From ae29743a5a9a0159d1e8ec0064a7207171eade0e Mon Sep 17 00:00:00 2001
From: Julien Oculi <xdrz.jot.sr@gmail.com>
Date: Tue, 10 Jun 2025 23:00:45 +0200
Subject: [PATCH] doc: update and improve readme

---
 README.md | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 675e3b9..1e00d72 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ Code de la tourelle de pointage laser du projet bouchons EDF.
 > [!IMPORTANT]
 > Nouvelle méca, les axes H/x et V/y sont découplés.
 
-# Usage
+## Usage
 
 Compile through Arduino IDE or equivalent.
 
@@ -16,6 +16,22 @@ Compile through Arduino IDE or equivalent.
 > Add [kissStepper](https://github.com/risitt/kissStepper) to your project
 > librairies.
 
+## Conventions
+
+- **x** is the horizontal axis centered at 0 and going from left (min value) to
+  right (max value).
+- **y** is the vertical axis centered at 0 and going from bottom (min value) to
+  top (max value).
+- **z** is the distance between the turrent and the target.
+
+```mermaid
+xychart-beta
+  title "Turret coordinate system"
+  x-axis "X axis [m]" -3 --> 3 
+  y-axis "Y axis [m]" -3 --> 3
+  bar [-4]
+```
+
 ## Development
 
 Required dependeinces if not using