Update the URLs seismicmatt.com to mattoppenheim.com

README.md

@@ -234,7 +234,7 @@ The following extensions can be added into MakeCode by copying the GitHub URL an
 
 - [PlatformIO](https://docs.platformio.org/en/latest/boards/nordicnrf51/bbcmicrobit.html) - Embedded IDE with support for the micro:bit using the Arduino or Mbed software stack.
 - [COMPX318 micro:bit Compiler](https://peer-compile.cms.waikato.ac.nz) - Upload a single source file to be compiled online with the DAL C/C++ toolchain and download the resulting hex file.
-- [Eclipse Instructions](https://www.seismicmatt.com/2018/05/04/eclipse-yotta-c-c-and-the-bbc-microbit/) - Setting up Eclipse with Yotta to build and debug with the BBC micro:bit.
+- [Eclipse Instructions](https://mattoppenheim.com/2018/05/04/eclipse-yotta-c-c-and-the-bbc-microbit/) - Setting up Eclipse with Yotta to build and debug with the BBC micro:bit.
 
 ##### ©️ C/C++ Libraries
 
@@ -579,7 +579,7 @@ Useful Articles for developing on the micro:bit.
 - [IoT Cloud Access with micro:bit over BLE for Remote Sensing](https://www.hackster.io/PSoC_Rocks/iot-cloud-access-with-micro-bit-over-ble-for-remote-sensing-351938) - Program BBC micro:bit with mbed OS and remotely send data to cloud by utilizing BLE to smartphone/PC IoT cloud gateway.
 - [Network Rivalry: a Low-Latency Game for the BBC micro:bit](https://www.instructables.com/id/Network-Rivalry-a-Low-Latency-Game-for-the-BBC-Mic/) - Tutorial explaining how to implement a basic multiplayer game on the BBC micro:bit.
 - [Circuit Lumber Punking](https://www.instructables.com/id/Circuit-Lumber-Punking/) - Creating micro:bit circuit boards in timber.
-- [Measuring the BBC micro:bit LED current draw](https://www.seismicmatt.com/2019/03/06/measuring-the-bbc-microbit-led-current-draw/) - Looking at the voltage and current supplied to the BBC micro:bit for different numbers of active LEDs.
+- [Measuring the BBC micro:bit LED current draw](https://mattoppenheim.com/2019/03/06/measuring-the-bbc-microbit-led-current-draw/) - Looking at the voltage and current supplied to the BBC micro:bit for different numbers of active LEDs.
 - [micro:bit <-> Raspberry Pi](https://ukbaz.github.io/howto/ubit_workshop.html) - An introduction on how you can exchange information between a micro:bit and a Raspberry Pi using Bluetooth Low Energy (BLE).
 - [WiFi Web Server on BBC micro:bit and ESP-01](https://www.hackster.io/alankrantas/wifi-web-server-on-bbc-micro-bit-and-esp-01-esp8266-498e0d) - Create a micro:bit web server via AT commands to an ESP8266 which can respond to web browser requests over WiFi.
 - [IoT Cloud Access with micro:bit over BLE for Remote Sensing](https://www.hackster.io/PSoC_Rocks/iot-cloud-access-with-micro-bit-over-ble-for-remote-sensing-351938) - Program the BBC micro:bit with Mbed OS and remotely send data to the cloud by utilizing BLE to smartphone/PC IoT Cloud Gateway.