Hey all,
I'm currently in the process of building my first ROV. I have absolutely NO previous knowledge of electronics, ROVs, or robotics in any way, shape or form. So far, it's been quite a challenge. I spent the last couple of months researching as much as I could, and I'm beginning to get a handle on things, but I still have some questions that I can't seem to figure out the answer to on my own, so I'm hoping this great community can help.
I'm planning on using three brushless motors, 2 for forward/reverse and one for surface/dive. I will be using one reversible ESC for every motor, and a servo tester to control the motors as I don't want to purchase an RC controller, and I don't want to use an arduino or anything similar.
Right now, the only way I can think that this would work is if I have two servo testers controlling two motors, and basically driving the ROV like a tank, use the left motor controller to turn right, and vice versa for left; use both at the same time to go forward/reverse. My question is this: is there any way that I can wire the servo testers in a way where I can use one servo tester for forward/reverse, and one to turn left right?
Like I said, this is all completely new to me and I'm still trying to wrap my head around it, so I appreciate any help. Thanks!
First-time ROV questions
Re: First-time ROV questions
Hi odics
Have not used a servo tester before, and do not know the circuitry of such, but would say no, rewiring will not help. If you wanted to/had a bit of time to invest in learning simple microcontroller programming, and a little bit more about basic electronics, then the a micro could replace the 3 servo testers and do some basic maths to get the right signals to do what you want. Only a few lines of programming. Easier than it sounds.
However, there is a much simpler solution if you want a single joystick to turn both pots (potentiometers/variable resistor/knobs). Use 3 bevel gears (see pic attached), the centre one with the stick attached at right angles, the pots on the outer gears. This is what I would have done before getting into microcontrollers.
Just have to make a simple support or box around the gears to hold them together, and swap outer 2 wires on one of the pots. Hope this helps
Have not used a servo tester before, and do not know the circuitry of such, but would say no, rewiring will not help. If you wanted to/had a bit of time to invest in learning simple microcontroller programming, and a little bit more about basic electronics, then the a micro could replace the 3 servo testers and do some basic maths to get the right signals to do what you want. Only a few lines of programming. Easier than it sounds.
However, there is a much simpler solution if you want a single joystick to turn both pots (potentiometers/variable resistor/knobs). Use 3 bevel gears (see pic attached), the centre one with the stick attached at right angles, the pots on the outer gears. This is what I would have done before getting into microcontrollers.
Just have to make a simple support or box around the gears to hold them together, and swap outer 2 wires on one of the pots. Hope this helps
- Attachments
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- 3 bevel gears.JPG (81 KiB) Viewed 2885 times
Re: First-time ROV questions
Yeah, I figured some sort of controller would be probably be necessary, but I'm trying to avoid that unless I absolutely have to go that route.
As for the joystick, I have a three-axis joystick (one pot for every axis) that I was planning on using. I was going to just solder out the pots on the servo controllers and use the joystick, which would work for just forward/reverse, but I'm not sure how to also do left/right. The third axis (twisting the handle) would control the up/down thruster.
As for the joystick, I have a three-axis joystick (one pot for every axis) that I was planning on using. I was going to just solder out the pots on the servo controllers and use the joystick, which would work for just forward/reverse, but I'm not sure how to also do left/right. The third axis (twisting the handle) would control the up/down thruster.
Re: First-time ROV questions
OK. If you are determined to use the 3-axis joystick, then there is another mechanical solution, but it involves using 2 servos in your control box, plus another two servo testers. Also, depending on the design of the servo testers, the joystick pots may have to be same or similar value of resistance ie 5k, 10k as the tester pots
I can upload a sketch if you like or you can do a search for elevon or flaperon mixing. This has been done for years with delta wing/flying wing planes before mixing was available in the transmitters like it is today. You would be connecting the moveable servo to your servo testers instead of the flaps...
I can upload a sketch if you like or you can do a search for elevon or flaperon mixing. This has been done for years with delta wing/flying wing planes before mixing was available in the transmitters like it is today. You would be connecting the moveable servo to your servo testers instead of the flaps...
Re: First-time ROV questions
Well, I broke down and ordered an Arduino Uno. I was trying to keep things as simple as possible, but for some reason these projects have a tendency to snowball into something a little more elaborate than what I originally had in mind. I don't think the Arduino will be too complicated to figure out, though.
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KR2_Diving
- Posts: 391
- Joined: Aug 30th, 2012, 11:43 am
- Location: Currently: NW Suburbs of Chicago. Originally: NE Wisconsin
Re: First-time ROV questions
Congrats on the Arduino purchase! You will not regret it!
If you are just starting out with Arduino, I found this book to be the best for an intro! To this day I still refer back to this!
You can find it online everywhere!
I also highly recommend the Arduino reference website and forum! Chances are someone out there has tried doing what you want to do, and they have posted some notes about it online!
Even a simple search in google often provides the answer you are looking for. For example, "connecting a playstation controller to an arduino" will return all the data you will ever need!
Last but not least, there are quite a few of us on here that are playing with the little blue boards as well, and I know the group here has been very helpful!
Best of Luck!
Ryan
"KR2_Diving"
If you are just starting out with Arduino, I found this book to be the best for an intro! To this day I still refer back to this!
You can find it online everywhere!
I also highly recommend the Arduino reference website and forum! Chances are someone out there has tried doing what you want to do, and they have posted some notes about it online!
Even a simple search in google often provides the answer you are looking for. For example, "connecting a playstation controller to an arduino" will return all the data you will ever need!
Last but not least, there are quite a few of us on here that are playing with the little blue boards as well, and I know the group here has been very helpful!
Best of Luck!
Ryan
"KR2_Diving"
Re: First-time ROV questions
That's good news odics. A suggestion for rapid results:
1. Get a simple program working first, something like flashing an LED. This will familiarise you with getting from a couple of lines of programming on the screen to actually doing something in hardware in the"real world". Change some variables and see what happens.
2. Look for other people's programs used for reading a potentiometer and getting a number into a variable from the pot's position. Also look for programs that show you how to create the PWM signal needed to run the servo/speed control.
3 Identify and learn about the commands that have been used in these programs
Be prepared for a great sense of achievement when you get the 3 motors doing what you want from the 3-axis joystick!!
If you have a servo handy then using that in place of the speed control will simplify the programming process. Once you have control over the servo, unplug it and plugin in the ESCs
1. Get a simple program working first, something like flashing an LED. This will familiarise you with getting from a couple of lines of programming on the screen to actually doing something in hardware in the"real world". Change some variables and see what happens.
2. Look for other people's programs used for reading a potentiometer and getting a number into a variable from the pot's position. Also look for programs that show you how to create the PWM signal needed to run the servo/speed control.
3 Identify and learn about the commands that have been used in these programs
Be prepared for a great sense of achievement when you get the 3 motors doing what you want from the 3-axis joystick!!
If you have a servo handy then using that in place of the speed control will simplify the programming process. Once you have control over the servo, unplug it and plugin in the ESCs