From 1a582815ba218d2a9047abae92b9f33a3301ffd5 Mon Sep 17 00:00:00 2001
From: Jean-François Milants <jf@codingfield.com>
Date: Sun, 10 Jan 2021 17:57:26 +0100
Subject: First implementation of the HR sensor using 100% foss code (ported
 from waspos)

---
 src/components/heartrate/Biquad.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 src/components/heartrate/Biquad.h

(limited to 'src/components/heartrate/Biquad.h')

diff --git a/src/components/heartrate/Biquad.h b/src/components/heartrate/Biquad.h
new file mode 100644
index 00000000..dc9b97f6
--- /dev/null
+++ b/src/components/heartrate/Biquad.h
@@ -0,0 +1,22 @@
+#pragma once
+
+namespace Pinetime {
+  namespace Controllers {
+    /// Direct Form II Biquad Filter
+    class Biquad {
+    public:
+      Biquad(float b0, float  b1, float b2, float a1, float a2);
+      float Step(float x);
+
+    private:
+      float b0;
+      float b1;
+      float b2;
+      float a1;
+      float a2;
+
+      float v1 = 0.0f;
+      float v2 = 0.0f;
+    };
+  }
+}
-- 
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