• Reprogrammable micro-controller, analogue output, TTL serial output for debugging / data logging & of course, open source.• Data is passed through transparently from end to end, so you can use it with any USB (Universal Serial Bus) device at any speed• The power line has a 0.1 ohm current sense resistor an an INA169 high-side current sensor that is tracked by a little ATtiny 85 chip• The microcontroller is programmed to read the current draw as well as the bus voltage & light up the strip of LEDs on the side• The blue LEDs will light up, one for each Watt of power draw (which is ~200m A at 5V nominal), with a couple levels of PWM dimming for increasing current• You can measure up to 1A of current draw
- most USB (Universal Serial Bus) ports are rated for 500m A• It's safe to use this with something that draws up to 2 A of current, it'll just 'max out' the LEDs• The green LED is helpful to tell if you have too much droop on your power line• It stays lit as long as the voltage is higher than 4.5V, most devices won't charge effectively once it goes below that so if the green LED goes out, you know you should check your port, shorten the USB (Universal Serial Bus) cable, or reduce the current draw• It also prints out the voltage, current & wattage data as readable text on the TX pin at 9600 baud. Connect an FTDI friend, USB (Universal Serial Bus) console cable, microcontroller, XBee, whatever you want that can read 9600 baud TTL serial data for data logging, plotting or display• Please Click here to find the source code & schematic This little USB (Universal Serial Bus) port go-between is like a speed gauge for your USB (Universal Serial Bus) devices. Instead of hauling out a multimeter & splicing cables, plug this in between for a quick reading on how much current is being drawn from the port. Great for seeing the charge rate of your phone or tablet, checking your battery chargers, or other USB (Universal Serial Bus) powered projects. Comes as a mini kit with an assembled & tested PCB plus a separate USB (Universal Serial Bus) jack & plug as shown above. Before use, solder the jack & plug. It'll only take you a few minutes & can be done with any soldering iron. Or, advanced users can splice it between a USB (Universal Serial Bus) extension cable. Please note: this is a handy gadget but it isn't a multimeter! We do some basic calibration during test, but the serial output readings are not precise & should be used as a basic guide rather than lab-grade data plots. Assume a variance of at least 0.1V & 50m A due to noise, thermal changes, etc.