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Author Topic: Building a board computer for my ship  (Read 1850 times)

PetrOs

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Building a board computer for my ship
« on: June 28, 2018, 10:44:30 am »

I am in progress of rebuilding my Bristol trawler (to a russian pr. 574 trawler in about 1/30), and also in progress of building Mountfleet models Sealight. Both are planned to have lots of functions. As I only have a 10 ch FS-i6 RC, and want to keep costs down, I decided to design and build a "board computer" myself.


Goal: As many additional data channels (switch or proportional) as possible, out to the longest range. Preferrably with telemetry data.



At first, sender. I decided to use Arduino Mega 2560 as a sender computer. It will be housed as additional box screwed to my sender's handle. 16 analog inputs will be used by 6 mini joysticks and 4 potentiometers. (or 5 joysticks/6potentiometers). Also, several 3-position switches and push buttons would be there. I would use an I2C display for telemetry display. For communication, I will be using HC-12 433Mhz protocol. With range of around 1500 meters outdoors, it is more then enough. As the data would be non-critical (boom movement, projector servo, sound, anchor), 9600 baud would probably be enough (I could use higher rate but at cost of range). HC-12 would be driven by hardware serial interface.




On the receiver side:
I am going to use Orange Pi Zero and a few Arduino Pro Mini. A very small quadcore Cortex A7 1.2 Ghz processor with 256 Mb memory, most likely with Armbian running. In idle it takes around 250 mah, comparable with my FPV camera. Internal communication is over I2C.


Pro Mini 1 - interacting with IBUS from my receiver. Sending regular channel data to Pi, feeding telemetry into Flysky system. Probably controlling powerloads over MOSFETs. Such power loads are bilge pump, fan for selfmade smoke generator, etc.


Pro Mini 2+ or PCA9685 - Servo controller for acting servos.


OrangePi - main thing. It shares following:
- Sound operation. Different horns, speed-proportional sounds, background sound, radio effect, morse transmissions...
- HC-12 communication, data aggregation of RC and HC-12 data, actuating PCA9685s.
- XML based config for all actions













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Hellmut1956

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Re: Building a board computer for my ship
« Reply #1 on: August 20, 2018, 09:35:00 pm »

In general anyone of those small microcontroller boards are fine. They all offer the interface called I2C. So if you want many functions the following board I can recommend:





This board I purchased from Aliexpress, here the link! This board called:


PCA9685 16 Channel 12-bit PWM/Servo Driver-I2C interface Module
[/size]
[font=open sans, arial, helvetica, sans-serif, simsun, 宋体][/size]You can connect, if I remember correctly up to 8 of this boards to a single I2C bus that just requires 2 pins of your computer board. Each board offers you 16 PWM channels. You can there for drive any servo this way. I use it to support 8 color controlable RGB LEDs, each with 3 pins to control the intensity of the 3 colors in the LED by using PWM to control the current flowing. So for my application I use 2 of this boards to have those 8 * 3 = 24 pins of the 8 LEDs.[/font]

[font=open sans, arial, helvetica, sans-serif, simsun, 宋体]
If you use an RaspBerry Pi ZERO W which has Wifi and Bluetooth you can communicate with your model by WiFi. So if your transmitter has WiFi. You are done! If you look a bit around with google you will find Raspberry Pi in a case with display. If you put this in your own case you can add 2 sticks as you usually have on an RC transmitter. Additionally you can add as many of any kind of switch or proportional rotation nob.[/font]

[font=open sans, arial, helvetica, sans-serif, simsun, 宋体]
But then you can really benefit from the 2.4 GHz communication which does not know about channels. It just offers a bidirectional serial link over radio waves. So if you use a byte you could have i.e. 256 functions. If you use a 16 bit word you can have 64k functions. Dependent on how much effort you want to invest:[/font]

[font=open sans, arial, helvetica, sans-serif, simsun, 宋体]
You could use any display as used in the PCs. With the RaspBerry Pi you can connect it directly to the board. As you have the Linux OS you can have the Raspi ZERO W desktop GUI to appear in a window on you ubuntu  linux Raspi![/font]





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Best regards Hellmut

C-3PO

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Re: Building a board computer for my ship
« Reply #2 on: August 21, 2018, 07:23:56 am »

Lots of relevant info and like minded model boat / microprocessor users


http://rcarduino.freeforums.net/


regards
C-3PO
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I think it's the way I have learnt most of my stuff - getting very stuck first...
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