CTP Autopilot problems

[hpeer]

They don’t “make” any rams. They distribute electrical rams from a supplier. But you could use their control head to drive someone else’s ram, electrical or hydraulic. PyPilot only makes the AP computer and current driver.

[Bill O]

Originally Posted by a64pilot

If someone would build a box that would replace the CPT box, but be an autopilot that could be connected to a plotter I’d buy it.
I don’t think I’m alone either, the CPT drive has plenty of power and speed for me without all the complexity and power drain of a below decks autopilot, plus the 5 min change out to a back up one.
It’s only draw back is that it’s just a simple heading hold autopilot.

I think there would be a market for it, I wonder why CPT doesn’t do this?

a64,
Seriously look at the pypilot, it does exactly what you are asking. Don't be fooled by the low price or the small package, it is cutting edge technology, works really well and can be hooked up to a plotter to do even more.
We do run a below deck hydraulic pump and will say the energy use is miserly. Can only imagine that a wheel driven electric motor would even be more efficient. A wheel pilot could be a good back up to a below deck AP.
Been using it for a couple of years now and very satisfied w/the performance of the pypilot. With the super low price of the pypilot components its easy to carry back up brains and motor controller as spares (if ever needed) that can be quickly swapped out.


Bill O.

[a64pilot]

I was having a hard time trying to measure how much current my CPT draws because of course it only draws power in pulses when it moves the wheel.
Then I found out is less than a half amp.
http://www.cptautopilot.com/features.php
.4 amps on average, mine I think is less as I have a very small wheel and a Spade rudder. CPT of course doesn’t know wheel size, but as the leverage is much less with a smaller wheel, the forces have to be lower or it would be real hard to turn.

I’d love to buy a plug n play product as opposed to building my own and then cutting into the wires of the CPT and figuring out what does what.

But the CPT being so easy to change out with a spare, and it’s miserly power consumption, if someone made it so that the drive could be driven by controller that would take inputs from a Plotter, I think once word got out they would sell a few.

If I had a cable driven steering system, then I would want a below deck autopilot driving the rudder shaft directly, but as my steering is rack and pinion, and the pinion is the shaft connected to the wheel, it’s exceedingly unlikely that will beak. About the only way it could would be for the rack to break, or the rudder shaft to shear.

[Bill O]

Originally Posted by a64pilot

I was having a hard time trying to measure how much current my CPT draws because of course it only draws power in pulses when it moves the wheel.
Then I found out is less than a half amp.
Features of the CPT Autopilot - CPT Autopilot Inc.
.4 amps on average, mine I think is less as I have a very small wheel and a Spade rudder. CPT of course doesn’t know wheel size, but as the leverage is much less with a smaller wheel, the forces have to be lower or it would be real hard to turn.

I’d love to buy a plug n play product as opposed to building my own and then cutting into the wires of the CPT and figuring out what does what.

But the CPT being so easy to change out with a spare, and it’s miserly power consumption, if someone made it so that the drive could be driven by controller that would take inputs from a Plotter, I think once word got out they would sell a few.

You've hit all the reasons why you have a low power draw and doubt it would change much if you switched out the brains and motor controller.

Don't know if setting up any boxed AP is going to be plug and play but in your case fairly close if you just want to replace the CPT control head w/ a pypilot. The replacement brains would give you at least the same point/shoot AP capability like the CPT and room for expanding the capabilities if you can hook it up to your plotter.

Have no idea what plotter you have so can't tell you what type of connection(s) you would need. The easiest would be a wifi connection to the pypilot. As previously discussed, we use a RPi w/openplotter as our nav station plotter. With all the info coming from the plotter, we can set the AP to compass, gps (single point/routes) and wind modes.

The efficiency of our below deck pump is very good/excellent and we can monitor power consumption w/the built in pypilot software. Along w/our added rudder angle indicator (optional), we can adjust the sails to be even more efficient w/the AP power.
I'm not a computer genius by any stretch, but setting up the AP was very doable and best of all works well.


Bill O.

[MartinR]

[QUOTE=a64pilot;3026736]
I’d love to buy a plug n play product as opposed to building my own and then cutting into the wires of the CPT and figuring out what does what.
/QUOTE]

The CPT uses little power on its own, and still less when driven by pypilot. Pypilot outputs the consumption data and this averages for me to about 0.2A in a 12V system. Negligible. For a rather big boat.

In my setup I can switch between both controllers and I use both. The pypilot controller is networked and steers by the wind as well as track and heading. It also is remote controlled, so I can steer the boat for example from the bow when anchoring. It can also be controlled from Opencpn at my nav station.

When I am at the wheel, I prefer the simplicity of the CPT control unit, so I am using this for example for approach to port.

The conversion is very simple, but requires some surgery on the CPT drive unit.

[a64pilot]

So where does the Pypilot get wind data?
I have a B&G Zeus. Everything is on the bus, Wind data, GPS, depth etc is all on the NMEA bus.
I’m not trying to reduce electrical draw, frankly it’s not enough to be relevant, but it would be nice to had the features of a “Modern” autopilot without all the excess expense and power consumption of a below decks autopilot, to say nothing of the ease of installation of a back up unit in case of failure.

As is I have to keep adjusting the CPT, it’s a heading hold only and it may drift some but more likely it’s currents etc that cause a couple of degrees of adjustment every hour or so.
It would be nice if it would track to a waypoint, adjusting heading to stay on course.

[Exile]

Originally Posted by a64pilot

So where does the Pypilot get wind data?
I have a B&G Zeus. Everything is on the bus, Wind data, GPS, depth etc is all on the NMEA bus.
I’m not trying to reduce electrical draw, frankly it’s not enough to be relevant, but it would be nice to had the features of a “Modern” autopilot without all the excess expense and power consumption of a below decks autopilot, to say nothing of the ease of installation of a back up unit in case of failure.

As is I have to keep adjusting the CPT, it’s a heading hold only and it may drift some but more likely it’s currents etc that cause a couple of degrees of adjustment every hour or so.
It would be nice if it would track to a waypoint, adjusting heading to stay on course.

Not sure about the Pypilot but I imagine it's similar to the Pelagic which accepts wind data from NMEA 0183 and N2K through a gateway. Not sure about steering to a course/waypt.

[Exile]

Just re-read Bill O.'s post above and apparently the Py is also capable of steering a course/waypt. Making that happen with your CPT might be the challenge.

[Bill O]

Originally Posted by Exile

Just re-read Bill O.'s post above and apparently the Py is also capable of steering a course/waypt. Making that happen with your CPT might be the challenge.

The pypilot gets all the wind, gps, routes/way points, etc data. thru your nav computer. Easiest is to share the data thru a wifi connection (like we do and works well).
The pypilot computer and motor controller would replace the CPT controller to allow the steering to wind, gps (routes, etc) and compass.


Bill O.

[a64pilot]

Originally Posted by Bill O

The pypilot gets all the wind, gps, routes/way points, etc data. thru your nav computer. Easiest is to share the data thru a wifi connection (like we do and works well).
The pypilot computer and motor controller would replace the CPT controller to allow the steering to wind, gps (routes, etc) and compass.


Bill O.

OK, I’m stupid, but what are you calling the Nav computer?

I know it can be done, just frankly I’m not the type anymore to sit down and build one. I had a friend build an ADSB receiver with a Rasberry Pi, I bought one from Garmin. His worked as well as mine did. Mine cost a LOT more.

I guess I’m hoping to get someone to build a box that will connect to an NMEA 2000 bus or plotter and drive the CPT.
I would pay a significant amount of money for that, I assume others would too, if you got the word out.

[hpeer]

Originally Posted by Exile

Just re-read Bill O.'s post above and apparently the Py is also capable of steering a course/waypt. Making that happen with your CPT might be the challenge.

Depends upon what you call “challenge”. It’s 2 wires.

[Bill O]

go back up to #19 and find the hyperlink to the article we wrote about the nav. computer (aka nav. station plotter). It is a RPi running openplotter. Also have an article how we set up our AP

I'm not totally versed on Garmin systems, but sure there are many out there that would know the best way to get the data to the pypilot. There is a also pypilot forum to help w/tech support.


Bill O.

[hpeer]

Originally Posted by a64pilot

OK, I’m stupid, but what are you calling the Nav computer?

I know it can be done, just frankly I’m not the type anymore to sit down and build one. I had a friend build an ADSB receiver with a Rasberry Pi, I bought one from Garmin. His worked as well as mine did. Mine cost a LOT more.

I guess I’m hoping to get someone to build a box that will connect to an NMEA 2000 bus or plotter and drive the CPT.
I would pay a significant amount of money for that, I assume others would too, if you got the word out.

You don’t need NEMA or anything. You connect the 2 (TWO) drive wires to the DC drive motor. Doesn’t matter if the drive motor is a ram, a hydraulic pump, or a CPT.

Now if you want it to work on a “plotter” you need to ask someone else but I think right now it just works with OpenCPN. That project is a bit down on my bucket list.

The Pypilot has a built in gyro compass, that seems to working inside my steel boat. I can’t get my damn binnical compass to work, or the iPhone compass. It’s the only compass I’ve seen that seems to work on my boat.

It also has a USB port for the GPS. You plug a computer hockey puck antenna into it and it works. I don’t know about the wind instrument, I guess it would need to sent sentences as the GPS does and tie in through the USB.

THE PyPilot also has a native wireless link. You can use an iPhone or computer to manage the AP that way. So perhaps a wind vane with a wifi hub could connect and send direction data wirelessly.

Sean also provides a little key fob remote to make course corrections.

Hope this helps.

[Exile]

Originally Posted by hpeer

Depends upon what you call “challenge”. It’s 2 wires.

I was thinking of Bill O's comment about doing some "surgery" to the CPT controller. I probably misunderstood.

[hpeer]

Originally Posted by Exile

I was thinking of Bill O's comment about doing some "surgery" to the CPT controller. I probably misunderstood.

The “surgery” is more like removing a splinter, IMHO.

The drive connection is 2 wires: motor spin direction comes from the polarity of the wires. The AP reverses polarity to reverse motor spin direction. How hard the unit turns is determined by the amount of current supplied. Then there is how long it is supplied. But it matters not which controller (CPT, PyPilot, Pelagic) or which drive unit (CPT, ram, hydraulic motor) they all work the same.

I might be over reaching, there are probably units that work differently, but this is common amongst the units we are discussing here.

Disagreement? Questions?