So I really don't know what I'm doing...

Hi, I am looking for some guidance on what I need to be getting in order to complete my project. I'm trying to make a compact thing that has one motor that extends an arm downwards to press and hold a button on an external machine. There also has to be a timer on it that can be measured to 0.01 seconds, and three buttons to add/subtract time, and start the "robot". The time input would have to be sent to a method that would take that exact time as a parameter for extending the arm and holding it in for that time.

I've read around a bit and I think that I can do all of this on an Uno. I have plenty of experience in programming, it's just the hardware aspect of this that I have no idea about. Is it possible to do all of this? I figure I'll have to get some sort of servo motor, but how do I go about attaching that to an arm that would extend outwards? I also have no idea how to wire anything, does all of this sort of just "plug and play", or do I need to solder?

I appreciate any help I get, and sorry if these are basic/stupid questions.

Thanks.

Perfect, thanks. I realize it would be easier to have the button “pressed” electronically rather than mechanically but this button lies on another machine that is not mine, I’m just making this project to be able to interact with one single button on it. It may seem stupid, but there really isn’t any other way to go about it without a machine of my own.

As far as the mechanical design of the arm, that’s where I’m kind of stuck, I guess. I’m assuming I’d have to get a motor shield for the arduino uno, and connect a motor to that. However, I have no idea how I’m supposed to connect the motor to a mechanical arm. It doesn’t need to descend more than a 4 or so centimeters, with very little force.

Thanks for the reply, and sorry for such a vague description.

Can you mount a servo nearby, and just rotate the arm around to push the button.

I got this funny smile on my face, thinking of the intro to Back to the Future ...

If you don't mind ugly-looking thing, just a rod on the servo and another one at 90 degree cal press a key. Is the key a key on a key board or something that requires much more force to depress? That will decide if a weak servo is enough.

  ----------------------- (to motor shaft, motor rotates clockwise to depress the tip)
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Key here

You can also use a servo to lift a small weight over a fixed pulley. Lower the weight to press the button. How's that sound?

CrossRoads: Can you mount a servo nearby, and just rotate the arm around to push the button.

I got this funny smile on my face, thinking of the intro to Back to the Future ...

I see, the cat feeder?

dog food, but not so much that as the whole mechanism leading up to it starting with the alarm clock ...

CrossRoads:
dog food, but not so much that as the whole mechanism leading up to it starting with the alarm clock …

Right, right. My memory of the movie was a bit fuzzy but now I remembered the dog’s name was either Einstein or Newton. I didn’t google it :slight_smile:

Einstein sounds right, haven't seen the movie in a while.

Thanks for all the replies guys. I think I'm going to try for something like this: http://www.instructables.com/id/Controlling-Hand-Drill-with-Roboduino-Arduino-to/step3/Servo-Thottle-Control-on-the-Drill/ for the pressing of the button. The button is kind of like a key on a keyboard, just bigger and rounder. Kind of like the buttons you get on arcade games.

So in order to use a motor like that, I'd need the motor shield on top of the arduino uno, right? Could I put an LCD display shield with buttons on it on top of the motor shield to display to choose the time input? And how hard would it be to make the time input accurate to 0.01 seconds? It really needs to be exact, the button needs to be held down for exactly the amount of time that is inputted from the LCD.

Thanks.

lazyscranton92: Thanks for all the replies guys. I think I'm going to try for something like this: http://www.instructables.com/id/Controlling-Hand-Drill-with-Roboduino-Arduino-to/step3/Servo-Thottle-Control-on-the-Drill/ for the pressing of the button. The button is kind of like a key on a keyboard, just bigger and rounder. Kind of like the buttons you get on arcade games.

So in order to use a motor like that, I'd need the motor shield on top of the arduino uno, right? Could I put an LCD display shield with buttons on it on top of the motor shield to display to choose the time input? And how hard would it be to make the time input accurate to 0.01 seconds? It really needs to be exact, the button needs to be held down for exactly the amount of time that is inputted from the LCD.

Thanks.

0.01 second is quite short. A mechanical button bounces around when you press it for that amount of time before settling down into depressed. What is the reason for such accuracy?

For LCD, if your servo shield is stack-able, yes, stack an LCD shield above it. But be sure the two shields don't conflict in their pins. Which exact shields have you looked at? Care for a couple links?

liudr:

lazyscranton92: Thanks for all the replies guys. I think I'm going to try for something like this: http://www.instructables.com/id/Controlling-Hand-Drill-with-Roboduino-Arduino-to/step3/Servo-Thottle-Control-on-the-Drill/ for the pressing of the button. The button is kind of like a key on a keyboard, just bigger and rounder. Kind of like the buttons you get on arcade games.

So in order to use a motor like that, I'd need the motor shield on top of the arduino uno, right? Could I put an LCD display shield with buttons on it on top of the motor shield to display to choose the time input? And how hard would it be to make the time input accurate to 0.01 seconds? It really needs to be exact, the button needs to be held down for exactly the amount of time that is inputted from the LCD.

Thanks.

0.01 second is quite short. A mechanical button bounces around when you press it for that amount of time before settling down into depressed. What is the reason for such accuracy?

For LCD, if your servo shield is stack-able, yes, stack an LCD shield above it. But be sure the two shields don't conflict in their pins. Which exact shields have you looked at? Care for a couple links?

I mean, it doesn't necessarily have to be that accurate, but it needs to be pretty accurate. The button that's being pushed controls another machine that raises a platform up to a certain height, and this takes a certain amount of time. There are separate levels, so I need to be able to input different time intervals so the button can be released at the right height.

I haven't looked at any shields yet, I actually didn't know anything about arduino until this morning. How can I make sure the shields are stackable? And how will I know if the servo fits in the motor shield?