I'm struggling to see the catch? I've just bought a hextronik MG14 for £9:-

Voltage 4.8V ~ 7.2V
Gears Metal
Speed 60° in 0.11sec
Model MG14
Weight 14gr
Torque 2.5kg



Whereas the "dream servo" seems much higher specced for only a pound more at £10!

Voltage 4.8V ~ 7.2V
Gears Metal
Speed 60° in 0.16sec
Model FS5113R
Weight 58 gr
Torque 13.2kg/cm

Thanks ...

Would you guys mind clarifying this AVR/socket thing?

if it is what I think it is - I like the sound of it.

I am having a massive faff with my tangle of wires surrounding my arduino project because I can't re-program the arduino from where it sits due to the length of the USB cable so I am having to unplug about 20 cables when I need to take the arduino to the computer. Nightmare!

Who is interested in seeing a video of the end result of their help?

There are plenty of sites on the web showing how to convert a servo to continuous rotation, so you can just spin the servo until the cord is pulled as far as you want it.

oh my - but I had understood this wasn't a win win situation and my servo would lose its intelligence if I did so. For instance, I imagine I would lose any ability to be precise  - and this is important for my application. I need it to move the cord 100mm, then move the cord back to the original position (cord is sprung).

My current question is how do I know how far a given servo is supposed to be able to move?

Final question on this subject - how do I know how far a servo is supposed to be able to move?

I have the SM-S2309B but I can't see this info in the datasheet.

THANKS

A linear actuator?

Thanks - good tech - but far too expensive for my purposes.

L = 10cm
Rot = 180 degrees
therefore circumference = 20cm
diameter = 20 / Pi = 6.37cm
So you attach a capstan head of 6.37cm diameter to your servo and when it turns 180 degrees it pulls a cord 10cm
And if your servo isn't man enough for the job then you get a more powerful servo
viola

Who da man?!?! (You da man)

I'm looking to find a way to pull a cord 10cm. I can say why if anyone's interested.

I have a servo .

But the (not even!) 180° movement it produces won't produce this degree of movement.

So...

1) continuous rotation hobby servo  - not a good idea as doesn't given any positional feedback? Or?
2) winch servo - is this the same as a continuous rotation hobby servo? If not maybe this is the answer?
3) 360° servo? is this the same as a continuous rotation hobby servo? If not maybe this is the answer?
4) DC motor - not a good idea as is essentially a continuous rotation hobby servo?
5) adding a long arm to the hobby servo - doubt the H.S. has the pluck for this?!
6) 'bigger' hobby servo - this wouldn't give me any more 'pull' (right?) but might tolerate a longer arm?
7) something else I haven't thought of


Would welcome your help/feedback.

THANKS

I've upped my code to pastebin as it was getting a bit unwieldy to post here.

I wonder if someone would mind taking a look?

Basically my LEDs are no longer working. The servo action works and the serial prints work but the LED does not light.

It's not my wiring because I've tried "blink without delay" and that works fine.

I've renamed some of my variables and I'm wondering if that's what's done it - but I can't spot the error myself this time.

Oddly - on my arduino mega, (at least) digital pins 53 and 51 are on even though I haven't told them to be on anywhere. Is there a list of such pins? Perhaps they are double up as pull ups for an analog pin? If not I'm lost as to why this is the case. 42 seemed 'free' and as a result I'm using it.

Thank you!

Hi all

Trying to figure out why

  digitalWrite(14 + MyAnalogPin, HIGH);

makes my project work...

but   digitalWrite(MyAnalogPin, HIGH);

does not?

THANKS

PS - don't disconnect the speakers unless you put load resistors (10K maybe) in their places.  Otherwise you will short Vcc directly to GND when a button is pressed.

Do you mean the actual physical speaker unit here? Because if so, I've done exactly that. I've clipped off the speaker. So you say I need to have a 10K resistor between the two dangling wires?

Things work as they are currently configured - but I guess I'm reducing the longevity of the speaker unit at the moment? Or?

I would not take too literally the + and - markings on the speakers. It all depends on the circuit of the amplifier output stage. When you measured the continuity did you do it in both directions? That is swap the leads around to make sure you were not going through a semiconductor PN junction.
However it is possible that the speaker is connected to the +ve rail of the supply and it is pulled down by the output stage. This will result in a square wave type signal.
For what I is worth I don't think your problems are with the 4.5V regulator either, mind you I think it will work just as well off 5V as 4.5V.

So why not connect the speaker - to the arduino input pins and all the grounds together, would that not do it?

Mike - I REALLY value your help. Just wanted to say so.

I didn’t swap the probes when measuring continuity. Will do so when I get home.

Can I clarify? Did you mean to
A)   connect the “speaker–“ to an input pin and tie the vreg ground to the arduino ground?
B)   connect the “speaker–“ to an input pin and tie the speaker + to the arduino ground.

I agree the speakers will work equally well from 5v (I tried it and it works). But I am worried about overloading the ethermega (my Arduino variant) because I would be asking it to provide power for six LEDs, five wireless doorbell receivers, one servo and one ethernet ‘shield’.

[was]

With nothing powered on, use your multimeter to check continuity on each speaker unit

Hi Jim

I think you are right. With nothing powered on there was continuity between vdd and speaker +. There was not continuity between - speaker and GND.

As for what I'm trying to accomplish - I am trying to use wireless doorbells as wireless buttons (i.e. digital inputs).

I'm now wondering how I should wire these up to the Arduino. I had intended to connect the speaker + contacts to digital input pins and tie all of the speaker- to ground - but this is obviously is a no go.

How would you guys do this?

THANKS

Random thought , whats the output of the Walwart ?

It's rated at 9v and 1A.

I humbly suspect that the vreg is not the issue. I think I can get a usable reading from the configuration I described earlier but two things worry me 1) what happens if I need to tie new grounds together 2) I have now departed from a place where I understood why things worked.

you may even try a actual picture it may be easyer to just find a walwart that is 4.5v

I will post an actual picture but it sounded/sounds to me like JimG was on to something!

As for finding a wall wart that is 4.5v, that's what I thought. Then I found that a wall wart for 4.5v can output +/- roughly 3v in either direction! Hence the vreg. I don't think the problem lies in my vreg, though.