Ok, I wasn't clear and I paid for it ! So let me explain a bit more.
The parallax propeller chip is managing the 17ft boat. We currently monitor environmental things like water temp, water speed, ground speed and GPS position. The goal was to expand that when we replace our ICE with electric. The project grows in software first, then in hardware.
With some help from the propeller forum, we are about to install monitor circuits that will monitor the 4 individual batteries including charging, and their overall health/capacity (battery temp etc). We can monitor the small windmill that charges the boat when docked as well as the twin chargers. Xbee will send data to the house computer for display.
We would like to be able to tie this same system to the speed control for the boat. Then I can look at consumption vs supply and we can do some experiments. I can of course connect a servo to a pot and have speed control. Thats kind of a no-brainer and probably where I will end up but....
Many of the AXE controllers support a serial interface which I suspect could give me a lot of useful information about the motor, the consumption at the head, losses etc. Even the temp of the controller itself might be worth looking at. But sadly, the AXE controllers use a proprietary format to talk to the Windows based PC. And I am certainly too lazy to reverse engineer that. And it looks like I can read it from the PC, but not control it.
We have not purchased the motor because for us, the controller will make the motor decision (brushless et al). My goal is not to run the motor through the prop chip. That I do in RC/robot land all the time but this is a whole different scale when we start in the 4-8hp range. The prop chip will provide an input signal and I've got a wealth of approaches to provide data to the controller from serial to midi to ethernet and almost everything in between.
Ideally, I would like a speed controller that I could set speed directly from the micro and read data back through serial or other 'open' connection. To the original specs, 48V / 400W. Dual motor control would be preferred.
If all I can do is the servo-pot connection, it's not fatal. Just lost opportunity for me. And yes, we will probably add automatic steering next year when we build the new boat. But I think this is enough on our plate for the summer.
Thanks
--- In electricboats@ yahoogroups. com, vectorges@.. . wrote:
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> The Arduino (about $30) does PWM as a standard part of its architecture. The question seems to be fitting MOSFETS (or whatever) on the motor controller side.
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> -----Original Message-----
> From: hardy71uk <p0054107@.. .>
> To: electricboats@ yahoogroups. com
> Sent: Thu, Apr 29, 2010 4:51 am
> Subject: [Electric Boats] Re: Controller for 300w and microprocessor
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> The simple way to do it is with a voltage controlled controller . then the interface can be a very basic digital to analog convertor circuit. the somewhat more technical way is to generate pulse width modulation in the micro.
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> Chris S
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> --- In electricboats@ yahoogroups. com, "williamdickenson55 " <williamdickenson55 @> wrote:
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> > I've been digging through the various controller circuits and while I am finding more than a few excellent controllers, I am not finding one that can be controlled by a microprocessor.
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> > Anyone know of a good one ? I've got everything running on my test setup so I don't have the real motor yet either, but I need the controller to get the software written. I need somewhere around 48V / 300-400W.
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> > I thought I saw one that could control 2 motors but that may have been in a parallel universe.
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> > Thank you all
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