Halloween project

Please someone anyone help me.
I apologize in advance for, bad grammar, punctuation. And the long book of a post but I’m trying to explain my vision without confusing everyone to much with that being said....

I’m trying to make a project from scratch at a fraction of the cost of the real thing. I’m super new to arduino and this is my first post ever on any real forum

Also, With that being said. I’m trying to make a harvester of souls I know stupid right. There 300 dollars without tax and no fog machine app about 400 total at a store and I’m trying to make it more controllable and at about half the cost.

Link for hopefully understanding better what I’m about to go on about lol

I want to make the arms be able to move and the head to be able to move off of a control just like the one in the video with something like a potentiometer or any way really, but I’m trying to make it wireless if possible with a rf24 board. I originally purchased a 20kg servo and arduino unos thinking that the 20kg servo would be enough to lift the arms if I put a screw in the pvc and connected the servo to it with wire. But the servo can barley lift a 4lb hammer of the ground at about an inch away from it arm. I’m using a 9v battery to power the servo, should I try a diffrent power source or scrap the servo idea and move on. I can use a servo to move the head it will have more then enough force for that so no worry’s who it that, but the arms are what’s making me scratch my head.... the arms are made of pvc and rotate like a pulley With a shaft that rotates, with all the weight being on the one side. (where the arms extend) it doesn’t require a lot of force to rotate and roll the arms up by hand currently and I don’t have a way of measuring the force needed to rotate it up. all that’s getting put onto it after I figure it out is a foam head and stuffing in a small kids nightgowns so it wouldn't be much more weight then it is now. But wats my best bet to try to lift the arms. What I’m thinking off doing is attaching a cable to the shaft wrapping it a few times and maybe putting it on a stepper motor so it can rotate and pull the cable lifting the arms it only needs to move the shaft about 1 inch or so so I wanna use a stepper motor that I can program to lift up the arms hold position and lower to a resting state. Where all the force will be off the motor. I’m not sure what motor to go with or what way to measure how much weight it will be rotating and I’m also having a hard time finding code to control the servo and stepper on the same board wirelessly with potentiometer or any way really I just need them to move and hold positions. Any idea or help sorry I’m new to anything with forums and I’ve need not been able to find stuff on goggle that works for me and I’m hoping I can get some help if you need pictures of the skeleton of my project to make more sense of it all I can post a video or picture. Sorry if this is complicated and hard to follow I’m frustrated and trying to get this done ASAP thanks anyone for taking there tome to help me I appreciate it more then you will ever know

vuriz:
I apologize in advance for, bad grammar, punctuation.

It's the punctuation, or lack of it, that is the problem. You have written a very long paragraph that includes several different thoughts with no gaps between them. Look how a little white space makes it much easier to read

I want to make the arms be able to move and the head to be able to move off of a control just like the one in the video with something like a potentiometer or any way really, but I'm trying to make it wireless if possible with a rf24 board.

I originally purchased a 20kg servo and arduino unos thinking that the 20kg servo would be enough to lift the arms if I put a screw in the pvc and connected the servo to it with wire. But the servo can barley lift a 4lb hammer of the ground at about an inch away from it arm.

I'm using a 9v battery to power the servo, should I try a diffrent power source or scrap the servo idea and move on. I can use a servo to move the head it will have more then enough force for that so no worry's who it that, but the arms are what's making me scratch my head....

the arms are made of pvc and rotate like a pulley With a shaft that rotates, with all the weight being on the one side. (where the arms extend) it doesn't require a lot of force to rotate and roll the arms up by hand currently and I don't have a way of measuring the force needed to rotate it up.

all that's getting put onto it after I figure it out is a foam head and stuffing in a small kids nightgowns so it wouldn't be much more weight then it is now.

But wats my best bet to try to lift the arms. What I'm thinking off doing is attaching a cable to the shaft wrapping it a few times and maybe putting it on a stepper motor so it can rotate and pull the cable lifting the arms

it only needs to move the shaft about 1 inch or so so

I wanna use a stepper motor that I can program to lift up the arms hold position and lower to a resting state. Where all the force will be off the motor.

I'm not sure what motor to go with or what way to measure how much weight it will be rotating

and I'm also having a hard time finding code to control the servo and stepper on the same board wirelessly with potentiometer or any way really I just need them to move and hold positions.

Any idea or help sorry I'm new to anything with forums and I've need not been able to find stuff on goggle that works for me and I'm hoping I can get some help

if you need pictures of the skeleton of my project to make more sense of it all I can post a video or picture.

Sorry if this is complicated and hard to follow I'm frustrated and trying to get this done ASAP thanks anyone for taking there tome to help me I appreciate it more then you will ever know

A good test of readability is to read your text aloud to yourself.

...R

You have not told us what experience you have with Arduino programming - if this is your first project then it may be a bit too ambitious.

You say you are powering the servo with a 9v battery and that raises two concerns. First is whether the servo is designed for a 9v power supply - many of them are designed for a max of 6v. Please post a link to the datasheet for your servo.

if the servo is designed to work with 9v then the other concern is what sort of 9v battery are you using. The little PP3 smoke alarm batteries are completely unsuitable for powering a motor - they can't provide enough current.

If you can get it to work it will be much easier to implement your project using servos rather than stepper motors.

There is a simple method for measuring torque in my Stepper Motor Basics which will be just as useful for figuring out the load on a servo.

Adding a counterweight to an arm can greatly reduce the force that needs to be lifted by the servo.

...R

https://www.amazon.com/gp/aw/d/B07TKTQ2NZ?psc=1&ref=ppx_pop_mob_b_asin_title

That’s the servos I purchased. I’m not sure where the data sheet is for these, but maybe that link we’ll help.

I’ve got some experience with arduino I’ve been watching tons of videos about it and have messed with the bored before. Trying to learn about it.

So far I have the board wirelessly communicating and is able to move the servo back and forth, but the servo is stalling trying to even lift a 4lb hammer and I believe that’s from not using the correct power for the servo. Your correct I’m using the fire alarm style 9v battery

I’m hope the servo will maybe still work. I could mod the servo to spin 360 degrees both ways and Program that in the code to pull the arms up and down like a stepper motor would. Even if I have to put it on some pulleys

Would you like some pictures of the project for a better understanding on what I’m babbling about

Robin.
I honestly didn’t even think about a counter weight like an elavator works right ? That might really easy the load on the servo then..

Your Amazon link clearly states that the voltage range for the servo is 5v to 6.8v so it's just as well you were using a puny 9v battery or you might have destroyed your expensive servo.

Large servos like that will need a lot of current - perhaps 3 to 5 amps. Unfortunately the specs rarely list the required current. Try a pack of 5 x AA NiMh rechargeable cells (6.8v). I doubt if a pack of 4 x AA alkaline cells (6v) could provide enough current, but would be worth trying if you have some.

If you want your Halloween prop to operate for several hours a 6v mains power supply than can provide at least 5 amps would be best. Having too many amps does no harm but an under-spec power supply will overheat and might cause a fire.

Also, make sure that the load on the servo is never so great that it can force the unpowered servo to move - i.e. to overcome the friction in the gears. Servos are not designed to hold position using power for long periods.

...R

Understood robin,
I maybe read it wrong thought it was rated for 8.6v I think I’m gonna go with a counter weight option so when the servo is off it will hold still on it’s on or close to it.

For the head moving I’m planing on using a servo for the head as well. Same size servo could running it off the board work for it. It will only be moving a styrofoam head with little to no weight. Or should I get a power supply that will power both servos with plenty of amps for them. I’m not sure I can find a 6v power supply with 10 amps but I may be able to.

if not would these batteries do the job 5 for each servo Amazon.com

Also Robin.
I’m thinking of scarping the wireless idea unless I can get them working properly right now if I turn the potentiometer to fast the servo stops responding the orange light on the board comes on and resets where the potentiometer is positioned at according to the potentiometer and then will work again. only if turn the potentiometer slowly does the servo move correctly idk what could be causing it. But I heard the rf24 board needs a capacitor or a module to run smoothly or correctly since a lot of people have issues getting the to run smoothly any idea on this ?

Referring to Reply #6 ...

I suspect a much smaller servo would be sufficient for moving the head and, if so, then the one power supply would probably be OK for both. I would certainly try that before investing in a second power supply.

But make sure to check the voltage range for both servos and make sure that the single power supply is suitable for the servo with the lowest maximum voltage.

If that means using a lower voltage than the max for the big servo and it that proves not to deliver enough power from the big servo then that would be a reason for a second power supply.

You will need to experiment.

...R

Referring to Reply #7 ...

Please allow time to get an answer before making another Post, or make sure that you have included all you want to say in the Post so you don't need a second one immediately after.

If the project will work with manual control with a potentiometer then I see no reason why it won't work with wireless control using a pair of nRF24 modules.

When you move the potentiometer fast you are probably increasing the power demanded by the servo beyond what your battery can provide. I don't know what orange light you refer to.

...R
Simple nRF24L01+ Tutorial