diff --git a/3dprint/DESIGN.md b/3dprint/DESIGN.md
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+++ b/3dprint/DESIGN.md
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+# 3d Print case designs
\ No newline at end of file
diff --git a/3dprint/UnoDin/UnoDin.blend b/3dprint/UnoDin/UnoDin.blend
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diff --git a/3dprint/UnoDin/UnoDin.stl b/3dprint/UnoDin/UnoDin.stl
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index 0000000..49a9074
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diff --git a/firmware/modbus-sd/README.md b/firmware/modbus-sd/README.md
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+# Modbus SD Card Firmware
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diff --git a/firmware/modbus-sd/modbus-sd-01.ino b/firmware/modbus-sd/modbus-sd-01.ino
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+++ b/firmware/modbus-sd/modbus-sd-01.ino
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+#include <Wire.h>
+#include <RTClib.h>
+
+#include <ModbusRtu.h>
+#include <SoftwareSerial.h>
+
+#include <SD.h>
+#include <SPI.h>
+
+#define DE_RE_PIN 4
+#define RX_PIN 6     // SoftwareSerial RX pin
+#define TX_PIN 8     // SoftwareSerial TX pin
+#define SD_CS_PIN 10 // Chip Select for SD Card
+
+RTC_DS3231 rtc; // Create an RTC object
+File dataFile;
+
+SoftwareSerial modbusSerial(RX_PIN, TX_PIN); // Create a software serial instance
+Modbus slave(1, modbusSerial, DE_RE_PIN);
+uint16_t holdingRegisters[20]; // Array to hold Modbus registers
+
+void setup()
+{
+    Serial.begin(9600); // For debugging
+    Serial.println("Startup \n");
+
+    // Initialize RTC
+    if (!rtc.begin())
+    {
+        Serial.println("Couldn't find RTC\n");
+    }
+
+    if (rtc.lostPower())
+    {
+        Serial.println("RTC lost power, let's set the time!\n");
+        // Comment out the following line once the time is set to avoid resetting on every start
+        rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
+    }
+    Serial.print("Time: ");
+    Serial.print(rtc.now().timestamp());
+    Serial.println("\n");
+
+    // Initialize SD card
+    Serial.println("SD card initializing...");
+    pinMode(SD_CS_PIN, OUTPUT);
+    if (!SD.begin(SPI_HALF_SPEED, SD_CS_PIN))
+    {
+        Serial.println("SD card initialization failed!\n");
+        return;
+    }
+    Serial.println("SD card initialized.\n");
+
+    Serial.println("Initialize RS485 module / Modbus \n");
+    // Initialize RS485 module
+    // Initialize DE and RE pins
+    pinMode(DE_RE_PIN, OUTPUT);
+    digitalWrite(DE_RE_PIN, LOW); // Set to LOW for receiving mode initially
+
+    slave.start();
+
+    // Initialize the holding registers
+    // holdingRegisters[0] = 0x0000;
+    // holdingRegisters[1] = 0x0000;
+}
+
+void writeFile(char *str)
+{
+    if (!dataFile)
+    {
+        Serial.println("Error opening file");
+        return;
+    }
+    DateTime now = rtc.now();
+    // Log the current date and time
+    dataFile.print(now.year(), DEC);
+    dataFile.print('-');
+    dataFile.print(now.month(), DEC);
+    dataFile.print('-');
+    dataFile.print(now.day(), DEC);
+    dataFile.print(" ");
+    dataFile.print(now.hour(), DEC);
+    dataFile.print(':');
+    dataFile.print(now.minute(), DEC);
+    dataFile.print(':');
+    dataFile.print(now.second(), DEC);
+    dataFile.print(",");
+    dataFile.print(str);
+
+    dataFile.println();
+}
+
+String getFilename()
+{
+    DateTime now = rtc.now();
+    String mb = "";
+    mb += now.year();
+    mb += now.month();
+    mb += now.day();
+    mb += ".csv";
+
+    return mb;
+}
+
+void loop()
+{
+    Serial.print("Time: ");
+    Serial.print(rtc.now().timestamp());
+    //   Serial.print("\nHeep:");
+    //  Serial.print(ESP.getFreeHeap());
+    Serial.print("\n");
+
+    // Open file for writing
+    String filename = getFilename();
+    Serial.print("Open Card ");
+    Serial.print(filename.c_str());
+    Serial.print("\n");
+
+    dataFile = SD.open(filename.c_str(), FILE_WRITE);
+
+    Serial.print("Error count ");
+    Serial.print(slave.getErrCnt());
+    Serial.print("\n");
+    Serial.print(slave.getLastError());
+    Serial.print("\n");
+
+    //
+    const int result = slave.poll(holdingRegisters, 20);
+    String mb = "modbus,";
+    mb += result;
+    mb += ",";
+    for (int i = 0; i < 20; i++)
+    {
+        mb += holdingRegisters[i];
+        mb += ",";
+    }
+
+    Serial.println(mb.c_str());
+    writeFile(mb.c_str());
+
+    if (modbusSerial.available() > 0)
+    {
+        Serial.println(modbusSerial.read());
+    }
+
+    if (dataFile)
+    {
+        dataFile.close(); // Close the file
+        Serial.print("Data written to SD card: ");
+        Serial.print(filename.c_str());
+        Serial.print("\n");
+    }
+
+    Serial.print("\n\n");
+
+    delay(1000); // Delay between readings
+}
diff --git a/firmware/modbus-sim/README.md b/firmware/modbus-sim/README.md
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--- /dev/null
+++ b/firmware/modbus-sim/README.md
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+# Modbus Sim Card Firmware
\ No newline at end of file