diff --git a/arduino/README.md b/arduino/README.md
index a7508672..b73916fb 100644
--- a/arduino/README.md
+++ b/arduino/README.md
@@ -1,32 +1,20 @@
-This code is used on the STM32 acting a payload to the CubeSat Simulator.
+This code is for the STM32 or Pro Micro acting a payload to the CubeSatSim.
 
-The interface is via the Serial1 port on the STM32 (pins PA9 and PA10) and the Raspberry Pi UART (pins 8 and 10)
+Code that runs on both boards is in this directory.  Code that only runs on a particular board is in the directory for that board.
 
-The STM32 can be programmed using the Arduino IDE with the Generic STM32F103C series board and STM32duino bootloader, Maple Mini port.
-
-On the Raspberry Pi, to enable the UART:
-
-sudo nano /boot/config.txt
-
-Add the following line:
+Code includes:
 
-dtoverlay=pi3-miniuart-bt
+i2c_scanner.ino  A handy utility for scanning the I2C bus that displays the results in the Serial Monitor at 9600 baud.  If the sensors are installed and the jumpers set to the correct position, the two sensors should be displayed.
 
-Edit cmdline.txt:
+blink_stm32.ino and blink_pro_micro.ino  The usual Arduino "Hello World" application that blinks the LED.
 
-sudo nano /boot/cmdline.txt
+bme280_test.ino
 
-Remove the following text in cmdline.txt to prevent a console from running on the serial port:
+mpu6050_test.ino
 
-console=serial0,115200
-
-then reboot.  You can test it with minicom:
-
-sudo apt-get install minicom
-
-minicom -b 9600 -o -D /dev/serial0
+The STM32 can be programmed using the Arduino IDE with the Generic STM32F103C series board and STM32duino bootloader, Maple Mini port.
 
-Type Control-A, then X, then Return to exit.
+The Sparkfun Pro Micro can also be programed using the Arduino IDE with the Sparkfun Pro Micro board and AVRISP mkII Programmer.
 
 See https://github.com/alanbjohnston/CubeSatSim/wiki/Arduino-Payload for ideas on using the Arduino as a payload for the CubeSat Simulator.