title: Python Serial Communication Using HC-05 Connected to OS X Version 10.11.1 (15B42)
body: <p>this is my first post on stack overflow yet I use it all the time to solve my many programming issues. So first off, thank you for any help that is given. </p>
  
  <p>I have been given a task by my advisor to get HC-05 sending and receiving serial comms with python and I am at my wits end on the final part of getting it up and running. I have searched everything I possibly can and have not yet found the answer, or even a similar issue. I have the comms working somewhat well. My baud rate is set at 115200 and have that matched in python serial. I am using an Arduino to gather values from sensors on a robot, send the values to python over serial to run calculations then have the result send back.  I am sending two values and only receiving one. I first got it up and running by using serial comms over usb cable and it works perfect. I then made a few alterations to get it sending over bluetooth. The data that is being sent from the Arduino through bluetooth is perfect. When I do calculations and send the result back, however, the values are off. I have a timer Interrupt Service Routine (ISR) running on the Arduino that sends the values at 100Hz. If I slow that down to 10Hz, the response from computer to Arduino gets better and if I slow it down to 1HZ it is perfect. Unfortunately, I really need it to be working well at 100Hz for accurate control of my robot. I have included a link below of a plot of the response at 10Hz. Alpha and Theta are values sent from Arduino, V is a calculation done by python and V_echo is V being sent to Arduino, multiplied by 2 and sent back to python. As you can see, V_echo is broken and jagged when it should be a smooth line like the others. All of this tells me that while the send rate of the HC-05 is fine, the receive rate is too slow. I have changed baud rate possibilities, played with making the HC-05 a master vs. slave and slave-loop... slave works the best. The last thing I can think of is using stop bits. I have pyserial sending two stop bits and have the HC=05 stop bit set to two by using AT+UART=115200,1,0. If stop bits are my solution, I clearly have it set up wrong. I don't know exactly what python does when I include stop bits and furthermore I don't know if I need to do any program that reads the bit or if the HC-05 just understands it... If stop bits are not my answer, I look forward to finding out what is. Thanks again.</p>