95 lines
3.8 KiB
Markdown
95 lines
3.8 KiB
Markdown
# Introduction
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This is the source files folder for the EasyDccMouse.
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EasyDccMouse is a system to remote control DCC scale locomotive, it is based on a ESP32 with tft display, touch screen, encoder and battery.
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EasyDccMouse sends actions to a DCC centrale station.
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```
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+------------------------------------------------------+
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| [O] [⇄] [ID] [⚡] | <-- Header with 4 icons:
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| ON Dir DCC Power | [O] Status (ON/OFF)
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| | [⇄] Direction (Forward/Reverse)
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| [================== Train ===================] | [ID] DCC id
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| | [⚡] Power/Connection
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| |██████████████████████████████████████████| | <-- Model picture (190x40 px)
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| |
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| ___ |
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| .-' '-. |
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| .' '. |
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| / \ |
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| | /\ /\ | | <-- Speedometer (arc + needle)
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| | / \ / \ | |
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| | / \_/ \ | |
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| |/ \| |
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| '---------------' |
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| | | |
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| Needle |
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| |
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| [F1] [F2] [F3] [F4] [F5] [F6] [F7] [F8] | <-- Function pad (row 1)
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| [F9] [F10][F11][F12][F13][F14][F15][F16] | <-- Function pad (row 2)
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+------------------------------------------------------+
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```
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# Implementation
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## How to draw speedometer with arc and needle on my TFT display?
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To draw an arc-style speedometer with a moving needle on your TFT display (e.g., ILI9341), you can use the TFT_eSPI library. Here’s a step-by-step example:
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1. **Draw the arc:**
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- Use `drawArc()` or draw multiple short lines to approximate an arc.
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- Example: Draw an arc from 135° to 45° (like a semicircle at the bottom).
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2. **Draw the needle:**
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- Calculate the angle for the needle based on the speed value.
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- Use `drawLine()` from the center of the arc to the edge at the calculated angle.
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3. **Display the speed value:**
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- Use `setCursor()` and `print()` to show the numeric speed.
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**Example code:**
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```cpp
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#include <TFT_eSPI.h>
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#include <math.h>
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TFT_eSPI tft = TFT_eSPI();
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void drawSpeedometer(int speed) {
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int cx = 120, cy = 120, r = 80; // Center and radius
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int minAngle = 135, maxAngle = 45; // Degrees
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int minSpeed = 0, maxSpeed = 100;
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// Draw arc (approximate with lines)
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for (int a = minAngle; a >= maxAngle; a -= 3) {
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float rad = a * 3.14159 / 180.0;
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int x1 = cx + (r - 10) * cos(rad);
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int y1 = cy + (r - 10) * sin(rad);
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int x2 = cx + r * cos(rad);
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int y2 = cy + r * sin(rad);
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tft.drawLine(x1, y1, x2, y2, TFT_WHITE);
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}
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// Draw needle
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float angle = minAngle - (float)(speed - minSpeed) / (maxSpeed - minSpeed) * (minAngle - maxAngle);
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float rad = angle * 3.14159 / 180.0;
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int nx = cx + (r - 20) * cos(rad);
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int ny = cy + (r - 20) * sin(rad);
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tft.drawLine(cx, cy, nx, ny, TFT_RED);
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// Draw speed value
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tft.setCursor(cx - 20, cy + 30);
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tft.setTextColor(TFT_WHITE, TFT_BLACK);
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tft.setTextSize(2);
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tft.printf("%d", speed);
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}
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```
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**Tips:**
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- Clear the previous needle before drawing a new one for smooth animation.
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- Adjust `cx`, `cy`, and `r` for your display size.
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- You can enhance the arc with tick marks and labels for a more realistic look. |