Sprinkler Buddy

Presentation #3:

“System Level View and

Floor Plan / Sizing”

2/07/2007

Team M3Kartik Murthy

Kalyan KommineniPanchalam Ramanujan

Sasidhar Uppuluri Design Manager: Bowei Gai

“Low Cost Irrigation Management For Everyone ”

Current Status Determine Project Develop Project Specifications (refined)

Plan Architectural Design (refined)

Determination of all components in design Detailed logical flowchart

Design a Floor Plan Create Structural Verilog (Main modules done, working on control)

Make Gate Level Design and Schematic Layout Testing (Extraction, LVS, and Analog Sim.)

A Large and Untapped Market

95 % of the world’s 1.1 billion farmers live in developing nations

These farmers are being forced to manually water their crops due to expensive automation solutions

Current Solutions:Expensive and Un-

Automated Moving towards Drip Irrigation These systems cost from $5 for the most primitive

to $600 for larger farms

Sprinkler Buddy: The Low Cost, Automated

Solution!

Computation of Water Output Equation

Crop Water Need / Day = KC x ETO KC = Crop factor (from look up table)

Look up based on type and stage of crop ETO = (P)(0.46Tmean + 8)

P = Mean Daily % of Daylight Hours (from table) T mean = (T max + T min) / 2 T max = sum of previous 32 days of T max / 32 T min = sum of previous 32 days of T min / 32

53 Inputs and 2 Outputs

Inputs: Max/Min Temperature in degrees Celsius (10 bits ea.) Number representation of crop type (5 bits) Number representation of crop stage (2 bits) Month (4 bits) Water Tank Level (10 bits) Water at Plant (10 bits) Custom System Clock ( 2 bits )

Outputs : Control signal for the electric valve (1 bit) Flag which sets if a water shortage is seen (1 bit)

Architectural Changes Three stages

1st : Loading of new daily temperatures 2nd : Computation of equation 3rd : Water Management Mode (New !)

Daily Update ComputationInputs Water Management

Water Management Mode

Two Main Functions: Hourly Update of Temps Error Code Check and Valve Control Note: Rest of Circuit is OFF during this time!

+/-

Water In Tank

Water to be Output

Water Gauge Reading

2:1 Mux

Error Code&

Valve Control

2:1 Mux

+/-

T Max Reg T Min Reg

Write To Corresponding Register if Necessary

TEMP

Transistor Count …Block (# used) Transistor Count

40:20 Muxes (6) ~480

60:20 Muxes (2) ~720

Counter (2) ~250

KC ROM (1) ~778

P ROM (1) ~82

Metric Storage SRAMS (2) ~2522

Constant Storage ROM (1) ~202

Floating Point Adder (4) ~3000

Floating Point Multiplier (2) ~2800

10 Bit Registers (9) ~140

Datapath Logic / Misc. ~2000

Total =

~ 31,786

Block SizeBlock (# used) Size Estimate (um)

40:20 Muxes (4) 20 x 80

60:20 Muxes (2) 20 x 120

Counter (2) 12 x 17

KC ROM (4 parts) 181 x 8

P ROM (1) 70 x 8

Metric Storage SRAMS (2) 181 x 60

Constant Storage ROM (1) 181 x 8

Floating Point Adder (4) 100 x 100

Floating Point Multiplier (2) 130 x 130

10 Bit Registers (8) 50 x 10

Floor Plan Floor Plan

To Mux

Feedback from Mult

Routing into 40:20 Mux

From Mux/RomsOFF !(during most of the day)

Design SizeBlock (# used) Size Estimate (um)

40:20 Muxes (4) 20 x 80

60:20 Muxes (2) 20 x 120

Counter (2) 12 x 17

KC ROM (4 parts) 181 x 8

P ROM (1) 70 x 8

Metric Storage SRAMS (2)

181 x 60

Constant Storage ROM (1)

181 x 8

Floating Point Adder (4)

100 x 100

Floating Point Multiplier (2)

130 x 130

10 Bit Registers (8) 50 x 10

• 388um x 559 um• 1 : 1.44 aspect ratio• .2 mm^2 area• .142 Transistor Density

Metal Directionality M1, M2

Local Connections Ground and VDD

M3,M4 Clock Global Routing Control Signals

Design Challenges and Implementation

Decisions

Design Challenge Translation to HW

Low Power Design • Reuse Components• Low Power SRAM• Shut-off parts of Circuit

Ease of Use • Error Checking• Minimal Intuitive Inputs

Restrictions of Sensors

• 2’s complement to floating point

Verilog

Problems/QuestionsOur transistor count is highWe are somewhat close to the 2:1

aspect ratio limitAre we being too naïve in the amount of

area we are leaving for routing?Need to finalize the control logic to “turn

off” the computation part of the circuit…

For Next WeekWork on gate level conversion Create Initial SchematicContinue to update/revise floor plan as

needed

References Food and Agriculture Organization of the UN U.S. Department of Agriculture World Water Summit 2006 “Drip Irrigation for Small Farmers: A New

Initiative to Alleviate Hunger and Poverty” by Postel et. al.

Drip Irrigation Picture : http://www.actwithgenius.org/images/Bucket-kit-diagram-print.gif

OTHER SLIDES (just in case…)

Daily Update Mode

Initially load both temperatures w/min going to a register

T Max T Min10

T Min Reg

10

+/-

Sum of T Max Sum of T Min

Mux

Using a mux, pick the T Max input to the adderand add it to the previous sum of T Maxes

T MaxSRAM

T MinSRAM

Counter B

1

Counter A

1

Oldest Value Oldest Value

2:1 Mux

Go into the T Max SRAM and take out the oldest value andreplace it with the newest value.

Increment the corresponding counter to point to next oldest

Take the oldest value obtained, feed it back to the add/sub mux Subtract it from the sum previously computed

Take Tmax’s sum and the correct weight, multiply them, and store the result as the new average of Tmax

2:1 Mux

2:1 Mux

1->1/32

XT Max Avg T Min Avg

Repeat All Steps with Tmin!

Computation Mode

Take the averages from the daily update mode and average them

T Max Avg T Min Avg

+

2:1 Mux

/2 /2

3:1 Mux

X

.46

Multiply the result by .46

8

Add 8 to the resultP

ROM

Multiply with P from anSRAM lookup

KCROM

Multiply this with the KC From SRAM lookup

OUT

The Result is now ready!