+
+	CHECK(encoder.get_motion(true, true) == Enc::CCW);
+	CHECK(encoder.get_motion(true, true) == Enc::None);
+}
diff --git a/util/hsv.hh b/util/hsv.hh
new file mode 100644
index 0000000..ed49dd8
--- /dev/null
+++ b/util/hsv.hh
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "util/colors.hh"
+#include <cstdint>
+
+class HSVColor {
+public:
+	uint8_t h;
+	uint8_t s;
+	uint8_t v;
+
+	constexpr operator Color() const {
+		if (!s) {
+			return Color{v, v, v};
+		}
+
+		const auto region = h / 43u;
+		const auto remainder = (h - (region * 43u)) * 6u;
+
+		const uint8_t p = (v * (255u - s)) >> 8u;
+		const uint8_t q = (v * (255u - ((s * remainder) >> 8u))) >> 8u;
+		const uint8_t t = (v * (255u - ((s * (255u - remainder)) >> 8u))) >> 8u;
+
+		switch (region) {
+			case 0:
+				return Color{v, t, p};
+			case 1:
+				return Color{q, v, p};
+			case 2:
+				return Color{p, v, t};
+			case 3:
+				return Color{p, q, v};
+			case 4:
+				return Color{t, p, v};
+			default:
+				return Color{v, p, q};
+		}
+	}
+};
diff --git a/util/quadrature_encoder.hh b/util/quadrature_encoder.hh
new file mode 100644
index 0000000..fc28be0
--- /dev/null
+++ b/util/quadrature_encoder.hh
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <cstdint>
+
+template<bool invert = false>
+class QuadratureEncoder {
+	static constexpr uint8_t valid_ccw = 0b10000111 ^ (invert ? 0xff : 0x00);
+	static constexpr uint8_t valid_cw = 0b01001011 ^ (invert ? 0xff : 0x00);
+
+	uint8_t prev_state{};
+
+public:
+	enum Direction { None = 0, CW = 1, CCW = -1 };
+
+	Direction get_motion(bool state_a, bool state_b) {
+		const auto cur_state = state_a | (state_b << 1u);
+
+		if ((prev_state & 0b11) == cur_state)
+			return None;
+
+		prev_state <<= 2;
+		prev_state |= cur_state;
+
+		switch (prev_state) {
+			case valid_cw:
+				return CW;
+			case valid_ccw:
+				return CCW;
+			default:
+				return None;
+		}
+	}
+};