OpenCVMeter - Rediscover Your Capacitors !
An open source tool to measure capacitance and leakage current as a function of a capacitor's working voltage.
All Capacitors Aren't Created Equal
When designing circuits, many hobbyists take capacitors for granted - but each type (ceramic multi-layer, aluminum electrolytic, tantalum, mica...) has its own unique properties. Nowadays, ceramic capacitors are the most commonly used capacitors in the industry, but many can lose up to 80% of their rated capacitance near their voltage ratings.
Enter the OpenCVMeter! This meter aims to provide a Capacitance versus Voltage characterization accurate within 1% of the capacitors for your next project (or already have and are starting to wonder about right now...)
An Important Tool for Engineers and Hobbyists
There are many scenarios where capacitance is critical to the correct functioning of the circuit:
- Analog RC filters (signal processing, audio applications)
- DC/DC power supply design
- Decoupling applications
In some cases, a lower than specified capacitance may lead to sporadic hardware bugs, or in the extreme, a non-working device. The OpenCVMeter will give you the information you need to ensure this doesn't happen in your next prototype !
OK... What Else Can it Do?
The OpenCVMeter can also measure currents up to 12.4uA with a resolution of 6nA, which can be extremely useful when designing ultra low power devices.
For example, you could use the OpenCVMeter to verify that all your passive components (TVS diodes, electrolytic capacitors...) adhere to their leakage specifications - and ensure your device has maximum battery life.
Open Source Hardware AND O/S Independent
The OpenCVMeter doesn't need any drivers and works right out of the box with your Windows, Linux or Mac computer. You will be able to:
- Set the maximum voltage when characterizing capacitance or leakage current
- Specify the number of points for the generated curve
- Save the curve data points to a CSV file
- Use the OpenCVMeter as a standard capacitance meter
- Measure extremely low currents with a 6nA resolution
- Easily upgrade your OpenCVMeter's firmware
For the past few months, several beta testers have been using our application. Their feedback ensured that the software provides maximum functionality and works as intended. This application is simply installed via the Chrome App Store.
Made From Anodized Machined Aluminum
The OpenCVMeter case is made from grey anodized machined aluminum, giving it a nice professional look. The above picture is a prototype of the final design. The final design will incorporate a silkscreen logo with polarity markings.
The OpenCVMeter has two standard banana sockets, so you can hook it up any way you like. For good measure, it will be shipped with the following accessories to get you started:
- SMD tweezers, for all your SMD components
- Test hook cables, for all your through-hole components
- A current calibration kit composed of three resistors
Our Commitment to Open Source
All of our source code is already available for download in our official GitHub repository. The hardware files will be added to the repository once the campaign is complete.
So you want to know the nitty-gritty? Here are the advanced technical specifications of the OpenCVMeter:
- Generated voltage: 1.3V to 15.5V, ±2%
- Generated voltage accuracy: ±0.45% ±12mV
- Capacitance measurement accuracy: typ. 1%
- Capacitance measurement range (to be improved): 1pF to 200uF
- Current measurement range: 40nA to 12.4uA
- Current measurement resolution: 6nA
- Current measurement accuracy (calibrated): typ 1.5%
- Current calibration procedure time (to be improved): ~4 hours
Risks and challenges
I have already briefed the hardware assembler (whom I've worked with for the past 4 years on a variety of projects) in preparation for a mass production run. Two OpenCVMeter prototype batches have already been produced, and I am confident that the assembly process will go smoothly.
Of course, there's always the possibility that something might upset our schedule, but rest assured that I'll do our best to get your hardware delivered on-time and keep you informed every step of the way!Learn about accountability on Kickstarter
- (33 days)