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Pypilot for dummies
#21
Sorry should have mentioned: this is still work in progress. What's there are some notes. Haven't figured it out myself yet ?.
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#22
I’ve worked through the steps until step 6, at which point there is an Arduino connected to a Raspberry Pi (3 or 4) via USB. This is shown in the first photo in this section.

Are there operational systems where a motor controller is connected directly to the raspberry Pi (3 or 4)?

This is where I end up by the end of step 9 before Tinypilot is introduced.

Tinypilot provides a simple standalone autohelm.
The Pypilot software is part of the Tinypilot software. Tinypilot will not run on a Pi (3 or 4).
Tinypilot software is intended to be used with a Pi zero W but does use the motor controller previously discussed.

Out of interest which was developed first? Tinypilot or Pypilot as part of OpenPlotter / OpenCPN (Im happy if someone would explain the difference between these packages)

Personally having Tinypilot at step 1 makes more sense as I'm familiar with a Tiller Pilot. This stands regardless of the historical order of development. That way you start simple and build up to the whole plotter package. Seems better given that this started as a Dummies guide. What do others think?

Although Ive read the following steps I would like to get these questions clear in my head first.
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#23
pypilot was developed on tinypilot since the beginning and I continue to develop on the tinypilot platform, but since pypilot is very portable, it works on most linux systems, but laptops for example can't run rtimulib2, and without certain dependencies various parts of pypilot are disabled, but unlike many compiled programs certain missing libraries does not prevent it from working at all.
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#24
(2021-04-19, 07:58 AM)ironman Wrote: I think this is my cue for building up a workbook page with all information that can be found on this forum on what all those parameters mean.


I just trawled through a number of settings and collated from the forum and the code what I could find about them; see https://github.com/pypilotWorkbook/workb...parameters. The selection of settings are those that are stored in pypilot.conf; some are blatantly obvious and I've already started to thin out the list. Feedback welcome, as always!
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#25
I got some questions about the HAT and realized I left that section in the workbook still unfinished. So I updated that section to the best of my understanding. Feedback welcome!

https://github.com/pypilot/workbook/wiki...-interface
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#26
Hi Ironman!

I have read through the Workbook that you wrote. In Step #14 you describe the Pypilot motor controller that I bought at Sean's Web store (see photo attached).    

From my modest understanding, I gather that I should attach 12V to 2 wires which says "Motor". Or, is it the motor that is to be attached there?

Next to this white wire,  there is another thick white wire, with 3 small wires coming out of it: red, yellow, and black. This says "End stops" on the motor controller. What do I do about them?

Next is another thick white color wire coming out of the motor controller. In the photo, it has a red tape at the beginning of it. There are 4 wires coming out of it, going to Raspberry hat that I purchased. I suppose they are 1) VCC, 2) GND, 3) Rx, 4)Tx wires which you describe in your workbook, Step #14.

In addition, there is a black colored thick wire coming out of the Motor controller. In the controller, it says "Rudder". What do I do about these 3 wires? 

In addition, Sean mailed me a thick white wire that has something that looks like a temperature sensor attached to it. I suppose it should go on top of the motor controlling the rudder. Is that right? Where is it to be attached (2 wires, red and black)? 

"Final" question: I bought a windshield wiper motor, as suggested by Sean. I see that there are 4 places where I can attach wires (see photo). How is this thing to be controlled by the Motor controller?     

thanks for reply,

Gennady
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#27
Please only attach 12v power to the red and black screws. anywhere else can damage the controller.
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#28
You attach the 12V to the red screw and 0V to the black one.

The end switches are end-of -travel switches that you should fabricate in such a way that they make contact when the motor (and rudder) are almost in their utmost positions. One switch goes to black and yellow, the other switch to black and red. Which switch goes to what end you have to find out for yourself. If the switch makes contact, the motor should stop immediately from going into the direction of the switch. If you don't attach switches, the motor will continue running at the end of its travel and that might damage your hardware. However, electric motors draw much more current when they are mechanically 'arrested' and the motor controller will sense this increased current and stop. But this happens after the fact. Better is to implement switches.

The rudder cable goes to a rudder angle sensor. You could fabricate that yourself, it is a simple potentiometer, but they are also commercially available. The rudder angle sensor tells the motor controller, and pypilot, what position the rudder is in. This serves two purposes: 1) with a rudder angle sensor, pypilot can sense that the rudder is on either end of its travel and stop the motor. If you have a rudder angle sensor, you might omit the end of travel switches. 2) with a rudder angle sensor, pypilot can steer better, in theory. That sounds silly, but for a long time pypilot has been steering excellently without knowing exactly what position the rudder was in. Recently, a new steering algorithm had been added to pypilot ('absolute') which makes use of  the rudder position. I have not used it yet.

Both end switches and rudder sensor are quite fidgety to build. Pypilot will run without them.

The temperature sensor should indeed be attached to the motor, typically to the metal housing, in such a way that when the motor runs hot, pypilot can switch it off. If there is no cable coming from the motor controller box you have to locate the contacts on the motor controller printed circuit board and solder them on. Reading in between the lines of your questions, I'd postpone that until you are more familiar with the electronics. Pypilot can run without.

A windshield washer motor typically has 12V, slow, fast and 0V. The 12V is to allow the motor to return to its home position, and you don't need that one. The 0V is quite often black. You need to attach the motor (green screws) to the 0V and to one of the 3 others. These are powerful motors and might spin off your workbench, dragging all electronics with them. Clamp it down!
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