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Remote Voltage Monitoring of Wnd/Solar — Parallax Forums

Remote Voltage Monitoring of Wnd/Solar

WD8MBEWD8MBE Posts: 8
edited 2011-10-14 01:58 in Accessories
I am new to this forum and hope this subject has not already been discussed. I have searched the forum and really didn't find any answers.

I have a wind/solar setup and the battery bank and everything is located in my garage. I would like to remotely monitor the voltages on my computer here in the house. Understand XBee's can be utilized for this type of situation.

Question: Does anyone already have the circuitry designed along with the required programming? Or can someone assist me on putting this remote together?

All and any help is appreciated.

Tom, WD8MBE

Comments

  • Mark_TMark_T Posts: 1,981
    edited 2011-08-29 09:35
    The voltage and current sensing can be made easy with a module - I've seen one that senses voltage upto about 60V and current to about 50A and scales both to a 0 to 5V analog signal. As I understand it Xbees incorporate an ADC can can be made to read values from some of the pins automatically (although I don't have direct experience myself).

    Quick search shows its the AttoPilot voltage/current sensor and I was wrong, it does a 3.3V analog output. 50V and 90A max. There are other current sensors available of course and a resistive divider can give you a simple voltage sensor.
  • alex123alex123 Posts: 102
    edited 2011-08-29 11:35
    I guess an ideal thing would be a WiFi module that would connect to your home WiFi router. As far as I know Microchip makes WiFi boards that run a web server. Not only could you access it from your computer at home but (if you setup your router correctly) anywhere in the world where Internet access is available. (e.g. from a hotel in Hawaii while on vacation... :))
  • WD8MBEWD8MBE Posts: 8
    edited 2011-08-30 06:04
    Well I have heard that I could take 2 XBee's and linked them together. One in the garage hooked in a way to monitor the voltages and transmit the info to the receiver XBee located in the house. That in-turn would interface with my computer and display the readings.

    I hope someone has some sort of information on this type of setup.

    Thanks,
    Tom
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2011-08-31 09:11
    Can we presume that the setup in the garage already uses a BASIC Stamp or Propeller to acquire the data? It is very easy to set up a serial link between an XBee in the garage and one in your house, just as though you had them connected by a cable, and it is possible to elaborate the interface. We need more details about the existing setup before we can help much with the programming.
  • WD8MBEWD8MBE Posts: 8
    edited 2011-08-31 11:51
    As of now, there is no setup. I have a Basic Stamp II but it is not being used for anything. Only setup is the wind generator and solar panels to my battery bank. I haven't even bought the XBees as of yet.
    Old Man Winter is just around the corner and I want to be able to monitor the system in the garage on my computer.

    I appreciate any input.
  • bsnutbsnut Posts: 521
    edited 2011-08-31 18:59
    What you are trying is not hard to do. I have done this for my solar charger on the ship that I am restoring to charge generators batteries.

    This is, I what suggest you to do, which I have done for my solar charger. I used a Analog Optocoupler. This circuit separates your Windmill high voltage from the microcontroller voltage.

    You are wondering what a Analog Optocoupler is. A Analog Optocoupler has a LED on one side (high voltage) and a photo resistor on the other side (low microcontroller voltage), which both the LED and photo resistor are isolated from each other.

    I can provide you a drawing for you if you want or you can do a Google search for Analog Optocoupler circuits.
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2011-09-01 08:59
    WD8MBE, an excellent starting point for you would be the XBee tutorials by Martin Hebel:
    http://www.parallax.com/portals/0/do...orial-v1.0.pdf

    If you have 4 or fewer voltages to monitor, consider using the XBee's internal analog transmission capabilities. Those are described in the tutorial in chapter 6, under API mode. You could then attach a second XBee to your computer at the house, and see the readings on screen using the XCTU program that accompanies the XBees. In the garage then you would need only the XBee itself and the necessary level shifters and isolators to sample the voltages. No Stamp or Prop required, and the only programming is that required to configure the XBee as described in the tutorial. A good way to get started.

    For a more capable setup, you could have a Stamp or Prop with an analog to digital converter and other electronics in the signal path. That would allow a lot more, for example, to do math on the readings so that they would be displayed with their actual units rather than the units as scaled down for the converter.
  • icepuckicepuck Posts: 466
    edited 2011-09-01 16:06
    What are you using for charge controllers? Why I'm asking is some newer(i.e. more expensive) controllers have communication ports on them, some are advertised as having com ports and some are not.
    If you are lucky enough to have a com port then that eliminates the need to do any ADC since that will be done by the controller and possible be available via the serial data.
    -dan
  • bsnutbsnut Posts: 521
    edited 2011-09-01 20:48
    Here is the link for the datasheet for the Analog Optoisolator, which is same as an Analog Optocoupler. Look page 48 of this PDF.
    http://www.datasheetcatalog.org/datasheet/perkinelmer/VT500.pdf



    As Tracy Allen states, you can use the XBee's internal analog transmission capabilities and the Analog Optoisolator will be connected to the XBee analog I/O pins, which is the best way for you to do. You will also need to look at the XBee datasheet for proper connection of the Analog Optoisolator.
  • WD8MBEWD8MBE Posts: 8
    edited 2011-09-02 06:28
    Yes, I have used Optoisolators before. In fact, I used them for my interface between my computer and Ham Radio equipment.
    I wish I had a different charge controller, but no, this one does not have any ports.

    I was just trying to come up with a simple circuit using the XBees to monitor a couple of voltages in the garage. So if it is just a simple circuit of connecting optoisolator to an XBee, that should be to difficult. Also, this will be the 1st time I have ever used the XBees so this will also be an educational project.

    Any other suggestions or hints and references are greatly appreciated.
    And thanks to those who have responded thus far. I enjoy a forum where different ideas are kicked around and people may have a better way of doing a project.

    Thanks,
    Tom
  • bsnutbsnut Posts: 521
    edited 2011-09-03 23:56
    I was just trying to come up with a simple circuit using the XBees to monitor a couple of voltages in the garage. So if it is just a simple circuit of connecting optoisolator to an XBee, that should be to difficult.
    I will be willing to provide you with a simple Analog Optoisolator schmatic to interface with XBees and microcontrollers for you if you want.
  • WD8MBEWD8MBE Posts: 8
    edited 2011-09-05 14:10
    William,

    I would appreciate the circuit interface between the opto's and the XBee. I have read that the Xbees can read certain values directly but have not found any detailed information on this. Like I stated, I would like to monitor some voltages of my solar/wind generator and display and/track these voltages on my computer in the house.

    Again, I thank everyone who has provided information so far and hope a positive solution is near.

    Tom, WD8MBE
  • Martin HebelMartin Hebel Posts: 1,239
    edited 2011-09-05 19:42
    The XBee can monitor up to 3.3V (the supply voltage) and send that ADC data to a remote unit directly as a frame of data to pull out that data using API mode or to drive a PWM output to monitor that data.

    See my "Getting Started with the XBee" text from Parallax, there are example programs illustrating use.

    http://www.parallax.com/go/xbee

    -Martin
  • bsnutbsnut Posts: 521
    edited 2011-09-24 02:00
    Tom,

    I am going to point you to this Xbee Tutorial that Martin wrote www.parallax.com/portals/0/downloads/docs/prod/book/122-32450-XBeeTutorial-v1.0.pdf if you haven't read it.

    I also provided you the basic drawing for you and I am little late posting it for you.

    BTW,Please let me know if you can't view the attachment. It was created using ExpressSCH software.
    sch
    sch
    Xbee Voltage Interface.sch
    4K
    Xbee Voltage Interface 1.jpg
    1024 x 773 - 37K
  • WD8MBEWD8MBE Posts: 8
    edited 2011-10-05 11:16
    Thanks for getting back to me.
    Sorry I did not reply. Have been tied up in other matters.
    I can view the attached thumbnail but cannot open the XBee Voltage interface.sch.
    I am working on a test setup using a Basic Stamp 2 + LT-1298 + sending the information over the XBee. Not sure which one will get done first or work the best, but trying it from 2 angles.

    Tom
  • bsnutbsnut Posts: 521
    edited 2011-10-14 01:58
    Tom,
    That is ok. The thumbnail is the same thing as the schematic.

    You will not need the cap that is shown in my drawing. But, double check Xbee PDF to make sure. If, I am right my circuit gets connected to Vref and analog I/O pin. This based on the Xbee pin out.
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