As I have mentioned in my previous post (EnergySaverHighScore - Bernhard - Design for A Cause 2021 #3 - Setup Raspberry Pi ) I am going to control a power outlet to do some charging of batteries when plenty of energy is available. The main controller for this device is the Arduino Nano.
The following block diagram shows my system:
The system is connected to a (uncontrolled) power outlet. But it might also be directly connected to the grid in a distribution cabinet or completely mounted in the cabinet. Grid power is switched by a relay. I also mentioned the option to include a power meter and measure the energy delivered. I will add this in a further blog post. Finally a power outlet is connected to the relay. There the battery charger is plugged in.
Additionally there is a power supply (PSU) in the system to supply the electronics. It generates 12 V which is needed by the relay. The input voltage for the Arduino (5V) is generated by a linear regulator. This could be replaced by a switching regulator to save power in future revisions.
The coil of the relay needs 12 V. This is switched by a small transistor which is connected to pin D4 of the Arduino Nano.
The following photo shows the setup:
The Software will be explained in my following blog post.