1 Progress Report January 2017 Maximus ByamukamaEnergy Harvesting, Storage and Management for Automated Environment Monitoring in the East African Region Progress Report January 2017 Maximus Byamukama

2 Administrative ProgressTuition has been paid for 2015/2016 Revised Proposal has been submitted. Awaiting communication on presentation date. After this I will request for 2016/2017

3 Changes There were 6 objectives. There are now 5.This specific objective was removed. To obtain the optimal point in the balance between energy density, charge time and discharge time so as to maximize portability and availability. Objective Progress Low power gateway 50% - needs hardware Practical solar panel sizing 75% - proposal phase LIC self-discharge 30% - first experiment set up Wind energy accumulation 5% Battery degradation from over-discharge* 0% System integration??

4 Main objective To increase the Mean Time Between Failures (MTBF) of AWS due to energy-related causes To improve?

5 Progress - January January PlanPlan A: Acquire another board based on ATMEGA128RFA1 which exposes more free pins to work with. Plan B. Attach current sink node to another low power MCU. MCU (ATMEGA168) arrived on Monday 22nd

6 Walk through – worst case scenarioReady to deploy Sink node = 12mA ATMEGA168 = 25mA (active, worst case scenario) SD card reader = RTC module = GPRS Uplink = 200mA bursts (200mA for 60s per hr = 3.3mA) Total worst case = 45mA.  48 hrs on single 2200mA Li-ion battery (on paper) . Perhaps 20-30% less in practice.

7 Walk through – achievable designSink node = 12mA  remove this. Replace with RF transceiver. Program for low power idle state (2uA) with interrupts. E.g MRF24J40 OR Use MCU with in-built transceiver (e.g. ATMEGA128RFA1) ATMEGA168/128RF  program to be woken up by radio interrupt Switch out all XT oscillators from 16/8MHz to lower frequency (e.g 32kHz) Remove all linear regulators and connect directly to power. SD card reader  switch off completely when not in use RTC module  switch off completely when not in use GPRS Uplink  no solution for this yet. Apart from Investigate power cost versus frequency of data transmission. 3G? Total worst case = approx. 5mA.  18 days on single 2200mA Li-ion battery

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9 A few reactions Related work on low power gateways – there is a lot….in Europe. Emerging battery technologies – large sub section in proposal (LiFePO4, LiSOCl2) – flat discharge curves that permit direct connection hence eliminate some power electronics. Power electronics can consume upto 50% of available energy. (e.g step-down converters in WIMEA Gen1)

10 Papers Low power gateway – draft paper with comments from ACMDEV last year. Target is March 2017 (IEEE AFRICON 2017). Objective 1 Practical solar panel sizing – partial data from students experiments last year. Target is June Objective 2.

11 Challenges Contiki. An uphill task. My research reveals no direct linkage with low power. Low power will depend heavily on hardware selection, re-design and programming methodology. Its used a lot in research but majorly for networking in embedded systems Deliverable is : low power gateway (more urgent for WIMEA). We can have 2 batches of AWS. No Contiki vs. Contiki