UPS and power mobility for a Raspberry Pi
I. Pi-UpTimeUPS Overview
Pi-UpTimeUPS is an Uninterrupted Power Supply (UPS) for a Raspberry Pi. Pi-UpTimeUPS fits snugly on top of a Raspberry Pi making the Raspberry Pi mobile by providing a power source for extended period of time.
Pi-UpTimeUPS provides the following capabilities:
1) Battery backup power and UPS. Pi-UpTimeUPS provides continuous operations for up to twelve (12) hours using two 18650-3000 mAh fully charged batteries (as measured on a Pi-3 model B board.) The run time will vary depending on the model of the Raspberry Pi being used and the peripherals connected to the Raspberry Pi. Batteries take approximately 5 hours to charge. The time can be extended by using larger capacity batteries.
2) Provides steady power to the Raspberry Pi. Pi-UpTimeUPS protects the Raspberry Pi from brown-outs as well as power failures preventing unwanted downtime. Pi-UpTimeUPS accepts power input from an external power source and charges its batteries at the same time it provides clean uninterrupted power to Raspberry Pi. The same power source to a Raspberry Pi can be used with the Pi-UpTimeUPS board.
3) Automatic recharge. Pi-UpTimeUPS recharges the battery when the power comes back on after a failure.
4) Auto shutdown. Software provided with Pi-UpTimeUPS monitors the battery charge level and shuts down the Pi when the battery level is low. This software is downloaded from www.piuptime.com ‐ instructions on how to set it up can also be downloaded from the same web site.
5) Twelve analog to digital conversion (ADC) ports. Pi-UpTimeUPS provides twelve analog ports to collect data from analog sensors such as voltage sensors, current sensors, stress / strain sensors and more – complementing the GPIO capability on the Raspberry Pi. The ADC chip used provides 16 bit accuracy. We recommend using the Pi-UpTimeUPS-BO board which provides easy connections to ADC ports as well as the GPIO ports. Each port has one solderless connection. A minimum of two additional solder connections are also provided on the board. Please see additional details on Pi-UpTimeUPS-BO board for more details.
Pi-UpTimeUPS-BO provides solder and solderless connections to GPIO pots on the Raspberry Pi as well as to the ADC on the Pi-UpTimeUPS board. 3.3V and 5V power source is also provided from the UPS power supply so that the sensors and other devices connected to the board continue to operate. The Pi-UpTimeUPS-BO allows both analog and digital sensors to be connected together on one board.
6) Power Reset switch. Pi-UpTimeUPS allows a restart of the Raspberry Pi. With Pi-UpTimeUPS, there is no need to plug or unplug the external power source to reset the Pi. A Power-Reset switch on Pi-UpTimeUPS resets the Pi after a shutdown. A red LED flashes to signal the Pi reset.
7) Battery Protection. The battery is protected in several ways:
- A temperature sensor monitors the temperature and suspends charging operation if the temperature rises to unsafe levels.
- An onboard chip protects the batteries from over charging or over discharging ‐ both of which could damage the batteries.
- The battery charging circuitry manages the charge level so that the batteries remain charged.
- The charge power level is maintained so that the Raspberry Pi and its peripherals get the priority in operation over battery charging. Thus, if the Raspberry Pi demands more power, the battery provides it and resumes charging after the demand for the additional power is fulfilled.
- A fuse protects the 3.3V and 5V power supply to protect against short circuits.
The protections not only protects the battery from damage, it also extends the useful life of the battery.
8) Software. Python code provided for download for Pi-UpTimeUPS includes sample code for using the analog ports. Instructions are also provided for setting up the RTC. The software can be downloaded from the web as well.
9) UPS power sources: 3.3V and 5V UPS power is provided. Note the 3.3V power is not tapped from the Raspberry Pi. It is regenerated from the UPS and the batteries. A maximum of 800 mA of power can be drawn from the 3.3V power source.
- Industry Standard Batteries. Pi-UpTimeUPS uses standard 18650 rechargeable batteries instead of custom batteries. Replacement batteries are widely available. Batteries are not included.
- Mounting holes and standoffs provide mechanical stability of the Raspberry Pi and Pi-UpTimeUPS assembly. This ensures the batteries or the board does not fall off.
- Fuse and Power Protection. A temperature sensitive and current sensitive fuse protects exposed 5V and Ground ports on the terminal block for the analog ports.
- Temperature monitoring. The battery charging chip monitors the battery temperature and shuts the charging off if the batteries get too hot. This further protects the batteries.
- Auto shutoff – python code can shut down the system when the battery level runs low. The python code can be run as a cron job to monitor the health. See FAQ for more details.
- Works with all current models of the Raspberry Pi using a 40 pin header.This includes Raspberry Pi-3, Pi-2 and other. Older models with a 26 pin header will not work with this board.
- Uses the I2C bus – allows other peripherals to work with your application.The I2C bus on the Pi is shared with other I2C peripherals. Twenty-seven different I2C addresses can be set using the onboard jumpers. This virtually guarantees interoperability on the I2C bus with other peripherals present on the bus.
- On-board LED’s shows the status of Pi-UpTimeUPS. A red LED indicates a reboot and glows when the Power Reset switch is pressed. See our FAQ for more information on other LED’s.
- Compatible – compatible with other boards and follows the Raspberry Pi HAT format for mounting holes, headers etc.
Typical Pi-UpTimeUPS + Pi-UpTimeUPS-BO applications
UPS. Pi-UpTimeUPS provides protection against brown outs as well as power failure. When the power fails there is no interruptions to the normal operations of the Raspberry Pi. Depending on the batteries used, the run time could be as much as 16 hours (some of the older models or Pi) to as little as 12 hours (e.g. a Pi-3 with WiFi and Bluetooth operational.) The run time will depend on the battery capacity (mAh) and the peripherals connected to the Pi. Run time will be longer if larger capacity batteries are used. Battery charge time is approximately 5 hours.
Data Logging and remote Data Loggers. Pi-UpTimeUPS enhances capabilities of the Raspberry Pi for data logging applications and for remote data loggers. If not power source is available readily, the batteries can be recharged in the day using a 5V solar panel or other renewable energy sources (e.g. wind turbines.)
Mobility. Pi-UpTimeUPS is a compact, rechargeable power source makes the Pi mobile. Many applications such as digital cameras, game controllers, portable oscilloscopes, mobile phones, drones and more are made possible using Pi-UpTimeUPS.
Security and Surveillance. Pi-UpTimeUPS ensures that the security and surveillance applications you create have the necessary power and as well as an accurate time stamp. Pi-UpTimeUPS works well with the Raspberry Pi Camera – providing necessary power to the camera as well as the Raspberry Pi for continued security and surveillance – even when the power fails.
Robotics. Pi-UpTimeUPS provide a compact, stackable power source making it ideal for robotics. The total capacity of 5200 mAh (two batteries, each rated for 2600 mAh) can run a robot for a long time.
Drones. The Li-Ion 18650 batteries provide one of the best power densities in the industry today. For drones, power source and weight is of concern. Pi-UpTimeUPS offers the best power density, harnessed securely to a Raspberry Pi in the industry today.
IoT devices. IoT devices uses sensors. Some of the sensors are digital. Some of them analog. With Pi-UpTimeUPS and the Pi-UpTimeUPS-BO board, both analog and digital sensors can be connected. The data is read over an I2C bus. Sample code for the ADC shows how the information can be gathered several times a second. Building an IoT prototype or IoT device is made fast and easy.
Power Mobility. The UPS function for the Pi-UpTimeUPS makes the Raspberry Pi mobile. The Pi is no longer dependent on the power outlet. No need to shutdown and reboot the Pi every time you want to take it with you to school or to work or to your friend’s house or anywhere else. If a power outlet is available, use it and enjoy extended run time. If a power outlet is not available, simply connect a 5V solar panel and extend the time away from the power outlet.
What else can you use Pi-UpTimeUPS for? Raspberry Pi has created an amazing ecosystem. It is refreshing to see many different applications users are creating; how students use the Raspberry Pi to enhance programming skills, and how the Raspberry Pi is used for a variety of low cost computing needs. We believe that using Pi-UpTimeUPS, many Raspberry Pi applications will be created more quickly and easily.
II. Using Pi-UpTimeUPS and other boards (HATs / shields)
Pi-UpTimeUPS uses the header pins of the Raspberry Pi to provide power to the Pi. As long as the other boards follow the Raspberry Pi Foundation standards for connections, Pi-UpTimeUPS will work with these boards.
III. Pi Models Supported
By default, we ship the larger, 40 pin connectors which works with the Raspberry Pi+ (models A+, B+, Pi-2 and Pi-3). Pi-Zero is also supported, as long as a 40 pin header is soldered onto the Pi-Zero. The mounting holes for the standoff for Pi-zero are such that only two standoffs can be connected. Note that the Pi-UpTimeUPS board will extend beyond the dimensions of the Pi-Zero board.
Older models of the Raspberry Pi with a 26 pin header are not supported