Blog Two: Adding a UPS to the System

 

The Raspberry Pi Zero is currently powered by a five volt supply which plugs into mains power. If the mains power fails, power to the Pi would be lost. In this blog we will learn how to power the panel and Raspberry Pi Zero from a UPS, or uninterruptable power supply.

 


Figure 1 Battery UPS

In figure 1 above, a 12 volt battery is connected to J1 and a 13.5V AC to DC power supply is connected to J2. Switching power supply U1 is a five volt six amp voltage regulator and voltage regulator U2 is a 12 volt 5 amp voltage regulator. Switch SW1 is the power on / off switch which switches the regulators off by grounding the control pin of the regulators. This switch can be any toggle or rocker switch. Switch SW2 shorts out D1 so that the 13.5 volts can charge the battery. This switch should be capable of switching about 3 amps. To charge the battery, first turn off the regulators with SW1 and then turn on the charge switch SW2. Battery voltage should be checked under load (SW2 open) from time to time and after a power failure.

 

The circuit has two outputs. Connector J3 supplies twelve volt power to the system as well as a five volt auxiliary output. The remaining connector is a USB A female connector. This connector allows the Raspberry Pi to be connected to the UPS with a standard Raspberry Pi power cable.

 

The charging circuit is designed to charge a sealed lead acid battery only.

 

Comments

Post a Comment

Popular posts from this blog

Image
  Blog Three: Adding Additional Ports   The following blog contains some ideas and suggestions for improving your alarm system.   The MCP23017 I/O Expander:   The expander board is based on the MCP23017 port expander integrated circuit. The device comes with sixteen ports which can be configured as either inputs or outputs.   The I/O Expander Board:   The proposed expander board will have eight inputs and eight outputs. The inputs are identical to the ones on the main board and come with the same antitamper features. The eight outputs of the IC are connected to solid state, optically isolated relays. Each relay is capable of sinking twenty four volts at two amps, or forty-eight watts. This should be more than enough to drive mechanical relays, solenoids or relays.   Figure 9- 1 . Port Expander IC Figure 9-1 shows the connections to the MCP23017 port expander IC. Connectors J1 and J2 connect to the I2C bus which provides powe...
Read more
  Blog One: Adding a Video Camera   Install the video capture Software:   Install the software with the following command: sudo apt install motion. This will install a program called Motion which is a light weight video capture package compatible with the Raspberry Pi Zero. The command will create several files and directories. The capture software can be configured by editing the motion.conf file which can be found in the /etc/motion/ directory.   Motion.conf:   # # This config file was generated by motion 4.5.1 # Documentation:   /usr/share/doc/motion/motion_guide.html # # This file contains only the basic configuration options to get a # system working.   There are many more options available.   Please # consult the documentation for the complete list of all options. #   ############################################################ # System control configuration parameters #############################...
Read more
Image
Raspberry Pi 3 Development System   This is the development system I used to write the code for the alarm system. The code was later tested using a Raspberry Pi Zero W system. Main Board
Read more