OK, So I don't have any code yet, but I'm wondering if it would be possible to "record" and analog signal from an inclinometer sensor that typically ranges from 3.5v to 4.7v or a 1v swing if that matters. I would like to record it and store the sampled digital representation as the angle changes for a period of 10 seconds. Then later I would like to replay it using an external DAC.
Yes, that is possible.
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Possible? Sure it's possible. When we collect data it's like any dataacquisition, we need someplace to put it and a format to store the data. There is no shortage of data acquisition systems including an Arduino using a shield. A Google of Adafruit Assembled Data Logging Shield for Arduino should get you a bunch of hits.
Your exact application will really determine the best choice in hardware.
There are turn key off the shelf solutions from Lab Jack and Dataq Instruments just to name a few which come with charting software off the shelf as well as creating for example CSV files if you want to dump the data into Excel or other spreadsheet software. Permanent setup or just a temporary test or similar?
Ron
Have used it here with superb results.
If you know how many samples per second you would require, that would help in deciding whether you can stream the samples to a PC data collection application or whether you need to store them locally and upload them at the end of the sample period.
Hmm.. I like the idea of the Adafruit data logger and it's pretty cheap too.. I need to record (log) analog data from two sources and inclinometer (3.5 - 4.7v) and a Load cell (0.5 mV - 15mV). If I were to guess sampling rate, I would say maybe 11KHz to 22KHz as I'm familiar with those in terms of recording audio.
Why?
Assuming you have a HX711 load cell chip, then a 10Hz sample rate could be enough.
No use sampling faster than your sensors can provide new data.
Leo..
See Jack Christensen’s Serial Data Logger project that writes to an SD card.
I'm actually getting the signal from the actual Load Cell which is basically a wheatstone bridge. It takes 5-8volts in and provides a small millivolt output which I typically measure between 0-15mV. There is no pre-amplification or A/D going on with this particular load cell. But you're right, I probably don't need a KHz sampling rate..
It's called the sensitivity of your load cell. You provide excitation across your bridge and yopu get an output proportional to the applied load and excitation voltage. This is normally called out as mV/V. For example I have a 100 Lb load cell with a sensitivity of 2 mV/V. With a full scale load applied of 100 Lb and 10 Volts excitation your Eout would be 20 mV. The Eout is a direct function of the excitation voltage.
To really do much with a plain bridge load cell you need a known stable excitation voltage and be able to amplify the bridge output. This is where using a HX711 works out well.
Ron
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