SHS3 Robotics · Semester 2 Week 12: Digital and Analogue System Design

Lesson notes

Learning Objectives

Indicator: 3.2.1.LI.1 - Observe the input/output pairs of combinational circuit black boxes and reverse-engineer the circuit.

By the end of the lesson, learners can:

Record and tabulate the input/output pairs of a given combinational circuit presented as a black box.
Deduce the Boolean expression of a combinational circuit from its observed truth table.
Construct a logic circuit diagram that matches the observed input/output behaviour.
Verify a reconstructed circuit on a breadboard against the original black box outputs.
Evaluate and document possible improvements to the reverse-engineered circuit with justification.

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Curriculum details

Strand: Robot Design Methodologies (Strand 2)
Sub-strand: Digital and Analogue System Design (2.1)
Content standard: 3.2.1.CS.1 - 3.2.1.CS.1 Demonstrate practical skills in the design and implementation of combinational digital systems that solve actual problems. 3.2.1.LO.1 Reverse engineer an existing combinational circuit and implement similar circuits or improved versions.
Indicator: 3.2.1.LI.1 - Observe the input/output pairs of combinational circuit black boxes and reverse-engineer the circuit.
Suggested placement: Semester 2, Week 12 (Week 32 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 162

Exemplars (from the NaCCA curriculum)

Project-Based Learning: Learners work in small mixed-ability/ gender groups to recreate existing combinational circuits. The following steps may be adopted:
- Collect information about the existing circuit. This could mean identifying and analysing source designs and schematics, monitoring input/output pairs with oscilloscopes, etc.
- Create partwise circuit designs where the circuit looks too complete.
- Where necessary, disassemble the circuit layer by layer and organise the parts in the order that they were taken off for easier reassembly.
- Analyse, measure and discuss the various parts to understand their function.
- Evaluate the disassembled components and take notes on how the circuit can be improved.
- Follow combinational circuit design principles to create a replica or improved version of the analysed circuit.

Assessment (3.2.1.AS.1). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning.

Teaching and Learning Resources:
- Oscilloscope, virtual laboratory with required software installed
- Flow charts
- Design narratives
- Online resources
- Pictures
- Circuit and breadboards
- Access to the lab with requisite tools (multimeters, soldering iron, glue guns, screwdrivers, etc.)