1. 11 Wireless Sensor Networks (WSN) CPU Group Progress Presentation Almir Davis Yong Zhang Halligan Hall 03/17/2005

2. 22 Agenda  Sensor Card Diagram  Choosing Power Supply  CPU Design Progress  CPU New Features  Questions from the Proposal Presentation  Current Questions

3. 33 WSN Block Diagram

4. 44 Sensor Card

5. 55 Types of Chemical Weapons  Nerve Agents –Nerve agents attack the bodies nervous system. Nerve agents causse breathing difficulties, convulsions, paralysis, and death. Nerve agents can be inhaled or absorbed through the skin. Symptoms of nerve agent poisoning include runny nose, tightness of chest, difficulty breathing, excessive sweating, nausea, vomiting dimness of vision, pinpointing of the pupils, convulsion, and death.  Blister Agents –Blister agents attack the lungs, eyes, and skin. They blister both skin and mucous membranes.  Blood Agents –Blood agents interfere with the bodies ability to absorb oxygen. The victim dies because the body tissues are starved of oxygen. Blood agents cause headaches, vertigo, and nausea before death.  Choking Agents –Choking agents attack the lungs, causing them to fill with fluid. Choking agents are detected by their smell and their irritancy. The victim suffocates by drowning in his own body fluid. Choking agents cause coughing, choking, tightness of the chest, nasea, headache, and watering of the eyes.

6. 66 Common Chemical Weapons

7. 77 Choosing power supplies  AA Batteries –Capacity: 650mAh ~ 3135mAh  Button Cells –Capacity: 45mAh ~ 500mAh

8. 88 AA Batteries  Alkaline AA batteries –most common AA battery type. –Pre-charged to 1.5 Volt. –Unsteady voltage. –Capacity: 2,700 to 3,135 mAh. Most AA Alkaline cells offer a capacity of 2,850 mAh. The expensive Energizer e2 alkaline offer 3,135 mAh and the cheapest cells offer 2,700 mAh, all pretty much alike at low drains. (That's why Consumer Report's testing suggested to get whatever's cheapest). –Shelf life: some current premium brands exceed 6 years.

9. 99 AA Batteries  Lithium AA batteries –Premium AA battery type. –Pre-charged to 1.5 Volt. –Constant 1.5 Volt over their life. –Capacity: premium brand Lithium AA cells offer around 3,000 mAh, the same as Alkaline. –Shelf life up to ten years, and a longer lifetime than an alkaline battery. Also retain much better capacity in low temperature (less than 25 °C) than alkaline batteries –Disadvantage: expensive compared to Alkaline.

10. 10  Rechargeable AA batteries –Ni-Cd, Nickel-Cadmium: Capacity: 650 to 1,000 mAh –Ni-MH, Nickel-Metal Hydride: Capacity: 1,350 to 2,500 mAh AA Batteries

11. 11 Low Battery Warning Circuit  What would be required is a circuit that constantly monitors the battery voltage, and if it reaches a magic low- point, it gives a signal to CPU. Then the CPU will command the transceiver to send a low battery warning to the base station.  Such a circuit would have to be micro- powered; that is, it draws next to nothing from the battery itself, so it may be left in the circuit continuously without adversely affecting battery reserve.

12. 12 CPU Block Diagram

13. 13 CPU Features  Cut-through data path  Aggregation of Sensors’ packets  Selection of Sensors’ packets  “Sleep” cycles, RX “Active cycles”, TX “Active cycles”  In-Band Hot reset  Support for downstream traffic –CPU configuration registers programmable wirelessly –Operating system instruction set support –“Send to” node selection capability –“Receive from” node selection capability  Node ID wireless reprogram option  Event-Based Queries and Lifetime-Based Queries support

14. 14 Transmit Cut-Through Data Path

15. 15 Receive Cut-Through Data Path

16. 16 Aggregation of Sensors’ packets

17. 17 Selection of Sensors’ packets

18. 18 CPU Configuration Register Access

19. 19 CPU Register Map ADDRFunctionDATA[2:0] Description 000NODE IDData signifies the NODE ID (default value selected using jumpers) 001TX MODE100 – TX Cut-through (default) 001 – TX Aggregation 010 – Select (parameter A relevant) 111 – Select (parameter B relevant) 010RX DUTY000 – X sec ACTIVE Y sec SLEEP 001 – Z sec ACTIVE N sec SLEEP …. 011TX DUTYSame as RX DUTY except it applies to transmitter 100RECEIVER NIDSend packets only to the node specified by these 3 bits (111 – reserved for broadcast, 000 – default value for base station) 101BATTERY LIFERO register (packet aimed for this register will trigger a transmit packet with BATTERY LIFE information 110Reserved 111Reserved

20. 20 Duty Cycles  RX Duty Cycle (For example: wake up every 30 s for 1 sec)  TX Duty Cycle –Sensor TX side and Transmitter TX side can be decoupled –Transmitter might be turned on only if sensor detects an important information –Sensor TX side and Transmitter TX side can be turned on at the same time regardless what data is being sampled

21. 21 In-Band Hot Reset  The way to reset the node wirelessly  HOT = 1 signifies the hot reset insertion  The entire packet after the preamble should be all 1’s (packet includes only 1 DATA[5:0] word)  If HOT = 1 but the packet has some 0’s drop the packet - no reset

22. 22 Support for downstream traffic  Capability to program the node from the base station or any other node  Capability to receive OS instructions and digest them  Node recognition capability –“Send to” node selection capability –“Receive from” node selection capability

23. 23 Node ID wireless reprogram option  Node ID is programmed using jumpers (problem: cannot go into the bird’s nest to switch jumpers’ values) or using the default factory setting or using EPROM (EEPROM) etc…  Solution: Wireless ability to reprogram the default value

24. 24 Event-Based Queries support  Event-Based Query is the way to program the node to send the data acquired only if the programmed parameters are met –ON EVENT bird-detect (loc) SELECT AVG (light), AVG (temp), event.loc FROM sensors AS s WHERE dist (s.loc, event.loc) SAMPLE INTERVAL 2 s for 10 s

25. 25 Lifetime-Based Queries support  Lifetime-Based Query is the way for user to program the query duration in days, weeks or months. –SELECT nodeid, accel –FROM sensors –LIFETIME 30 days (Note: we do not plan to have day/month/year precision but rather permanent sampling, no sampling, even-based sampling, short-period sampling)

26. 26 Questions from the Proposal Presentation (1)  Internal tri-state buffer use? –Internal tri-state buffers is not planned to be used. We plan to use simple multiplexers instead.  If receiver is asleep how are you going to get the data? –We will have to make sure that the receiver is awake at the right point of time (synchronization needed, programmability support provided by our CPU)  How do you distinguish 2 sensors if you use the same 3-bit addr for both? –Sensor ID field is used to distinguish among sensors.

27. 27 Questions from the Proposal Presentation (2)  How do you decide whether to send data or not? –Configuration registers provide the ability to decide the operational mode. They will drive decisions when to sample/send data.  Run the CPU fast, sample quick, power down, go to sleep in between samples. Saves Power! –We will research more on this one. At this point we are not sure that with the faster clock we will save power.  Is there a common power source between CPU/sensors/transceiver? –Yes and most likely it will be 2 AA batteries.

28. 28 ?