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[Tug-Kenny RIP]

@  Dave
I shall be experimenting today.  Thanks for the looping advice. Understandable that there might be a 'fight back' in the circuits.

@Barrie
I've never seen such cheap  ESC's    

@Malcolm
Just as I suspected.  I thought there might more to it that first envisaged.



Another thought for you all.    What if the motor leads were removed from a servo and run out to the miniature motors in the crane.  Would there be enough micro amps to turn them.  I'm going to try this as well.

Should be a fun day.   At least I'm out of the rain and have the warmth of my soldering iron.   tehe        What a great, friendly intuitive set of club members who like using their heads.   


ken

[inertia]

Another thought for you all.    What if the motor leads were removed from a servo and run out to the miniature motors in the crane.  Would there be enough micro amps to turn them.  I'm going to try this as well.

Ken
There are plenty of articles around telling you how to convert a servo into a speed controller (which is what you're indicating) but the big problem is that servos have a very tight deadband and it's therefore very difficult to stop them at dead centre. I'm also a little concerned that these ESCs might not allow you to run the crane motors sufficiently slowly - but for less than a fiver each I don't suppose there's any harm in having a play with one! If you finish up with some redundant ones then I'm sure Barrie will take them off your hands.........
DM

[John W E]

hi ya Ken
 
Is there any special reason why you want to use speed controllers for controlling the movements on your crane.    Hows about 3 servos, (2 of which could be old ones with the electronics stripped out just leaving the motor and gearing) and the movement converted to complete rotation on these 2 servos.    Then, on the end of the servo drive mechanism a drum made up for to take your cables.   One servo will be for winching the jib up and down; the second servo which is modified for lifting the hook up and down.   What you need is (I think) an ACTion P44 which you will need 2 of, both switchers and programmed for non-latching connect one servo motor to one switcher which controls the jib movement through the servo, the other switcher controls the hook movement up and down.
The 3rd servo, could be say one of them that you purchase that is either a sail winch servo or one that has been modified to work at 180 degrees and this controls the slewing from port to starboard of the crane.   These then will all be fitted to the appropriate channels on your RX and then you will only require 2 speed controllers to control your movement of the vessel back and forwards.
just a thought for you Ken.
 
aye
John

[barriew]

Ken
I'm also a little concerned that these ESCs might not allow you to run the crane motors sufficiently slowly - but for less than a fiver each I don't suppose there's any harm in having a play with one! If you finish up with some redundant ones then I'm sure Barrie will take them off your hands.........
DM

I've used these with servo motors and 140 sizes. I can't speak about very slow running, although I would have thought that servo motors would need to be geared to get sufficient torque for the crane.
Current plans don't call for any more miniature models, and I will shortly have one spare thank you DM. 


Barrie

[malcolmfrary]

Ken
There are plenty of articles around telling you how to convert a servo into a speed controller (which is what you're indicating) but the big problem is that servos have a very tight deadband and it's therefore very difficult to stop them at dead centre. I'm also a little concerned that these ESCs might not allow you to run the crane motors sufficiently slowly - but for less than a fiver each I don't suppose there's any harm in having a play with one! If you finish up with some redundant ones then I'm sure Barrie will take them off your hands.........
DM

The ESCs work very well controlling my yacht winch which is basically a servo motor plus gears minus the original electronics (as stated, the lack of deadband getting on my wick).  The cheapos work well, better than a more sophisticated alternative that had a "soft start/stop" which meant that any precision was impossible.

[Tug-Kenny RIP]

Thanks you all for your advice and notes on the cranes movement.

That problem is already resolved in that I have fitted miniature geared motors to the cranes lifting and pulling of the hook.  There is a geared motor under the deck already connected to the rotation shaft.  All these separate motors need to be controlled by a speed control system.

ken

[Tug-Kenny RIP]

As you may have noticed,  I have brought over my separate thread that was on   'Motors' section, to join this main build thread.  I do apologise for causing you some hassle.

Now it's all together for easier reading and comments.

ken

[Tug-Kenny RIP]

Today was a disaster   

The transmitter had gone flat.  Two servos were faulty and need repairs internally .................   oooh Vicar !!!!!      Torn gears and no plugs.

I have them all set up to get all the channels on my DX7 wired in at the same time.  It was then out with the Expensive Spectrum receiver and  when the R/X had charged we tried binding.  Well that took 35 mins.  Bad connections in my lash up on the bench, but we got there in the end.

After 40 minutes of playing around finding out what lever did what to the servos, the receiver went off.  It was extremely hot the touch and now doesn't work.  So it was out with the orange R/X and away we went on the testing but lost the extra servo control.   

See the line up in the pictures which include the AR7100  R/X  ( £40 worth  !!!!)

One of the servos was my test bed for a continuous rotation by removing things inside and playing with resister values.   Dave, you are correct about the deadband.  The thing keeps turning even when the transmitter is switched off. You can see on the pics that I have adjust pots as well.   I shall not be pursuing this avenue but going over to ESC's for my gentle control idea.

That was my day gone so more tomorrow.   

ken

[Tug-Kenny RIP]

Hiya John

Here is a close up of the winch driving system.. I managed to get some miniature motors and made some small drums. The whole lot fits into the space on the crane and has quite a pulling power.  I'll check the  'amps'  to see if they can be driven by the cheap ESC's mentioned above.

In the piccie they look skew wiff but they levelled out ok.

Cheers

ken

 

[malcolmfrary]

And one of my versions using a butchered servo, mod for continuous rotation, original electronics replaced by one of Actions Pico ESCs.  The box is one of Maplins potting boxes.  From their past record, now that someone has found a use for them, they will probably discontinue them.

[Tug-Kenny RIP]

Very smart and tidy way of doing it.

Todays plan is to experiment with switching wires via radio control.  Wish me luck.

ken

[John W E]

Ken
I tried switching just the signal wires when I was making my show demonstration boxes for ACTion ESCs, but Wombat's cursed earth loops and other oddities cropped up so often that I eventually resorted to switching both the signal and positive lines. It's no big deal if you use DPDT relays (one for each pair of ESCs). You can arrange for one channel to switch three such relays at once.
Pete Keirle - God bless him - actually came up with a PIC program and unit which did the job without relays, but I never got it to work with my test set. I called it Channel Hopper; PMK called it 'Kevin'....................
Come back, Pete - your country needs you 
Dave M

Hi Dave did you get the mark 2 version from dear Peter?
As this one works
Aye
John

[Tug-Kenny RIP]

That's a tidy way of doing it.   

ken

[Brian60]

I have a love hate relationship with electronics. I love dealing with them but hate it when they don't act in the way I envisioned. My present build I have decided instead of doing everything piecemeal. I am going to lay it all out on the bench in its approximate locations and design the wiring/circuitry all at once. Hopefully it will be a tidier solution (and work!)

[ballastanksian]

I have a healthy respect for electric as when it is big, it electroplates you, and when it is small, it can still zap small things like servos and ESCs.

I am still not convinced that Electric is not magic and just dressed up in a variety of boxes and copper tubes wrapped in coloured pastic for the the electricity to pour through:O)

Eventually I will probably have a go at wiring random things together to see how much grey smoke I can make, but for now I am following the plug and play route with units and big instruction sheets (that I promise to read before doing anything:O)

[Tug-Kenny RIP]

That does seem to be a good idea, Brian. I usually try each circuit one at a time and then fit as I go along.  It does become confusing at a later date when you come back to it as you have to work out how you did it in the first place.          Always make a sketch, I guess.

Today's experiment with servos was concluded quite quickly after discovering the output voltage to the motor.  I disconnected the servo motor wires and ran them directly to the 12 volt geared motor in the crane lifting gear.

The servo behaved marvellous under radio control but it moved so slowly, I wondered if it had stopped working.  A quick test with the meter revealed the motor was working on 4 volts  ?????   no good at all.

I then decided to run a speed controller instead so one was tried and it was great.  So it's been decided to fit these instead, so that's the weekend planned out.   

ken

[essex2visuvesi]

Can confirm... these are great little ESCs for the money


If you want one for testing purposes ill sling one in the the post

[Tug-Kenny RIP]

Thanks but that's Ok Garry as I have some in other boats.
Cheers

ken

[malcolmfrary]

Today's experiment with servos was concluded quite quickly after discovering the output voltage to the motor.  I disconnected the servo motor wires and ran them directly to the 12 volt geared motor in the crane lifting gear.

The servo behaved marvellous under radio control but it moved so slowly, I wondered if it had stopped working.  A quick test with the meter revealed the motor was working on 4 volts  ?????   no good at all.

I then decided to run a speed controller instead so one was tried and it was great.  So it's been decided to fit these instead, so that's the weekend planned out.   

ken

A 12 volt motor on the RX supply will run slowly, using the servo electronics it will be running on the same supply as the servo would have got, i.e. 4.8-5 volts less whatever the output transistors drop.  If the motor wanted more current than the board could supply, then the best case is reduced output voltage, the worst case is smoke and smell. 
The speed control would supply from whatever voltage it was being supplied with, as long as the motor doesn't want more and the ESC is being supplied with voltage within its range, everything should be fine. 
If supplying motor power from the RX supply, beware.  The connections in the RX might not be happy with the current load.

[Tug-Kenny RIP]

Yes I have now realised that.  Thank you Malcolm for explaining the details. I bow to your superior knowledge.

I am now using AcTion's speed controllers and they work as expected.  An expensive way to go, but satisfaction guarantied.  Something magical about sitting in a chair and controlling gadgets from a remote box.      

One small niggle is that cranes hook doesn't like lowering due to it's lightness.  Must hook up a grand piano for smooth actions here.   

cheers

ken
 

[Brian60]

re-cast the hook with a bit of lead. Simple to do.

Some fine sand, tamp it down, press your hook into it and tamp it down solid. remove the hook - one mould. A couple bits of lead inside a bean tin, crush the top of the (clean) tin to form a spout. Place on lowish heat on gas stove and wait for lead to melt, then carefully pour into the mould. Being careful not to breathe the lead fumes or indeed get splashed with the hot lead.

Let it cool down and remove the new hook which should add the required wait needed

Of course you can get real fancy and make a two sided mould so that both sides of the hook are duplicated exactly but that is more complicated. Or maybe just cast half the hook twice, and then glue together back to back with superglue. It depends on how much detail you want to include on it.
 

[Umi_Ryuzuki]

Or just add a lead ball to the line, or hook mount.
 


.............

[Netleyned]

Just slide a drilled lead fishing sinker down the hook
line Dont think they are lead but something not as
Nasty. They come in all weights and sizes.
FYI on cranes they are called ponder balls.

Ned

[Tug-Kenny RIP]

You've got me hooked  Umi.   

I did mention that I have part of lead roof wrapped around the string, so I'll go the whole way and make it all out of lead.

Cheer

ken

[Brian60]

I don't want to pee you off Ken but, take a look at this link. I spend my time looking at other boat forums in europe, its easy to do if you paste the address into google, it translates the pages into enough english to understand what they are talking about.

Anyway I was on a German site and came across this link to the Seabex crane......



https://translate.googleusercontent.com/translate_c?depth=1&hl=en&prev=search&rurl=translate.google.co.uk&sl=de&u=http://www.herbundsab-modellbausaetze.de/shop-neuheiten.html&usg=ALkJrhjN86Plh1Z2APE4XC2ZOfXiPBWB0g