1. M3 Overall Project Objective: To design a chip for a SCUBA diver that does real-time calculations to warn the diver of safety concerns including decompressions sickness and lung overexpansion. Stage : 21 Jan 04 Proposal Outline ProDiver 525 Kavita Arora (M3-1) Lisa Gentry (M3-2) Steven Wasik (M3-3) *Karolina Werner (M3-4) Design Manager: Steven Beigelmacher

2. M3: ProDiver 525 Status Specification definition (done) Specification definition (done) Matlab Simulation – Simulink (done for most modules) Matlab Simulation – Simulink (done for most modules) Verilog (just starting) Verilog (just starting) Still have a long way to go… Still have a long way to go…

3. M3: ProDiver 525 Background: Scuba Tables SCUBA = Self Contained Underwater Breathing Apparatus SCUBA = Self Contained Underwater Breathing Apparatus Generally considered safe, as long as one follows certain parameters Generally considered safe, as long as one follows certain parameters Every 33 feet down, the air compresses one atmosphere (pressure increases) Every 33 feet down, the air compresses one atmosphere (pressure increases) Nitrogen intake also increases and becomes dangerous at certain levels Nitrogen intake also increases and becomes dangerous at certain levels Can cause Decompression Sickness, also known as “the bends” Can cause Decompression Sickness, also known as “the bends” Proper use of tables tells the diver how long he or she can safely stay at certain depths Proper use of tables tells the diver how long he or she can safely stay at certain depths

4. M3: ProDiver 525 SCUBA Computer Many divers have difficulty with the tables Many divers have difficulty with the tables A computer can go underwater and get more accurate data, thus allowing for less conservative values (can safely stay underwater longer) A computer can go underwater and get more accurate data, thus allowing for less conservative values (can safely stay underwater longer) Other features can also help to keep the diver safe Other features can also help to keep the diver safe

5. M3: ProDiver 525 Our Computer Customized to body type / dive circumstances Customized to body type / dive circumstances Real-time calculations of the internal body pressure (and thus nitrogen level) and output if a safety or decompression stop is needed Real-time calculations of the internal body pressure (and thus nitrogen level) and output if a safety or decompression stop is needed Watches ascension rate to prevent lung overexpansion Watches ascension rate to prevent lung overexpansion Keeps track of statistics for the diver’s log book (bottom time, max depth) Keeps track of statistics for the diver’s log book (bottom time, max depth) Time to flight Time to flight How long can I safely stay at this depth? How long can I safely stay at this depth?

6. M3: ProDiver 525 The Math The level of nitrogen absorption is proportional to the difference between the body’s internal pressure and the external pressure The level of nitrogen absorption is proportional to the difference between the body’s internal pressure and the external pressure dP t (t)/dt = k*(P(t)-P t (t)) dP t (t)/dt = k*(P(t)-P t (t)) Can be modeled as a difference equation Can be modeled as a difference equation –P t (t) = P t (t-1) + k*(P(i)- P t (t-1)) Takes in a depth value (feet) every second Takes in a depth value (feet) every second Nitrogen level is OK until the body’s tissue pressure reaches 33 feet Nitrogen level is OK until the body’s tissue pressure reaches 33 feet

7. M3: ProDiver 525 Design Model

8. M3: ProDiver 525 Design Decisions We decided to go with solving the differential equation rather than lookup tables We decided to go with solving the differential equation rather than lookup tables –More accurate readings Real Time Data Real Time Data –Depth reading every second –Immediate results Divided the project up into 6 modules Divided the project up into 6 modules

9. M3: ProDiver 525 Transistor Estimates Get K = ~200 Get K = ~200 Pressure Calculator = ~4000 Pressure Calculator = ~4000 Ascension Watcher = ~400 Ascension Watcher = ~400 Time to Flight = ~3000 Time to Flight = ~3000 2 Get Max = 600 * 2 = ~1200 2 Get Max = 600 * 2 = ~1200 Time Left = ~4000? Time Left = ~4000? Overhead Control Logic = ~400 Overhead Control Logic = ~400 TOTAL = ~13200 TOTAL = ~13200