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Forum Index : Windmills : New PicAxe windmill controller
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hey All. I've got a new PicAxe windmill controller in the works. This one is based on the little PicAxe 08M chip, and has a simple dump regulator, so when the battery voltage is too high, the controller switches a dummy load across the battery to drain off some power, similar to the Oatley Electronics windmill controller. But its got a few "extra's". Using a PC connected via a serial cable, the PicAxe sends infomation to a little program I wrote. The program displays Battery Volts, Amps ( either + or -, so you can see if your battery is charging or discharging ), Watts ( easy as, Volts X Amps ), and windmill RPM. RPM is measured by sniffing the AC before the bridge rectifier. The software also logs the data, and displays the results on a graph, so you can see Volts, Amps, Watts and RPM over a hour, day, week, etc. Its all working, I just need to tidy up the software and document everything, so by next weekend I'll start a new diary entry to show everyone how it all works, and where you can download the software. All up parts would cost about $30, including the PicAxe chip, but not including a computer! 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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whirlybird Newbie  Joined: 08/02/2006 Location: Posts: 27 |
Well I will start the ball rolling here. I think Mr Gizmo that this will be a very handy Gizmo indeed. Cant wait for the rest of this little baby I have a spare axe chip or so here.  I am because I am.I am not always right but often I am. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Teaser photo... 
As you can see there isn't much to it, most of the work is done by the software in the PicAxe chip and the attached computer. A computer is only needed for logging, the controller will work fine without it, though you will need a PC for the initial setup. I use a relay to switch the load across the battery. I did consider MOSFETs, but relays are cheap and easy to use. The controller sends logging information every second. I did consider increasing this period to reduce power consumption of the PicAxe, but total current draw is only 8mA, bugger all. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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WXYZ Newbie Joined: 30/04/2006 Location: CanadaPosts: 20 |
Gizmo, You say that it sends the info to a computer. Is that USB or RS232 or? Joe. "Failure is an option." |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
RS232 port. The PicAxe chips dont support USB, and serial port comunication is very easy to program. The speed is 4800, meaning you can use a LONG serial cable. The cable I'm using is 20 meters, but you could go several hundred meters. USB is limited to 10 meters tops. The picaxe sends the following every second.. [<V000V><A000A><R000R><M000M>] Replace the "0"'s with real values . V=Volts, A=Amps, R=RPM, M=Mode ( dump load ). The V and A values are approx 500, calibration is done at the PC. R is pulses per second, again converted to RPM at the PC. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Its finished at last. You can find the details at the bottom of my Projects page. http://www.thebackshed.com/Windmill/AssemblyA.asp I wouldn't consider it finished, needs some work to enhance the software. Buts its all working. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Bryan1 Guru  Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Hiya Glenn, Well mate I like your windmill logging project that much I'm going all out and buying some picaxe chips and make up your project But as I don't have a computer in my shed as yet and I do have plenty of 512kb and 1 meg eprom chips from microchip I'll re-write the code to log to the eprom then when I connect my laptop download the infomation stored. I've got a heap of research to do and Stan Swan's site has plenty of info on picaxe chips but your computer program might need modifying to cope with the influx from the stored info on the eprom and this is where I'll be stuck as I don't have vb6 or any exposure to that program. Might be time for me to find vb6 and digin. Anyway I'm going to sit down and design up a circuit board that can be easily etched and I'll gladly share it around. Anyway Glenn if you would like some of those eprom chips and a few other free samples I've got in the past just let me know and I'll post them up to you.
Cheers Bryan |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hiya Byran You may need to use a 18X or 28X chip to do logging into a eprom, as the o8M chip has no free outputs. I have no expierence in using eprom chips with the PicAxe, but there is a lot of info on the net about it. If you get it working please let me know, would be very interresting. The PicLog software will accept logs from the picaxe as fast as it can send them. It listens to the serial port, and as soon as it gets valid data it starts processing the info. So you should be able to send several hundred records per second from the PicAxe. The only problem is time keeping. The PicLog program uses the PC clock to record a time against each log entry as it arives from the PicAxe, so if you send all the data in one lump, the time info will be spread over a few seconds, not several hours. But we can get around this. Sound like an interresting project. Yesterday I got my first real figures from the PicLog. Set it up in the morning before work, and checked it when I got home. I had a full day of data, recorded every 30 seconds. I could see the wind pick up during the day, peaking at about 11am, and then slowly died off to about 4pm. Just past 11am I had a peak power of 12 watts. All good stuff! Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Glenn, Good work , and I'd like to buy a pcb or kit if you ever get it to that stage. ___ "I had a peak o/p of 12 watts" ---- gee, so often have I seen this , the guys that get Kilowatts must live on a different planet ,lol. Bruce Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Heya Bruce. Been a while, hows those big timber blades going. Yeah the wind has been weird of late, bugger all worth talking about. Today I had a peak of 5 watts! I've thought about putting together a kit of this controller, just the PCB and pre-programmed PicAxe, but I think it still has a lot of "evolving" to do before it could be called a finished design. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Hiya Glenn, Well after reading your latest post I've checked out the 18x and bigger chips and the price of them  . I don't know if you've heard of the Oshonsoft basic compiler ? but that compiler uses a structured basic for pic chip's and is much more powerfull than the picaxe will ever be. The licence for the software is only about $30 Oz so it isn't expensive and I bought the license thru dontronics here in Oz. Over the last 2 years I've got quite a few 16f pic free samples so for me it would be a shame to spend a small fortune going the picaxe way. But if you like I do have the pcb software to design a pcb for your existing circuit layout which I'll gladly make the circuit borad for this forum. Anyway my wife said my tape drive wind genny was going that quick she couldn't see the blades so a data logging project is my main project on the board. But as I'm away everyday working I need to set up a data logging setup asap.
Cheers Bryan |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Bryan. Where are you getting you PicAxe chip prices from. The 18X chips is $13.50 from Oatley Electronics. The 04M ( as used in the controller ) is ony $4.70. I'll look into Oshonsoft, would be nice to have more programming options, but I dont want to learn C. I already spend most of my day programming in VB6 and ASP, no room left in my brain for another language, its officially full. Yes would be very interrested in PCB boards. Using the router to make circuit boards is fun but time consuming. The router only took a couple of minutes to make the board, but there was a couple of hours programming the cnc file. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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windstuffnow Newbie Joined: 30/06/2006 Location: United StatesPosts: 31 |
That is one slick unit Gizmo! I want one ! Unfortunately my electronics skills are somewhere below the 101 area. What would it take to get one built? Have Fun! Windstuff Ed |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Ed. Give me a couple of weeks and I'll see what I can come up with. The design is still evolving at the moment, especially the software, but its close to been finished. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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