DAQ Input Collection

This week the MATLAB code was established for interfacing with the instrumentation amplifier. Since the legacy interface only works with 32-bit copies of MATLAB, we made use of the session-based interface which is compatible with both the 32- and 64-bit copies of MATLAB, although it can only utilize the analog inputs and outputs of the DAQ.

The code first determines what devices are currently connected to the machine, and upon locating them, it creates a session to interface with a given vendor ID. Then, it sets the sampling rate to 48,000 and time information. Next, it sets the number of samples to be obtained or the duration (in seconds) for which the code must run.

The data comes into the DAQ through one analog input by means of a referenced single-ended input (RSE), whose reference point is set by the electrode that will be placed on the subject. The code then adds the channel, sets the input range of the DAQ, and runs the session and plots the values obtained. Dividing the duration of the data collection by the number of scans will determine the spacing between each plot point, which is also equivalent to the inverse of the sampling rate, and can be used to generate the time values that correspond to the samples. By next week, the code will be configured to acquire raw surface EMG/EOG data.

 

Figure 11: DAQ used to collect input from subject