Dear RobotShop and all robot gurus.
I hope that it is right place to find help. I’m absolutely new to robots; however I’m familiar with digital electronics, programming etc.
I am in the beginning with my project – I mean very beginning. The idea was born after I found RobotShop site.
My project is for my sailboat – not model but real one.
I know that a couple things could be done using robotshop parts.
I like to have ruder indicator – very simple. Potentiometer as a sensor and servo as indicator. Wired – distance about 20ft, 12V
Second part is little more complicated. All radio controlled. 12V
I like to control engine throttle – torque about 5-8 Kg/cm. Linear potentiometer + servo?
I like to control gearbox – switch Forward/Neutral/Reverse – torque about 15Kg/cm switch + servo?
I like to control Bow thruster – momentary switch Left/Right - switch + Relay?
I like to control hydraulic steering system - momentary switch Left/Right - switch + Relay
I like to control anchor winch - momentary switch Up/Down - switch + Relay
I’ve checked – what is offered by RobotShop – unfortunately there is too much information, and I’m not ready to make right selection.
I’m looking for your help to point me to right parts for my projects.
It is going to be first step – I’m sure that I will have more questions in the near future.
Thanks a lot in advance
Hi RobotShop.
Thank you for answer. Of course I can provide more info about the boat.
Yes – my boat is 41’ and is very heavy – because of it I decided to add bow thruster. Now I operate bow thruster by momentary switch leashed on long wire. I have two helms – one outside and one inside where I have to operate – sometimes I have to be on deck. My idea is to have it RC controlled.
About forces needed to operate throttle and gearbox. I measured it.
Please find attached pdf document with pictures and briefly calculation - link seagoatonline.com/SG%20-%20automation.pdf
Thx again
Amada.
Hi RobotShop;
Thank for suggestions.
First about throttle and gearbox; Please explain me why linear actuator but not servo?
The advantage of servo is that I can force it manually to change position. In emergency situation I do not have to disconnect servo – just manually force entire system.
About ruder position indicator; I know that my picture is not very clear, but idea is very simple.
I have hydraulic steering system with two helms. Both helms work independently, what means when I’m turning one wheel – second one doesn’t move. Let say on one station I put ruder to left, now from another station I put ruder to the right. Because of it I can’t add mark to the steering wheel indicates “neutral” position – because it changes continuously. It is very hard to see ruder position from the boat. What I did – I extended ruder shaft into the cockpit. On the top end of shaft I mounted 10 inches in diameter plate with red mark parallel to the boat axis when ruder is in zero position. Now when rudder changed position by any of helm – my plate rotated accordingly. The only problem is that I can see that plate only from one helm – in cockpit. I can’t see it from pilothouse helm.
Now my idea was to mount potentiometer on the end of ruder shaft – where now I have my plate.
Magically connect (wired or RC – distance about 18’) this potentiometer (sensor) to typical servo. Servo arm will show me position of the ruder or more correct angle of ruder shaft.
I think that I should start my project with simplest part. I thing that ruder position indicator and set of relays will be the first stage of my project. Throttle and gearbox will be stage two.
Hi;
I like to start with something simple – what I said before – with ruder indicator.
I like to use Manual Servo Controller (Assembled) Product code: RB-Ima-29
Just three question:
1.What is resistance of potentiometer?
2.Is it linear?
3.Can be operated with 12V?
Or maybe you have different suggestion?
Thx
Amada
Thank you for clarification.
I will try to do that – and I hope that it will work for me.
For the second part for my project I need a little more help from you.
First of all – I am impressed with Arduino Uno. I think that it very flexible system.
I know that I can control relays, motors etc. (analog and digital).
Base on remote control link:
MCU -> Encoder -> Transmitter ------ Receiver -> Decoder -> MCU
I understand that MCU could be Arduino Uno – but – on both sides (transmitter and receiver)
Could you point me to Encoder/Transmitter – Receiver/Decoder what is compatible with Arduino Uno?
One more question - RB-Gws-32 – 4 channels radio control system – can I control relays instead of servos?
Thx
Amada
Hi;
RB-Ima-29 is out of stock now - so probably I will go with Arduino Uno USB Microcontroller.
Just two more question
Voltage for Ardurino is in range 6-12V
What about servos where voltage is not specified?
For Arduino should I find servo specialy for this microcontroler or I can use any standard servo?
Thx
Amada
Thx;
I’m trying to put pieces together.
Q. Servo spec shows running current with no load. What current is going to be with listed load?
How to calculate that?
Hi;
If 12V is OK for RB-Ima-29 my question is:
Does RB-Ima-29 include voltage regulator for servo? in example for Futaba S3004 Standard Servo Motor
Thx
Amada
Welcome to the RobotShop Forum. Can you provide a few additional details about the boat itself? You indicate you have a bow thruster - that is usually only present on boats over 40’ long. Do you plan to control is remotely from shore (i.e. completely unmanned?). The first thing you will need to do is measure the maximum force / torque at each point you want to automate - this is something that cannot be “guessed”. You may need to purchase a force gauge (inexpensive device which uses a spring and gives you a good idea of the force required at a point (for rotating point, simply multiply the force by the distance to get the torque. Note that you need to measure reasonable maximum values and multiply this by a safety factor (for example 25%). Once you get the force values, itemize them there, and ideally include a photo of each point so we can suggest the right technology.
Throttle setup: The best actuator to move 4 inches is a linear actuator, though you need to be careful about the speed - if you want to throttle down fast, the actuator can only move so quickly.
Gearbox setup: Same as above; to move 4", the best choice is a linear actuator.
Switch for anchor: You can replace this with an R/C relay.
Rudder position: hard to tell from the image.
Note that if you use a linear actuator - or any actuator for that matter - it is critical that you include a failsafe which allows you to disconnect/ deactivate the actuator in case of emergency. For example, you used the actuator to move to full throttle, only to find you lose electrical power. The actuator cannot be reversed manually, so you need to be able to pull a pin or something to disconnect the actuator and throttle down manually.
A servo is certainly an option, though you would need to figure out some way of mounting them. The force is already linear, and there are R/C linear servos available. If you can figure out some way of properly mounting the servo, you can certainly keep it as an option. You also need to consider travel distance: if you mount the servo anywhere but at the pivot point, you may need a separate mechanical system to transfer the torque at the right stroke length. It would be very good to draw your potential setup in CAD before actually building it.
If you can find a way to mount the potentiometer, wire it to a microcontroller which then operates a servo, you should be fine. The 18’ distance will depend on the available power - wiring it may or may not work, so you would need to test it.
Almost all transmitter / receiver pairs we offer are compatible with Arduino because the Arduino can handle almost all communication methods. You ca ncertainly control relays using an R/C system. In the Relay and lED controller category, simply look for any that mention R/C.
Most standard hobby servos (Hitec, Futaba, GWS) operate at 4.8V to 6V (don’t go above 6V). There are no servos specifically made for Arduino. You really only need to choose a servo based on the torque it can provide. Be sure to check to see if you need to power the servo separately.
For a servo motor, there may be additional information in the specifications sheet (depends on the manufacturer). Sometimes they list stall torque, and the continuous torque will be about 1/3~1/4 this value. If there is no information, a standard servo tends to consume about 200mA, a 1/4 scale or “Giant” servo can easily consume 500mA+. This value goes up when the servo has to work harder (closer to the rated maximum torque).
