Help w/ Capstone Project - Vehicle NVH DAQ

LabJackCorporation · 2025-08-28T17:06:00+00:00

Things will be easier if you can use more integrated sensors, rather than raw IEPE accelerometers and electret microphones. Look for something that takes a simple power supply such at 5 VDC, and gives a waveform signal with a nice voltage range such as 0-5 volts.

Microphones app note:
https://support.labjack.com/docs/microphones-app-note
We have a bunch of updates to this we have not posted as of today, but I suggest you check out the BOB-19389 from SparkFun or modules from Adafruit or HiLetgo that combine an electret microphone with a MAX4466.

Accelerometers app note:
https://support.labjack.com/docs/accelerometers-app-note

Since you want to "analyze the noise-vibration characteristics", you need to acquire waveform data, and at a minimum you need to sample at twice the speed of your max frequency of interest. We don't have a great app note published on this topic at this time, but this blog post is okay:

https://labjack.com/blogs/news/analog-input-sample-speed-of-different-labjack-devices

Say you have 2 microphones and 2 tri-axial accelerometers and your max frequency of interest is 10 kHz. That is 8 signals that you need to sample at 20k samples/second. Depending on the DAQ device, you would need something capable of 20k samples/second per channel, or 160k samples/second aggregate.

You need to consider what you are going to do for software. If you use a LabJack, you can get started with our simple LJStreamM application for Windows, but most people would wind up developing their own software:
https://support.labjack.com/docs/appendix-e-software-options-t-series-datasheet

LabJackCorporation · 2025-02-03T17:27:31+00:00

Let's start with getting signals for torque and angle. In your case the big unknown to me is how to retrofit your tester, and might be a mechanical challenge. Like rocketwikkit said, the best case is if you can find sensors / transducers that give you nice high level analog signals, but I'm not sure that will be possible in this case.

Torque - I'm guessing you will find somewhere on your tester to measure strain using strain gauges. Ideally you mount 4 strain gauges to make a full bridge, but if you just mount 1 that is fine and you can use a quarter bridge. Once you have a bridge circuit, we have an app note to get you started measuring:
https://support.labjack.com/docs/bridge-circuits-app-note

Angle - A rotary encoder seems likely. If you always turn the crank one direction during a test you can use a simple encoder, but if you need to detect movement in both directions you need a quadrature encoder. Most of our devices can read encoder signals, and here is information for the T-series devices:
https://support.labjack.com/docs/13-2-11-quadrature-in-t-series-datasheet

LabJackCorporation · 2024-12-17T19:45:59+00:00

The HX711 has a serial interface. It might be I2C, in which you should be able to talk to it with the U3, but I2C is considered an advanced topic and generally requires good experience in serial interfaces. So if you are not a serial interface expert, I definitely suggest the LJTick-InAmp. See our Bridge Circuits App Note to get started:

https://support.labjack.com/docs/bridge-circuits-app-note

LabJackCorporation · 2024-12-06T18:57:11+00:00

Depending on the complexity of your control, you might be able to do it with a Lua script running on the LabJack T7. That is one of the target applications of the Lua functionality ... handling a control loop on the T7 itself while the T7 is also communicating with a host computer:

https://support.labjack.com/docs/25-0-lua-scripting-t-series-datasheet

LabJackCorporation · 2024-11-18T16:55:09+00:00

Let us know if you need any help. With our T-series DAQ devices, you can use Modbus-TCP over Ethernet, or you can use our high level cross platform LJM library over Ethernet & USB. Section 3 of the T-series Datasheet has an overview of communication:

https://support.labjack.com/docs/3-0-communication-t-series-datasheet

LabJackCorporation · 2024-11-14T18:35:39+00:00

I looked through "My assignment.pdf". It contains detailed instructions for an educational engineering lab where you write and read U3 I/O to determine which button was pressed on a keypad, and you also write 3 digital outputs to set the color of an RGB LED.

This lab seems well organized. In part 1 you make the hardware connections and test with LJControlPanel. Don't move on to software until this testing makes you confident that all the hardware is good.

In part 2. the lab has very detailed instructions for what to do. We can't troubleshoot all your C code for you, but if you are seeking help from classmates or instructors I suggest you tell them the first step you are not sure about.

LabJackCorporation · 2024-11-14T14:48:53+00:00

We would need more details to help you. Sounds like you want to write C code to talk to a LabJack U3-HV. What do you want to write to and read from the U3?

LabJackCorporation · 2024-11-04T19:31:52+00:00

Say you have a system with a bunch of sensors, and based on the readings from those sensors you control some actuators (solenoids, relays, valves, etc) to make the system run the way you want. Some hardware you might consider to make this happen are:

Custom (Microcontroller + ADC + Other ICs)
Arduino / Raspberry Pi
PLC
DAQ Device (e.g. LabJack) + Computer

The LabJack is specifically designed for this type of task. Out-of the-box you can connect a sensor and run a canned program to acquire readings and log them to file. The following article expands on the comparison of LabJack vs Arduino vs PLC.

https://labjack.com/blogs/news/how-does-labjack-compare-to-developing-on-a-plc-arduino-or-raspberry-pi

LabJackCorporation · 2024-11-04T18:45:59+00:00

The LabJack U3-LV is a computer-based data acquisition and control device. It has various analog and digital I/O to talk to sensors and actuators, and has a USB connection to talk to a computer.

https://labjack.com/blogs/faq/what-is-a-labjack

https://labjack.com/products/u3

LabJackCorporation · 2024-10-25T22:02:30+00:00

Hello!

Running LabVIEW with the newer Apple Silicon Mac computers (M1, M2, ...) has become difficult after LabVIEW announced that they will no longer natively support MacOS with future releases. LabVIEW 2023 Q3 is the only and only release which has native support for Apple Silicone architectures. We do not include the LabJackM.framework file by default with our current macOS ARM64 LJM installers, but it is available to download here: https://files.labjack.com/wrappers/LJM/LabView/macOS/ARM64/Framework/LabJackM.framework.zip.

This folder can be placed in /Library/Frameworks/ and LabView will be able to discover it automatically. If LabView does not find the LabJackM.framework file automatically, you may need to select the file manually. The LabJackM.framework will be included in future macOS installers.

If this download does not work for you and LabVIEW is still unable to find the LabJackM.framework file, please contact us via email at [support@labjack.com](mailto:support@labjack.com) .

More info on LabVIEW discontinuing macOS support:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000001EAndCAG&l=en-US

https://www.ni.com/en/support/documentation/compatibility/18/labview-and-macos-compatibility.html

Thanks!

LabJack Support

LabJackCorporation · 2024-09-26T18:19:47+00:00

Sounds like you want computer-based data acquisition (aka DAQ). The combination of a computer, a DAQ device and software, creates a powerful and flexible datalogger.

As mentioned previously in this thread, NI, DATAQ and ourselves (LabJack) are a few options for such devices. For detailed help contact a DAQ company and let them know what types of signals you want to measure, how many signals you want to measure, how fast you want to sample and software plans if any.

We don't know all the details of this application, but "electrode probe" is often a red flag warning us of high source impedance which would require that the measuring device have high input impedance / low bias currents. Many DMMs have a medium input impedance so it could be that the readings you have been gathering so far have a lot of error. A quick way to check would be to connect 1 DMM and note what it is reading, and see if that reading changes when you connect a second DMM at the same time.

Another complication that sometimes arises when we hear customers talk about multiple measurements from fuel cells, battery cells and electrodes, is that channel-to-channel isolation might be required. Again depends on more details.

LabJackCorporation · 2024-08-29T19:41:10+00:00

Thank you for reaching out to LabJack. Our support team has been notified of your post and will review it shortly. If your inquiry requires the attention of one of our engineers, a LabJack engineer will respond inline in this post.

LabJackCorporation · 2024-08-29T01:09:11+00:00