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Forum Index : Windmills : Update on the PicLog
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I've had some good feedback on the PicLog project, and some suggestions. I'm working on a updated version of the PC software. The new version will include.... 1. HTML page output, as I used on my web site. This means I can look at my windmill logs from anywhere in the world. 2. Excel file output. PicLog can create an excel file with the windmill data. Anyone experienced in Excel can then create graphs and reports. 3. Fixed a few bugs. I'm also drawing up a new circuit diagram to show you how to connect a wind speed input ( Magnet, reed switch ). This can either replace the windmill RPM input, or replace the MosFet drive output. If you decide to use the Mosfet drive as a windspeed input, it means you loose the battery charging control side of the PicLog, but you gain an extra measurement for your logs. Give me a few days and I'll post the updates. 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 |
Sounds great Glenn ! I was thinking it would be nice to have a windspeed sampling each time it recorded the rpm, amps and watts. Would give you a much better idea of what the turbine was really doing ( or not doing ). Can't wait to hear about the results ! Keep up the great work ! |
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| C-Systems Newbie Joined: 09/07/2006 Location: United StatesPosts: 3 |
I've been looking forward to this Glenn! I've got a copy of your original program, but have been waiting for the update before doing anything. Could the RPM input be a cycle speedometer? Until next time ! |
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| RossW Guru  Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Surely it would be vastly more efficient to use the output signal from the turbine/alternator itself?. It only needs calibrated once (and that's a digital thing, the number of poles will never change, and will always be an integer number - except I suppose for the situation of guys using belt/chain/gear drives!). One can sniff the raw AC from the turbine (single phase) or one phase (polyphase), or perhaps sense ripple from the output of the rectifier? The ratio of pulses-to-RPM will always be constant for a given machine config, and you don't have to go climbing up to (or pulling down) your machine to add bits. (The other consideration here is lightning protection - a reed switch and magnet are nice and easy - but running an open circuit (relatively high impeadance) circuit directly into that poor little PIC ain't gunna win you any friends when the spikes come!) |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I dug up my old wind speed meter on the weekend, it used a bike computer and magnet/reed switch. I was going to use this as a wind speed input to the PicLog using the same program method as RPM measurement, that is, count the number of pulses per second. But I soon realized the pulses from the reed switch were too far apart to get good results, ie at low wind speed I would only get 1 or 2 pulses per second. However the picaxe has commands for measuring pulse duration in milliseconds, so I'll use this method for the wind speed measurement. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
There are two ways to calculate RPM: count revolutions in a given time period, or calculate the recriprocal of time between revolutions! In my genset controller, I display both frequency (Hz) and engine speed (RPM) - by generating an interrupt on the zero-crossing point (mains) and from the closure of the points (well, hall effect device). Each time I get an interrupt (a or b), I count the elapsed count since the last, and calcualte the appropriate Hz/RPM. With a CPU running at 8MHz (and a hardware counter running off the same oscilator), quite accurate speeds up to 5-6,000 RPM are easily achievable, and if I remember correctly, to at least one decimal (if not two) Hz, updated 100 times a second! Unlike counting revolutions in a given time, the timing a cycle gives increasingly accurate results at lower speeds. (It does depend on counter bits and clock frequency, but that's just basic math - if you clock too fast and speeds are too slow, you get counter overflows). Do you want my code? (Not that it's hard to write your own to do this...) RossW |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Well its getting there. Still a few little problems to sort out, mainly in wind speed and logging. Windspeed has a problem with points bounce, I'm using a reed switch and magnet on the aneometer. I can put a capacitor across the reed to smooth out the bounce spikes, but this may affect accuracy at high wind speed. Trying to find a happy medium. Software is almost finished, a few minor bugs to flush out. I know I said I would have this all done a week ago, but you know how goes, too many little projects on the go. Remember you can see the live logging data on the PicLog page. Ignore the WindSpeed readings, remember I'm still working on it. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Xcat Newbie Joined: 13/07/2006 Location: AustraliaPosts: 6 |
Gizmo, Why don't you use one of the hall effect sensors out of a F&P motor in place of the reed switch? No bounce problems there. HTH Xcat Brisbane QZ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yes you could use a hall sensor. I've drawn up circuits to show connections for reed switches, opto switches ( slotted vane ) and hall sensors, and will show these when I update the PicLog page. I'm using a reed switch because it only needs 2 wires, nice and simple. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Software debounce? If you don't have "timers" spare, a trick I used to use a couple of decades ago was a shift register. Read the state each pass and shift in one end. Check the word for all 1s or all 0s within a mask of appropriate length (depends on speed you're shifting stuff in, and the bounce period of the reed). You can do some fancy bit-stuffing to improve response if its required, but I rarely needed to. (I used to build all sorts of weird industrial controllers). |
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