The SS39L Breadboard includes all parts required for 9 projects. These projects constitute an important subset of circuit design when recording and processing physiological signals. Students will be able to design sophisticated physiological amplification and processing circuits using a simple modular approach. Weekly labs can be oriented around a single "processing circuit module" - one per week - or a combination thereof. The final class project can be a complete system which employs all or some large fraction of the modules. This lesson details one possible suggestion for the final class project, an illustrated ECG R-wave detector.

• The component lessons are detailed in BSL PRO Lesson H25 Bioengineering Breadboard I.

Throughout the building and testing of these modules, the BSL PRO software, in conjunction with the MP30, can be used to supply isolated circuit power and perform signal measurements. Additional equipment, such as power supplies or oscilloscopes, are not required. One of the lessons does build a simple signal generator, however a separate signal generator is recommended to increase your options for testing and evaluating the lessons.

The graph below shows the output effect from the following circuits, with channels displayed in from the top down:

1. Active Filter: High Pass (HP .05Hz)
2. Active Filter: Low Pass (LP 100Hz)
3. Active Filter: Single Frequency Notch (60Hz Notch)
4. Active Filter: Single Frequency Band Pass (BP 17Hz Q=5)
5. Absolute Value Converter (ABS Value)
6. Logarithmic Amplifier (LP 10Hz)
7. Sine Wave Generator

  Instrumentation amp

This design, a classical 3 op-amp configuration, will permit recording of biopotentials such as ECG and EMG.

  Active Filter: High pass

High pass filters are required in all biopotential amplification designs in order to constrain the signals to frequencies of interest and to eliminate undesirable electrode offset potentials.

  Active Filter: Low pass

Low pass filters are required in all biopotential amplification designs in order to constrain the signals to frequencies of interest and to provide for anti-aliasing in anticipation of digitizing.

  Active Filter: Single Frequency Notch

Single Frequency Notch filters are often required in biopotential amplification designs in order to remove undesirable steady state interference such as 50 or 60 Hz signals associated with the mains.

  Active Filter: Single Frequency Band pass

Single Frequency Band pass filters are required in certain biopotential amplification designs in order to isolate frequencies indicative of certain wave shapes.

  Absolute Value Converter

An absolute value converter is often used when attempting to measure the amplitude or power of a bipolar signal. The absolute power circuit converter will typically be followed by a low pass filter to smooth the response, so signal amplitude can be estimated using a low sampling rate digitizer.

  Logarithmic Amplifier

A logarithmic amplifier is used for the purposes of signal compression.

  Sine Wave Generator

A sine wave generator has many uses, including impedance checking and physiological stimulation.