07. Base Station
The base station includes both a docking/charging station and the BWF sender. Both are driven by the same power supply which ideally is running at 15V and with a current capacity of 0.4 - 1 A.
There are two versions of the BWF sender. The standalone or the integrated version. They both use the same software, found at BWF Transmitter.
##Integrated In the integrated version, a normal motor shield, same type as the one used to drive the wheelmotors in the mower, is used together with the Arduino to drive the BWF.
The BWF is just connected to the same points as the wheel motor. Use output A. Drive both the shield and arduino through the power input on the shield.
To run this version of the sender, you need to enable option 2 in the program for the arduino:
// Select which transmitter type you have by uncommenting that line
//#define __1_L298_Standalone__
#define __2_L298_Shield__
//#define __3_L293_Shield__
//#define __4_MegaMoto_Shield__
Here is a Video of the installation.
There are standalone versions available of the L298 driver chip. These have the advantage that they normally can be driven at higher voltages than 15V for more power. Handy if you have a larger lawn (1000m2 or similar) which needs cutting. Since the cable is so long, more voltage is normally needed to get a powerful enough signal in the wire.
Another advantage with the standalone version is that there is normally a 5V power outtake from the board. This outtake can be used to drive the arduino controller which in this case does not have to be an UNO format. An arduino nano, micro or other type can be used as well.
The standalone version is the default setting in the transmitter program (option 1). The IN1, IN2, IN3 and IN4 are to be connected to the A0-A4 pins on the arduino. Be sure to drive the arduino from the 5V outtake. Especially if you are running at higher voltages than 15V. To drive the arduino just connect GND to GND on the board and the 5V outtake to the VIN pin on the arduino.
Here is a Video of a standalone installation
Splice the power supply to the transmitter and connect the plus and minus to respective charge plates.
There are no sure designs here, just that the plates should connect to something corresponding on the mower when docking. We have found that having a wedge form of the base station helps significantly in the docking robustness because the mower self-aligns and the wedge form secures a good contact pressure.
The plates are listed in the BOM as Klamsvep. The main thing is that they are made out for copper which is a good conductor. Bad conductors are among others, stainless steel so try to avoid solutions with this material.