Soldering and Making Connections
The induction receiver coil charges the robot with no contact. This allows the robot to go to a pre-defined location on the configuration space for charging. The coil as seen in figure below, is farther away from the filter circuit. For ease of assembly, we are going to reduce the length of the wires extending from the coil. For this, we first desolder the coil from the circuit board
After this, we scrape off the insulation material (see the second figure above) for a very small length at the tip of the coil ends to ensure proper conductivity once we resolder the coil back to the circuit. It is better to check if the insulation is properly scraped using multimeter in continuity mode (you should hear a beep).
If the continuity is good, you can start soldering the coil back to the circuit as shown in figure. Remember, there is no polarity on the coil end, so you can connect either ways. Also, make sure that the wires enter from the top of the circuit and the soldering is at the bottom. And finally apply some glue.
A power booster converts 3.6V battery or USB input to a 5V output. This is typically used for powering up the Raspberry Pi from the LiPo battery on the robot. This circuit can also simultaneously charge while the battery is in use. Which means, we can connect a micro usb or a charging coil while the robot is switched on. More details on this can be found here..
The next step is to connect the output terminals of the coil to the power booster circuit. Take a moment to identify the part. Strip the terminals of the coil circuit as shown in the figure below. These terminals go to the USB and Ground inputs on the power booster circuit. These are the inputs to the power booster (micro usb and coil charging in parallel).
Get three of the following wires of around the same length as shown here. The red one should be soldered at 5V, black to the first ground (2nd pin) and the white wire with female connector to LBO. All three wires should have both tips removed and then stripped and twisted into a fine tip. The 5V terminal is the output of the power booster and should be connected to the 5V input of raspberry pi. The ground terminal is common for raspberry pi and both the servos. The LBO pin goes high when the battery is low, this goes to pin # on raspberry pi. The third photo shows how the power booster should look with all the new wires soldered correctly.
