Smart Batteries Spring 2016 – Update 1

Actual Work Done We’re done with foundation We’ve actually gotten something working SMBus Communications Interface for Hardware Charger & Operating System We’re done with foundation Raspberry Pi and Arduino Communications are set! (I2C) Minnowboard is being set up Components are almost all bought We’re starting to build up circuits We were able to connect the raspberry pi and the Arduino with I2C bus. We were able to send the data from the Arduino to the Raspberry Pi and the Raspberry pi was able to receive data and interpret the data.

Arduino The standard to all hardware prototype Communicates via SMBus to our boards Communicates with other components Intermediate between PC Board and Batteries The standard of standing standards

AT Tiny Based off the Arduino Software Has SMBus / I2C Communications Will be placed on individual batteries Holds ALL persistent data for the batteries

Minnowboard Turbot Intel x86_64 Architecture Full ACPI Compliance A PC Board that fits our bill Intel x86_64 Architecture (Very well documented) Full ACPI Compliance ACPI Debugging provisions I2C breakout available Power hungry Beast 2.5 Amp use without HDD Up to 4 with HDD

Coulomb Counter - LTC4150 Standard Run of the mill current sense Shows power going in and going out Standard method for calculating battery use and state of charge CHALLENGE: Limited at 8.5 watts (1A @ 8.5V)

18650 Lithium Cell Our first battery that we’ll work with Standard Secondary Li-Ion Cell No circuitry Very well profiled DIY’s finest

Code Written Not that much yet Python Script for SMBus communications with Arduino Based on C Library Arduino Script for SMBus Device activity Several well documented examples available Manipulation of CPUs on x86_64 Linux Linux Kernel programs offer fine control with cpufreq-set We found an Arduino script online that checks for data within the pins of arduino. We created an array of integers that simulates battery information. In the future the array will be constantly updated. Whenever the Raspberry Pi request for data, the Arduino sends the updated array of integers by I2C bus. (Van) I created a python script that gets all the information from the arduino at any time. (manny) This concept was made using master reader and slave sender configuration via I2C synchronous serial protocol. This configuration literally makes the Raspberry Pi the master while the Arduino is the slave. (manny) We have been messing around with the CPU frequency using linux commands. Most frequency scaling algorithms only offer the CPU to be set to one frequency. For dynamic frequency scaling, cpu frequency core must be able to tell these drivers of a specific frequency. That is where CPU frequency governors comes in. Some of these governors are *Performance, which sets the highest frequency (from the min, max frequencies). *PowerSave, sets the frequency to the lowest (from the min, max frequencies). *Ondemand,sets the frequency according to the current usage. And the one we are interested in is: **Userspace, which allows the userspace program running with the id "root", to set the CPU to a specific frequency. (Van)

Up coming goals: Show you SOMETHING working Minnowboard running Possibly with batteries Control of CPU Frequency (With Hardware?) A driver for the Arduino (Just something basic) Arduino being a team player Communicate constants to the OS on boot Have some hardware display (7 Segment display acceptable)

Our up coming demo: We will have something to show for next time An ACPI Smart Battery Running with an ATTiny At least 1 chemistry Charge and Discharge Controlled by a master arduino

Our next presentation You tell us More Code? More Pictures? What do you want to know?