USB Tachometer Interface

Faced with yet another instance of "Why can't we find a good existing solution for _______?" RechargeCar Inc. took it upon ourselves (we apparently speak in the Corporate Third Person perspective) to develop a series of hardened sensor interfaces, such as this USB tachometer, that make computer interpretation of commonly desired data as easy and flexible as any USB-equipped modern World citizen could want. Introducing AutoBlocks!

AutoBlocks receive the signals from common sensors, package them up neatly into our open, computer readable output, and spew it through your trusty USB ports.

The AutoBlock RPM is connected to your computer with a standard USB cable. With our easy to use, highly customizable and free software, you will be able to see exactly what is going on with your system, troubleshoot, optimize, design, whatever.


A basic setup of the AutoBlock RPM is shown here. A rotational sensor (Hall effect, magnetic pickup, our Warp™ Speed Sensor kit, etc) is mounted to a typical EV motor and wired to our sensor wire harness. The harness plugs directly into the AutoBlock RPM. The AutoBlock RPM is connected via a supplied USB cable to a laptop or installed "carputer".

That's it, your computer is ready to display and record how fast the motor is turning.

There are many other applications for our AutoBlocks, we will leave that up to you to explore the possibilities.


Our easy-to-use, highly customizable software will allow you to quickly get up and running. Simply plug in the AutoBlock into your computer, launch our software, and off you go.

Our software can also record the RPM of the device you are measuring for later use. Click here to download our inititial release.

We will also publish the communication protocol (USB packet structure) for this and future AutoBlocks, opening up many options for EV metrics display and management. Learn more about our OpenAPI EV Management Initiative


Our AutoBlock is designed to be durable, easy to install and use. Each AutoBlock comes with 2 mounting brackets for easy installation. They may be adjusted or removed depending on your application. The mounting brackets slide easily into the slots on either side of the durable anodized, watertight aluminum enclosure. The beautiful red enclosure features laser-etched labels and is assembled with the highest quality, stainless steel hardware.

Each connector was designed to provide a water-tight, robust interface to the outside world.


In order to simplify installation and trouble-shooting, we decided to include a few important features. Our indicator LEDs show the status of data transportation and quality. We designed a simple, but effective USB cable lock compatible with standard USB cables, and providing protection water and dirt, and other nastiness under the hood.

  1. USB cable lock - In order to secure your USB cable and keep it firmly seated into the weather-proof connection, simply tighten this set-screw. We include the Allen wrench to tighten this and the mounting brackets with the AutoBlock.
  2. USB cable - we provide a high-quality USB cable. This is how information gets from the AutoBlock RPM to your computer.
  3. Power LED - illuminates Green when the AutoBlock is receiving power.
  4. Data LED - flashes Yellow when good data is sent from the AutoBlock RPM to your computer.

  1. Input LED - this LED flashes when the AutoBlock is receiving good data from the sensor. For example, when the target of a magnetic pickup passes by.

  2. Sensor wire harness - we provide a high quality 8' sensor wireharness. One end is pre-wired with a water-proof connector, while the other is pre-stripped and tinned; ready to connect to your sensor. This harness consists of 4 wires with the following pin-out:

  3. GND (Black) - Ground for sensor
    SIG (Green) - signal from sensor
    12Vo (Red) - 12 volts OUT, current limited (to power some sensors)
    5Vo (White) - 5 volts OUT, current limited (to power some sensors)


We designed our AutoBlock RPM to be compatible with as many sensors as possible. The internal circuitry simply monitors the periodic waveform created by a sensor and extrapolates the period between peaks. As long as your sensor provides a periodic waveform (proportional to whatever is rotating) you are good to go. The software handles the math to calculate actual RPM.

You can connect to an existing sensor in your car, or install a new one. Since some sensors require power, we provide either 5 or 12 volts on our sensor harness.

If you use a WarP™ Motor, we offer a bolt-on and plug-in solution: Warp™ Speed Sensor


AutoBlock RPM is now available. The lead time for shipment of this product is currently 3 to 5 business days.