Hello everyone, first post here and new to the Arduino! I am trying to modify the code attached below to run continuously without input from the terminal but can't seem to get it to work! I have tried simply introducing a Serial.println("d,1 \r") bit of code (typing d,1 and carriage return on the serial monitor starts the pump) but that failed, with d,1 just printing out on the monitor and nothing being pumped, any ideas on how I can overcome this?
Thank you! 
I am trying to modify the code attached below
Do you understand what that code does? You have NOT removed the part that reads data from the PC, or the part that relies on that having happened.
What changes DID you make?
What I did was to comment out the received_from_computer section just leave the serial_event=true section and put in a Serial.write("d,1 \r") at the start of void loop. This resulted in me getting d,1 printed on the monitor
If you don't want "d,1" on the serial monitor, why did you write() it?
Post your (modified) code!