1. Remote Management Thomas Sprinkmeier

3. Requirements/Constraints ● Real-time access ● File transfer ● No copper service – Power – Phone ● No schedule ● No locals

4. The Obvious Solution $ python Python 2.5.2 (r252:60911, Oct 5 2008, 19:24:49) [GCC 4.3.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import RemoteManagement Traceback (most recent call last): File " ", line 1, in ImportError: No module named RemoteManagement >>>

5. System Overview ● Control Circuit ● Solar Panel ● SLA Battery ● UMPC ● 3G Modem ● Diesel Generator ● PCs

6. Solar Panel “120W at 12V” means: ● V OC : 21.8V ● I SC : 7.14A Ideally should have “maximum power tracking”

7. AGM VRLA Battery “12V 100AH” means: ● 10.5 to 12.7V (14.4) ● 50 AH usable ● 3-stage charge – Bulk (<14.4V, 80%) – Absorption (14.4V, 98%) – Float (13.4V) ● Diesel > 10,000 WH/L

8. 3G Modem ● Slow (esp. uploads) and Expensive! – Efficient access! ● Non-routable IP address (10.x.y.z) ● Occasional crash ● Windows Friendly!

9. Control Circuit ● Charge Batteries – Main – Generator – UMPC ● Regulated PSU V in = 10.5V to 21.8V ● Digital I/O ● Analogue Input

10. Arduino Decimalia ● Open Hardware ● USB-RS232 ● Microprocessor ● Analogue Input ● Digital I/O ● PWM Output

11. Arduino DIO ● Tri-state – Input (tied/high Z) – Output (40mA) ● Also – RS232 – PWM – IRQ – LED – SPI

12. PC ● TCP/IP access – ssh/scp – PuTTY/WinSCP ● Power Control – BIOS – WOL – Relay across button ● Monitor HDD LED

13. UMPC ● EEE 700 ● EEEbuntu 8.04.1 ● Slightly modified ● USB ● 10/100 UTP – Wi-Fi? ● Webcam

14. Interface ● Summary ● Status ● Control ● History ● Snapshots live demo (I hope!)

15. If you can read this...

16. CGI ● DIO ● ADC ● Summary/History ● MRTG Plots ● Snapshot ● PC-PWR ● UT

17. MRTG Plots ● Voltages ● EEE battery state – batc ~ availability ● df ● mode ● up/idle time

18. Main Battery Voltage ● Very sensitive to cloudy days ● Battery charge estimated from V ● No Current sensing

19. MRTG Plots cont. ● Daily – 5 minutes ● Weekly – 30 minutes ● Monthly – 2 hours ● Yearly – 1 day

20. Software ● Arduino MGR ● Arduino Interface ● CGI ● MRTG Plots ● misc

21. Arduino MGR ● Charge Batteries – State Machine – thrashing ● ADC/DIO ● Watchdogs ● 49.7-day proof

22. Arduino Interface ● Talk to Arduino (RS232) ● Talk to socket – CGI – PC-PWR – netcat ● History ● Watchdog ● Hook script

23. misc ● Perl – /etc/remote.conf ● cron ● screen ● autossh ● ntp ● ACPI hooks ● udev

24. Solar Input ● Protection ● Monitoring

25. Solar Regulator ● “12V” = 21.8V oc ● Positive Voltage Regulator ● Diode, Caps “polite” ● Peak power tracking

26. Peak Power Converter ● Series Regulator V in > V out I in ~ I out P in > P out ● DC to DC converter P in ~ P out V in > V out (step-down) I in < I out ● Efficiency gain – More power in – Less power wasted

27. Arduino PSU ● Positive Voltage Regulator ● 9V for Arduino ● Diode logic: Solar or SLA

28. EEE PSU ● Positive Voltage Regulator ● 9.7 V (EEE 700) ● “Low Drop Out” 10.5V – 0.8V = 9.7V ● Resistive Divider to tune output

29. DIO ● Currently Output only ● Buffer/Driver 40mA to 200mA ● “relay coil” = Inductor – Fly-back diode ● Optocoupler? ● Solid State Relay?

30. Relays ● Fail safe! – All except USB N/O ● 3 spare

31. ADC ● Resistive divider – V out = V in R 5 /(R 5 +R 6 ) ● Optional Zenner – non-linear! ● Low-pass Filter – T = 1/RC – Spike protection ● 2 spare

32. Results ● > 60 day uptime on Solar alone – A few close calls! – Relocated, else > 90 days ● Occasional comms outage ● Full control of remote PC – Power on/off – ssh

33. ToDo ● Diesel Generator (!!!) ● New Circuit: – Peak Power Tracking – Battery charge – Arduino Nano – PCB ● Wind Power

34. Summary ● Thanks https://code.launchpad.net/~thomas-sprinkmeier/+junk/remote thomas.sprinkmeier@gmail.com