This is a super mini voltmeter with 0.28 inch LED display. It has reverse connect protection (though it is advisable to mind your wiring). When voltage is less than 10V, two decimal places will be shown. When voltage is more than 10V, one decimal place will be shown. This voltmeter would be great for a battery readout on your next robot, or generally useful for a retro readout panel!

The Grove - Hall Sensor measures the Hall Effect, which is a production of a voltage difference across an electrical conductor, transverse to an electric current in the conductor, as well as a magnetic field perpendicular to the current. The output of the continuous-time switch Hall sensor on this Twig switches low and turns on when a magnetic field (south polarity) perpendicular to the Hall sensor exceeds the BOP threshold, and it switches high (turns on) when the magnetic field disappears. ...

This is a standalone DC Voltmeter. It measures 3V-30V with ±1% accuracy. Best suited for battery level display. Just apply two wires on the power without any extra circuitry or components, it gives the reading straight away. Easy to use, and is a good companion to robotic applications.

The Voltage Sensor measures the differential voltage between the input terminals and outputs the difference proportionally. The maximum differential voltage that can be measured accurately is ±30V. Resources Product Manual   Product Specifications Characteristic Value Current Consumption 3.6mA Input Impedance 1MegaOhm Recommended Max Difference between Vin+ and Vin- 30V Absolute Maximum difference between Vin+ and Vin- 35V Input CMR 40V Output Range 0 to 5V Min/Max error ±2% Typical Error...

Measure AC & DC Current from -30 to +30 Amps. Includes 60cm sensor cable.  This sensor outputs 0-5V and is intended to be used with the Phidgets 8/8/8. This product is part of the Phidgets family! Phidgets are an easy to use set of USB-based building blocks for low cost sensing and control from your PC. A wide array of sensors, I/O devices, and controllers are available. To view the entire Phidgets product line, follow this link. Getting Started with Phidgets Phidgets Documentation:...