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DIY autopilot


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Sorry, wrong Matt, I meant the other matt (I hate these anonymous names). But to address the question, I disagree it's totally unrealistic. Imagine .... as John Lennon sang. A good step along the way would be more power to regulators to rein in superprofits (they could do that via a "secret" process). We saw "democracy" introduced to the west a few centuries ago; they just forgot to give individuals instead of dollars the vote in company structures.

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Oh hang about. A TP10 is a tiller pilot? OK so that is still an OK price, but not what I was referring too. So we are on different pages here. In fact, the Tiller Pilot kind of shows the hole in the price theory you guys are talking about. The Tiller Pilot has everything bar a screen. So of course it should be fairly pricey. But actually it isn't. The Console mounted LCD screen units that drive Helm Pumps/Motors, are horrendously pricey and that is not including the mechanical parts. That was what I was referring to.
I am talking about the Units that are $3K to $5K and on up.

 

You and wheels are in another planet.

I have been in the Electronics game long enough to understand about what goes into a design and I can assure you, it is not that expensive. Although sure, R&D spread out over Units sold will always mean high production numbers like iPhones would always be cheaper than an AP. But digital also means that very little of the internals change and mainly the Software is the part that is upgraded.
 

The leading marine electronics brands spend MILLIONS on R&D, as IT said.

 

There are not that many of them. Many brands are owned by one Company and they share the information across the brands. In fact they brought one big name brand just to get the Digital Broadband Radar technology. That is now in several of their brands.
The Guy that makes the Cruzpro instruments actually makes AP boards for another brand name.
 

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Ok Wheels, below deck pilots start at $1319 incl GST for the NAC-2, or $2300 incl for the NAC-3 that would suit your boat.

There is no such thing as an AP controller for the B&G stuff any more - your Vulcan unit has the required software and function intergrated.

These units are the brains and power control - with all the goodies, compass heading, track, Nav, wind angle, gybe prevention, etc etc . They need an nmea2000 bus to connect to, with a spare T, a rudder feedback unit, a heading sensor and some type of drive (hydraulic or electric) added to operate.

To be fully functional they also need wind instruments, gps input etc etc. Yes, at that point you don't get much change out of 10k for AP, instruments, mfd, etc, whole setup.

Some people want multiple instruments, multiple screens (MFDs), remotes, wifi, stereo control, radar, ais, specialist sounder, and more. It's pretty easy to add up to 30k or more for a complete system.

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Thanks IT. So that is a game changer then and great to hear. You know what I mean surely, that only a few years ago, these AP's were so stupid expensive and this new design from B&G is what I was hoping for. And I still truly believe that the things I have commented about above, that should be making them cheaper, is obviously done just that re the Vulcan. They no longer have to build expensive Electronic designs because so much of it is software based instead with tag on components around a central Hub type idea. Brilliant, great idea, I just need to get back up to speed with what is now available. 
 

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too tall - yep the rudder sensor was my big innovation I'm quite proud of. It resides in the tillerpilot itself and is just a 10 turn poteniometer driven by the ram via 3d printer belts and pullys. That gives me 0-5v depending of the relative position of the ram (and therefore the position of the rudder). Then it's just a case of measuring the signal back at hard port, hard stbd and neutral, entering these into the code and voila - rudder position.

Awesomely simple and cost effective innovation. 3D printing opens so many opportunities for innovation at a DIY level. 

 

Edit. Or did I misread that as to be you used parts from a 3D printer, not made on a 3d printer?

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That's just plain daylight robbery.

 

It's about time we had something to take on the costs of these things. An AP is simply not that expensive to make by the manufacturers. They charge what they do because they can, not due to cost of making. There is not a great deal inside the units and most of the "brains" is inside a Chip. There would be lucky to be maybe $80 worth of parts inside. As IT said, the compasses and Rate Gyro are all solid state now. The old compasses were a bit more expensive due to a lot more manual labor involved, but now the Solid state devices are few bucks if even that.

Fully agree, although they are comparatively low volume products which means everyone wants a larger clip of the ticket. 

Also, there are R&D, support, warranty, distribution, marketing, administration and many other costs you have to figure in too. 

 

I once spent quite a while discussing true cost vrs per item cost manufacturing cost with the owner of a company who design, build and sell globally, hifi products. His take was that for every dollar spent at a manufacturing level to produce a product, that their company, as a low volume manufacturer of higher end goods, would have spent $3.50 on R&D, admin, marketing etc. Then they need to make a profit. So that $1 manufacturing cost turns into $4.50 plus a nett margin, so say, $6. Then distribution costs, and distribution margins, which are apparently around 250% ( This particular company have distributors as opposed to owning their own distribution network ). So that $6 turns into $15. Then retail gross margins are around 200%. Your $1 manufacturing cost is now $30. And no one is making a huge profit along the way, either. 

 

The profit margin of the company I am making an assumption at here ( that was not elaborated on by the owner ) - and to be honest, I suspect that 33% is not high enough being the numbers are fairly small at that end of the chain.

 

But wheels, that $80 can easily turn into a much larger number very easily without it lining pockets. I am absolutely not saying that its right, but with everyone wanting to clip the ticket, things get pretty expensive pretty rapidly.

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Yep they are parts for making a 3d printer that are available direct. Again, the innovation of DIY manufacture of the printer themselves has spawned an industry of people supplying parts for them at very low cost. 

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I used a linear actuator with a built in Pot for position sensing. Had a bit of trouble initially as it had a cheap Chinese knockoff Pot in it which was quite noisy. Luckily, being a typical knockoff, the Pot was identical in its external design to the genuine Vishay one, so was an easy swap out!

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knotme the idea that the world was round was once "ludicrous". You should get out more. BTW are you seriously calling slanty's contribution ludicrous? I'm also guessing you have an idea of how much of our current world was developed in non profit government labs before the crazy drive for privatising everything? I'm afraid too many ppl drink the koolaid these days.

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Yea - the gold standard is actually a hall effect sensor - no physical contact like a pot so much longer life and generally better specd. Was surprised that even modern rudder position sensors are still resistors.

 

Thinking of springing for one of these if the pot gives me trouble:

 

https://www.megatron.de/en/products/hall-effect-multiturn-rotary-encoder/hall-effect-multi-turn-rotary-encoder-hsm22.html

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Rudder feedback

 

I see you can buy bits for that (to measure it???) and the name pops up a lot but what exactly is it and why?

 

It sends a signal back to the computer on exactly where the Rudder is pointing.

The two methods are a Potentiometer, which is a variable resistance and thus sends a varying voltage back. The other method is using the Hall effect sensor, which uses magnetic field position to vary a signal voltage. It's a tad more complex, but is not subject to any mechanical wear and noise like the Potentiometer is.

The feedback info is then used by the computer for speed of movement, max side to side swing and angle to point the rudder.

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correct me if i'm wrong

 

the autopilot can work by turning the rudder until the compass picks up the course change and stops turning the rudder

 

but that's always going to be quite a slow system that will lead to the course being a series of S curves

 

much smoother, better course if the ap brain also has knows what the rudder angle is while course corrections are being made

 

for example, instead of making course corrections until the compass reports them back 

 

it can move the rudder 10? degrees, stop and wait  few seconds for the compass to report back that course is changing

 

then a few seconds later if the course correction still isn't right it can try a 5? degree movement etc

 

a refinement, like having a bigger remote compass module that can be placed well away from engine iron, pitching etc

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Yes erice, this is some of what the Rudder position info does. The speed and amount of movement is also what the "sea state" part of the calculations is providing. In calm conditions, there would be very little need of large/fast swings. Minor movement is all that is needed and of course, that greatly reflects in less power used. Big seas need fast and larger swings of the rudder.
A Compass is just one way of reporting a Boat heading. It can also be done with GPS now. It requires two GPS antennaes positioned a certain distance apart and the difference in info is then calculated to position, heading, speed and so on. Even though GPS can be inaccurate, it doesn't work that way for this. The Computer is looking at the difference between the two received signals and calculates the info from that. So even if thee is an error in the actual position, it does not matter. The result is a very accurate and fast response to changes and a much smoother track when in ruff sea. The down side is the need to have two GPS antennae and having them at a distance apart. It's not a large distance, but it could still be an issue on a Sail boat.

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It's a holiday so you can be forgiven! But I'm guessing a beam of 5m+ will be sufficient!

 

VB is also looking into 3d underwater scanning on these types of sail boats taking advantage of the beam

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