Example Code for Jetson Nano-Battery Voltage and Percentage Reading

Hardware Preparation

• Jetson Nano Developer Kit: 1
• DFR0865 Jetson Nano UPS Module: 1
• 18650 lithium-ion batteries: 6

Software Preparation

1. First, install the pip of Python3 on the Ubuntu system. Please run the following command as the root user or sudo user in the terminal:

sudo apt-get update
sudo apt-get install python-pip

2. Install Jetson GPIO library:

sudo pip install Jetson.GPIO

3. Install the I2C development library:

sudo apt-get install libi2c-dev i2c-tools
pip install smbus

4. Install Nano editor on Ubuntu:

sudo apt-get install nano

Wiring Diagram

Correctly install six 18650 batteries to the Jetson Nano UPS power board, and connect to Jetson Nano through the 10 Pin GPIO board. The connection diagram is as follows:

Other Preparation Work

1. Create a new file named Bat.py using the Nano editor or any text editor.
2. Copy the sample code provided into the Bat.py file.

Sample Code

#!/usr/bin/env python
import struct
import smbus
import sys
import time


def readVoltage(bus):

     address = 0x36
     read = bus.read_word_data(address, 2)
     swapped = struct.unpack("<H", struct.pack(">H", read))[0]
     voltage = swapped * 1.25 /1000/16
     return voltage


def readCapacity(bus):

     address = 0x36
     read = bus.read_word_data(address, 4)
     swapped = struct.unpack("<H", struct.pack(">H", read))[0]
     capacity = swapped/256
     return capacity


bus = smbus.SMBus(1) # 0 = /dev/i2c-0 (port I2C0), 1 = /dev/i2c-1 (port I2C1)

while True:

 print "******************"
 print "Voltage:%5.2fV" % readVoltage(bus)

 print "Battery:%5i%%" % readCapacity(bus)

 if readCapacity(bus) == 100:

         print "Battery FULL"

 if readCapacity(bus) < 20:


         print "Battery LOW"
 print "******************"
 time.sleep(2)

Run the command in the terminal to execute the code:

sudo python Bat.py

Result

Now you get the battery power percentage and battery voltage information.

Additional Information