I had a ESP8266 module called Witty Cloud , and it has no 3.3V output. I was hesitant to connect the TB6612FNG motor driver to 5V, and have the ESP run on it's 3.3V, although there is no signals going "back" to the ESP. But it could fail to sense the ESP 3.3V high output as high in a 5V system, so I thought, I will just power the driver with a GPIO pin, and this way the driver will be 3.3V also. I wanted the minimal connections, I was just curious about the single Li-Ion cell powering the motors.
Looking at the drivers pinouts, it needs 7 data inputs, two of them PWM, and two power inputs. Well, the Witty has a lot of things connected at it's GPIOs: RGB led, LDR, buttons. But there were 3 GPIOs unconnected to other things. OK, one will provide power, and it will be, at the same time, the "kill-switch". Two will be the PWM signal for the motors, an the direction pins will be "hard-coded" :) as the stand-by pin.
I had a spare power bank, and wanted to use it as a power supply. Opened it, and snapped crocodile clips to the power connectors for the battery. Connected the 5V out to ESP micro USB. The electronics is finished.
Now this is the ultimate Quick'N'Dirty method. Don't try this at home :)
Installed the Blynk Server Edition (really just started a .jar file), installed Blynk app on phone, programmed a basic Blynk sketch (it just starts the Blynk on the ESP). In the app, I made a button and two sliders, the on/off switch and the motors RPM controller. It looks like this:
(how to embed the video? it seams I can't figure it out. help appreciated)
Since the test, the NodeMCU has arrived. It has a 3.3V out, so it will go in the robot. The Witty will go in the controller.