Super Moon Shine

Discussion in 'General Science' started by nsaspook, Aug 10, 2014.

  1. nsaspook

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    Aug 27, 2009
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    This is last nights chart (from about 10PM to sunrise) into about a 3K load from about 500W total of panels. The hump at about 800 samples is where a separate panel of 120W started getting light from the moon. Maybe 20uW at max power. [​IMG]

    The DAQ is a Linux based NI-DAQCard-700 12-bit diff-input card using my kernel driver with a 128X oversample to squeeze a few extra bits of resolution.
    http://git.kernel.org/cgit/linux/ker...s/ni_daq_700.c
     
  2. THE_RB

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    Very cool! Thanks for sharing. :)
     
  3. nsaspook

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    I'm sure with MPPT I could get the power to 100uW and charge my cell phone. :D
     
  4. studiot

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    Very cool, seconded. :cool:
     
  5. djsfantasi

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    Why did my mind immediately go to alcohol when I saw this post?
     
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  6. alfacliff

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    I've been wondering about how much solar panels put out when lightning is the area, are they fast enough?
     
  7. nsaspook

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    Last edited: Oct 9, 2014
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  8. BR-549

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    I moved to Roanoke in 2001. I have not been able to see an astronomical event since. I tried again this morning....but no luck. I enjoyed the pictures.
     
  9. nsaspook

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    Getting ready for the next Super Moon Shine on Sept. 28. Tuning up the detector electronics and software for the solar panel detector. Might even have a little late night party outside if the conditions are good.

    I'm planning to use a TI ADS1220 Low-Power, Low-Noise, 24-Bit, ADC (+- 2.5 for the analog power and 3.3 for the digital power from batteries) for the front-end with a PRi2 custom kernel SPI driver to process the signal data. It should be a fun project to see how much raw luminosity data I can capture on a good night.
     
    Last edited: Aug 29, 2015
  10. nsaspook

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    I've got the basic hardware running but the ADS1220 is a bit of a kludge as I didn't have a dip16 to TSSOP adapter but did have a breadboard adapter. :mad: I love to solder tiny leads.
    [​IMG]

    Sensor power is from 2 9volt batteries using a 3.3 LDO regulator for the digital and two 2.5volt Zeners for the +- analog input supply to the ADC. The other two chips are for a optical isolation circuit that's not used with the RPi and has it's own 5volt switcher regulator that's disabled here.
    The two power indicators are LEDs in series with the Zener dropping resistors and the other LED flashes when a conversion is complete.
    [​IMG]

    The brass plates are ground plane/shields for the input filter and are connected to the metal box for (some) electrostatic shielding.

    From the program info header:
    * A special version for the TI ADS1220 SD ADC converter chip (and MCP3911 later) for low voltage sensing and
    * solar panel panel light detection. +- 2.048, 1.024 and 0.512 voltage ranges @ 20 bits of usable resolution
    * ADC is in single-shot conversion mode @20SPS, PGA disabled and gain from 1, 2 and 4 in differential
    * signal detection mode, 50/60Hz rejection enabled. 500kHz SPI clock with direct RPi2 connection
    * Analog +- 2.5VDC from Zener regulators for the bipolar input stage with external 2.5VDC Zener input
    * signal protection.

    [​IMG]
    Connected to the RPi2 with a breakout for SPI signals. The input is shorted to measure offset (~40uV) and Vrms (~10uV) noise. The calibration source is a AA battery measured with a Fluke 177.
    [​IMG]

    The output of the ADC is binary twos complement so the RAW output has been converted in software to bipolar binary twos complement format for the user library.

    Now I need to make the solar panel external over-voltage protection and load resistor network for the tiny power input calculations during the full moon.

    With my luck we will have rain or clouds that night but the entire system will be battery powered just in case a late night trip to the top of Hood is needed with some star-gazing friends for a party. :)

    Software and hardware page: https://github.com/nsaspook/nidaq700/tree/master/supermoon
    The circuit diagram is the generic one from the ADC chip PDF except for the voltage regulation and optical circuit.
     
  11. nsaspook

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    Running some drift measurements with the AA battery calibration source. I can see a steady decrease in voltage that looks to be the battery voltage very slowly decreasing by a few tenths of a uV every few seconds. The Null voltage is read by switching the ADC Mux to both inputs shorted to 1/2 the analog voltage internally.

    [​IMG]
    [​IMG]
    [​IMG]

    Too bad we can't get mercury oxide batteries anymore.

    The logger program "moonlight' is here: https://github.com/nsaspook/nidaq700/tree/master/supermoon/bmc
     
    Last edited: Sep 6, 2015
  12. nsaspook

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    Running some baseline tests with a 80W solar panel pointed up in the backyard connected to a 1K load on the ADC input. Currently a fairly dark sky with little cloud cover.
    [​IMG]

    [​IMG]
    [​IMG]
    Panel voltage levels seem solid for low light conditions at about 0.005175 volts into a log file for later display. I should be able to get a 8 to 10 hour run on fresh cells.

    [​IMG]
    Moon rise tonight is 2:19AM 18% Illum. 245,846 miles and is 12:18AM 99% Illum. 221,798 miles on the night of the 27th at the lunar noon.
    http://www.timeanddate.com/moon/usa/portland-or
     
    Last edited: Sep 9, 2015
  13. nsaspook

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    Used my 'new' Omega CL511 calibrator set on 2000mV to dial the voltages in.
    [​IMG]
    RPi2 SPI 24 bit data stream after 8 bit read command reading solar panel voltage 0.016274V (no moon, just night sky)

    [​IMG]
     
    Last edited: Sep 10, 2015
  14. atferrari

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    Hola nsaspook,

    Not in line with the thread's subject, I know: what are these caps for?

    Caps nsaspook.png

    Any minimal data about them? Low leakage I presume.
     
  15. killivolt

    Active Member

    Jan 10, 2010
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    Hey, nsaspook. I normally wouldn't say this but; nice "Rack"

    and the panel voltages are cool too :rolleyes:

    kv :D
     
  16. nsaspook

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    It's for a first-order resistor-capacitor filter on each diff input pair to reduce external noise from being part of the measurement. The needed bandwidth is very low. Those are just Mylar capacitors (10 nf 100 nf) and the resistors (1k) are low noise metal film on the analog side.
    http://www.nteinc.com/capacitor_web/pdf/mlr.pdf

    For very low level amplification you don't want to use most ceramic or SMD capacitors as they are microphonic and the very small SMD caps can be non-linear. Any flex of the PCB with an applied DC voltage on it will product a small but detectable signal into the audio range easily. Film Mylars (non SMD) are a good low cost component for a low level front-end.

    http://www.edn.com/design/analog/44...ding-the-distortion-mechanism-of-high-K-MLCCs
    http://www.analog-eetimes.com/en/re...udible-noise.html?cmp_id=71&news_id=222903370
    It's not a good idea to use some of these these types in any quality signal chain without special design and/or layout to reduce noise pickup and generation.

    http://www.millertechinc.com/pdf_files/TN095 Capacitor Noise.htm
     
    Last edited: Sep 10, 2015
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  17. nsaspook

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    I have another one in the shed somewhere. Both are from old VAX disk drives dumpster dived long ago. Super heavy and strong with good rollers with a pull-out steady bar on the bottom so the thing wouldn't tip over when the big drives were pulled.

    I would love to show you my main server 'rack'.

    The first panel has the cooling fans on a temp controller and in the back is the old DEC power conditioner. Power is feed from an online 2kVA UPS with charging power from the utility or solar backup AC power. (also used as a diversion load when the solar energy bank is full)

    Both 4U (8 hard drive) computers run Debian Linux. The one on the top is the main networking computer and firewall for the FIOS connection, home security IPCAM network and a few other things. The bottom machine is for AV media and NAS storage. The Yamaha sound processor is for a FM modulator that uses music from the AV processor that broadcast's music to any radio in the house.http://usa.yamaha.com/products/live_sound/processors/rev7/
    http://www.starkelectronic.com/btc15-7.htm

    [​IMG]
     
    Last edited: Sep 10, 2015
  18. killivolt

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    Jan 10, 2010
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    Really cool.
    Makes my baby "4 ft Media Server and AV Rack" look dinky, especially your premium first order devices with all the connectivity. I'm hoping for the money to install it all this year in the closet next to my Living room, then I'll feed all the wires into the Living room and put the TV above the fireplace, in the end it will provide: AV server for Movies / Gaming console for the kids and Music Studio.

    Nice Job.

    kv
     
  19. nsaspook

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    You can hide equipment in a room if you make a nice facade for it. I had to cover that ugly pipe so I built a fake 'fire place'. The bottom is canvas so air can circulate in and out the heater return in the floor.
    [​IMG]
    [​IMG]
    A little wood working skill goes a long way. (old picture with a CRT TV :p)
    [​IMG]
    [​IMG]
    [​IMG]
    Front projection media room with all AV electronic equipment hidden from sight and screen pulled down below the wood work on the ceiling.
    [​IMG]
    [​IMG]

    It keeps your nice stuff out of the hands of sticky fingered kids. ;)
    [​IMG]

    Don't forget the cooling requirements and soundproofing. In a closed space you will need a forced cooling feed and exhaust to reduce heating even with low power computing above a few hundred Watts unless you want the gear to cook.

    In the winter my rack keeps me warm.
     
    Last edited: Sep 10, 2015
  20. nsaspook

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    On the side of the rack is the satellite/RF antenna switch board for Linux DVB/SDR and standalone DVB receivers for photon reception on lower bands. :D That's a total mess.
    [​IMG]

    NA sat feed of RT Russia (it's a clear channel) from the KU band antenna with HH positioner.
    Intelsat 6 93.0W transponder 12152MHz 20000 Symbol Rate (SR) H Polarization 3/4 FEC
    Quad V/H linear LNB with side dual circular polarized LNB on the KU dish.
    [​IMG]

    [​IMG]
     
    Last edited: Sep 10, 2015
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