Overview

This tool enables the readout of drawn power and supplied power from Corsair RMi-series power supplies in a stopwatch-like fashion, using the OpenCorsairLink project as a driver for the USB interface. The sampling rate is configurable, and results can be either stored in memory, or written directly to a file.

Prerequisties

• libusb-1.0 (available through all major package managers)

Building and installing

Make sure to clone with --recursive, or pull submodules with git submodule update --init to fetch the OpenCorsairLink dependency.

The project uses a standard CMake setup:

mkdir build
cd build
cmake .. -DCMAKE_INSTALL_PREFIX=<installation directory>
make install

This will install the required header files, along with the libpowermeter static library.

To use the tool within an existing project, either use the provided CMake configuration, or simply include <installation directory>/include/powermeter and link to <installation directory>/lib/libpowermeter.a.

Usage

See examples/Example.cpp for example usage.

Note that all executables must be run with sudo privileges to interact with the USB interface.

The PowerMeter class provides stopwatch-like functionality for measuring power:

PowerMeter pm(50);          // Records samples at an interval of 50 milliseconds
pm.Start();                 // Start sampling
// ...do interesting work...
pm.Stop();                  // Stop sampling
auto res = pm.PopSamples(); // Returns a vector<std::tuple<Time_t, double, double>>, where each entry
                            // contains the timestamp, drawn power, and supplied power, and Time_t is
                            // the type std::chrono::high_resolution_clock::time_point

As an optional second argument, PowerMeter takes an std::ostream where input will be written instead of storing it internally. This can be used to write results directly to a file:

std::ofstream out_file("power_measurements.csv", "w");
PowerMeter pm(50, out_file);
pm.Start();
// ...do interesting work...
pm.Stop(); // Results will be present in power_measurements.csv

Or, directly to standard output:

PowerMeter pm(50, std::cout); // Samples are written directly to the terminal/standard out

The timestamps are returned as std::chrono::high_resolution_clock::time_point, and can be converted to microseconds since epoch by using:

sample.time_since_epoch().count()

Running

The included example executable prints power measurements to standard output for a given time, with a given interval:

sudo ./Example 5 50

This will print samples every 50 milliseconds for 5 seconds.

Bugs and suggestions

Please direct bugs and suggestions for improvements to the issue tracker.