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"A handy power-monitoring platform that lets you monitor power consumption that replaces up to four multimeters, all within a tiny footprint (66mm x 18.2mm x 18.5mm)."
"Utilizable en proyectos basados en Arduino Nano, este escudo para monitorización de potencia no es intrusivo, y dispone de una pantalla para ver los valores de alimentación o para utilizarse por la misma aplicación."
PowMeter was designed specifically to monitor power consumption of projects that use an Arduino Nano. Here's what sets it apart:
Unlike normal USB power monitoring dongles, PowMeter can simultaneously monitor the power supplied to your Arduino both over USB and the Arduino's VIN pin.
PowMeter has an onboard OLED screen for displaying real-time power usage over USB or VIN or both. This makes it a quick and noninvasive way to see what's going on with your project.
PowMeter is versatile enough to serve as a power supervisor that lets your program know when the voltage and/or current are outside of nominal ranges you define.
PowMeter fits under the already very tiny Nano board, adding only ten grams of weight and 26 mm of length where the display peeks out. This makes PowMeter ideal for fitting into tight spaces.
|A. USB power source||G. OLED 64 x 32. I2C address: 0x03|
|B. USB TP / auxillary input¹||H. VIN alert TP|
|C. USB current sense resistor and IC, I2C address: 0x42||I. VIN MON pin³|
|D. MBR0520 schottky||J. VIN current sense resistor and IC. I2C address: 0x40|
|E. VAUX pin²||K. MCU I2C address: 0x25|
|F. VIN MON - VIN jumper||L. USB alert TP|
¹ To power the USB rail from an auxiliary power source.
² VIN monitoring can include auxiliary peripheral power consumption connected to the added VAUX pin.
³ To monitor VIN power source connected to the added VIN MON pin.
High side or low side measurement: when used as a Nano Shield, measurement is on the high side.
By design, USB is a low power source. It is limited to 500 mA in regular Arduino applications. PowMeter uses a high performance current sense resistor of 100 mOhm in combination with the INA226 to get a resolution of only 0.025 mA on this channel. It could also be used to monitor any other power source up to 24 V with high resolution.
On the other hand, the VIN power source is normally used for power demanding applications. Often a 12 V source will power the peripherals (motors, etc.). On this channel a high performance, 10 mOhm current sense resistor allows measurement of currents up to 8 amps with a resolution of 0.25 mA.
Four display layouts: both, only USB, only VIN and Alert. Power source voltage (in Volts) is displayed above current (in milliamperes).
Alerts displays the alert source ("USB V", "USB C", "VIN V", "VIN C") and the measured value that is outside the programmed boundaries.
Underneath picture shows the monitoring of both USB power and peripherals. USB voltage is 5.10 Volts and USB consumption is 4.11 mA. VIN MON is connected to a 12 V power source and the peripherals are connected to VAUX. They are drawing 1157 mA (and pulling down the voltage to 11.8 V).
|Pandauino PowMeter||Adafruit USB Voltage Meter with OLED Display||X-DRAGON Dual USB Digital Meter|
|Form-factor||Arduino Nano shield||USB dongle with case||USB dongle with case|
|Main use||Project integration||Charging devices||Charging devices|
|Vin min voltage||0 V||n/a||n/a|
|Vin max voltage||24 V||n/a||n/a|
|Vin max current||8 A||n/a||n/a|
|Vin current resolution||0.25 mA||n/a||n/a|
|Vin voltage resolution||10 mV||n/a||n/a|
|USB min voltage||0 V||3.7 V||3.2 V|
|USB max voltage||24 V||13 V||15 V|
|USB max current||0.5 A modifiable to 0.8 A or more||3 A||3 A|
|USB current resolution||0.025 mA||10 mA||10 mA|
|USB voltage resolution||10 mV||10 mV||10 mV|
|Display layout||Voltage and current by default, user editable||Fixed: voltage, current, power, charge||Fixed: voltage and current|
|Auxiliary output powered from VIN (0-24 V)||Yes||No||No|
|Open source||Hardware & software||No||No|
|I2C configuration interface||Yes||No||No|
|In-project voltage and current measurement||Yes||No||No|
|OLED available for project use||Yes||No||No|
|Visual alert mode||Yes||No||Yes|
¹120 ms, 250 ms, 500 ms, 1 s, 2 s, 4 s, 8 s
A special data cable is included in the package. It has:
This will allow you to program your board and monitor its power consumption at the same time. It can also serve anytime you would like to program an Arduino board but power it from a source other than USB.
PCBs will be high quality (2 oz copper), fabricated by one of the specialized Chinese companies everyone knows about.
Sourcing will be from major distributors like Digi-key and also other distributors I already ordered from for specific parts like the OLED I2C display module.
In the context of this prototyping project, depending on the number of backers I would either:
There are a couple of options for assembly both in China, Spain and France.
Crowd Supply will handle all delivery except for the European Union. I will ship to all EU destinations. USA orders will be free of charge. All international (non-US) will be charged $7.
More details are provided on this useful page about ordering, paying, and shipping.
Sourcing components might be problematic.
Lately I have seen a couple of retailers run out of INA stock. Also I got some fake, non-working parts. The issue seems to be resolved as of mid November 2018. This is a classic part so I don't oversee a long lasting sourcing problem.
The 0.49" OLED I2C module might be difficult to get but there are a couple of retailers proposing it.
I also had problems with some Atmega chip, which were functional but mis-labelled. I will source this part only from a major distributor.
Since I am in France, proposing this shield on Crowd Supply (Portland USA) and sourcing from USA, China and possibly other countries there are shipping costs and delays that might impact the delivery. I focused on a relatively simple project at first for this reason and hope to deliver within a two month period.
You will be provided with a GitHub repository containing:
If you have a question about ordering, paying, or shipping, please refer to The Crowd Supply Guide.