TV REMOTE

If you cannot use the Bluetooth App, its possible to use a TV remote adapter on the Robot,
and a TV remote control. 
There is a different adapter to receive the Infra-red data:

Your program needs the following at the start
   from Bluetooth import *
   import params as p   # imports basespeed, efactor, dfactor
   BT = Bluetooth(99)    # the 99 makes the port run at the right speed

Then, inside your loops, to allow commands and data update,
include the following
   if (BT.Ready()):
        BT.Cmd()
and use the following parameters:
   p.basespeed for speed,
   p.efactor for steering strength,
   and p.dfactor for derivative.

Commands ( - single keystroke)
These select which variable to change:
s  (Vol+)
e  (Vol-)
d  (CH+)
(there are no print outs without Bluetooth)

These modify the selected variable:
0 (Zero) sets selected variable to zero
+ (Up arrow)  increases the selected variable
-  (Down arrow)decreases the selected variable (but not below zero)
1 sets the increase/decrease amount to 1
5 sets the increase/decrease amount to 5

Storage of variables:
w (ok or Blue) saves the variables to file params.py so they will survive power-down
r (Green ) re-reads variables from file params.py
   - Go back to last saved set.

These two send outputs to the Thonny screen
? (Menu) gives this list of commands,
q (av) prints out all variable values.