Interactive Breadboard Spring 2013 Group 21 - Simon Huynh, Norman Lee, Harrison Hilgers TA Dennis Yuan, Professor Carney

Introduction Breadboarding was a steep and difficult learning curve in ECE 385 We thought there could be an easy and fun way to learn breadboarding circuits The Interactive Breadboard is an oversized breadboard that will step students through some basic labs with the ability to detect errors in each step along the way This tool, complete with its own lab manual and programmable labs, will be able to teach circuitry to kids even in high school

Overview and Modules

Power Supply Schematic

Power Supply Rectifier Simulation

Power Supply Verifications - Supply constant voltage with varying current (maximum) amps Short Circuit!

Power Supply Verifications - Short circuit power supply without damaging components Short Circuit!

Power Supply Verifications - Operate at high amperage (3.33Ω load) for 60 seconds without reducing current

Breadboard Made from large array of female banana sockets space 1/2" appart (1" down the center) 80 nodes (40 rows) + power & ground node along side Checked continuity and discontinuity between each node

Breadboard Enclosure Model Drew autocad sketches and made cardboard model Machine shop used models to build enclosure from acrylic sheets

Breadboard Enclosure IO panel and breadboard unscrewed from base to allow access to internal wiring IO panel was never completed

Chip Enclosures Made our own chip enclosures Tested each one on the breadboard to ensure functionality of each chip Pins were not very precise

Switches and LEDs PCB Four PCBs total Switches used pull-down resistors Switch outputs and LED inputs down center of the board

Switches and LEDs Verified each LED and switch worked with multimeter Problem: Getting all switches to trigger when inserting chip. Solution: Foam Machine shop made standoff mounts

Lab Manual Labs included: o Basic gate functionality (NOT, AND, OR, NOR, NAND, XOR) o Creating larger AND/OR gates o Full Adder o Multiplexer/Demultiplexer o Comparator Included an introduction to binary numbers, how digital circuitry works, and binary addition Teaches user how to use the board

Prober Hardware Overview

Chip Location Detection

CLD Probe Design

SN74LS166SH/LD_NOTCLK INHCLKCLR_NOT Shift ModeHLRisingH Load ModeLLRisingH HoldxHxH ClearxxxL

CLD Probe Design

CLD Probe Requirements & Verifications Continuity on the board and between the boards is correct Shift register functionality (SN74LS166)

LED Shift Register

LED Shift Register Design

LED Shift Register Requirements & Verification Continuity on the board and between the boards is correct Shift register functionality (SN74LS164)

Chip Type Detection Probe

CTD Probe Design

74F675 CS_NOT (CLK INHIB) R/W_NOT SHCP_NOT (CLK_NOT) STCP (SH_NOT/LD) Shift ModeLHFallingL Load ModeLHXRising HoldHXXH SN74LS166SH/LD_NOTCLK INHCLKCLR_NOT Shift ModeHLRisingH Load ModeLLRisingH HoldXHXH ClearXXXL

CTD Probe Design Vector Board Used Five 16-bit identical modules IC Chip mounts used for easy debugging and soldering

CTD Probe Design

CTD Probe Requirements & Verification Continuity on the board and between the boards is correct Shift register functionality (SN74LS166 / 74F675/ 74HC125)

Control Unit Brains of the Interactive Breadboard o Drives the logic that tells what kind of signals to send o Internal data structures that track different information from the breadboard

State Machine

Load/Update Design Tells registers to load data then shift int g_CLDCurrent[80] and g_CLDResult[80] o Holds CLD data, 0 for empty, 1 for occupied o Current is the saved data on the board, result is the data read in from registers int g_LEDBoard[80] o 1 is on, 0 is off o Uses g_CLDCurrent and g_ChipBoard to determine

Check Lab/Load Next Probe potential chips and classify them in g_chipBoard[80] o Probe by sending electrical sign o 0 is empty, 1 is unknown, 2-8 are AND, OR, etc. Checks to see if any of the chips or wires are in the lists RequiredWires/RequiredChips If we have everything we need, load next Lab steps were preprogrammed in, due to time constraints

Wires defstruct Gate Input1 Input2 Name ex. -NAND IN1 Vcc n_nand1 -OR n_nand1 IN2 n_or1 Toss all acceptable variable names into a list.

Control Unit Requirements Clock toggles can switch on/off within 5 microseconds Arduino can write out HIGH/LOW at 5v/0v with tolerance ±1v Arduino can read in HIGH/LOW at 5v/0v with tolerance ±1v Ensure state machine turns on the correct control pins while in the proper states Ensure state machine moves onto the proper next state

Control Unit Verifications Clock Verifications

Control Unit Verifications Arduino Read/Write

Control Unit Verifications Arduino State Machine control pin outputs

Control Unit Verifications State machine control flow

If we were to do it again.... Better communication between team members so PCB integration is better Use ribbon cables or pin headers to connect the PCBs Reduce wasted space on PCBs Have machine shop build the chip enclosures