Quick question - my first Arduino project :)

Hi!

I'm making a project and ready to order my very first Arduino.

It's an iphone app that can wirelessly wind or unwind a coil of string using a motor.

I've been doing my research and trying to figure out which parts I need to order. This is the area I'm uncertain about, and would really appreciate some feedback or recommendations to make sure I don't order the wrong things!

So far I figure I will need the following:
Arduino Uno
Bluetooth SMD Module
Servo Motor
L298N DC Motor Driver
Power Supply

Will I need to order anything else like wires or a breadboard? And is Bluetooth the best way for me to do something like this wirelessly or should I consider another option?

If you could help me with that, I would be really grateful, and even better would be some recommendation of specific parts to order if someone feels like going that far :slight_smile:

Thanks so much!

Other notes:
I'd like the wireless range to be up to 10 meters. The motor would pull something up to 2kg, and be fairly quiet. Ideally I'd like to keep it all under $100.

That's rather ambitious for a 1st project...

A servo motor is an angular motor and it doesn't rotate 360 degrees. No good for this application!

A stepper motor could work or a regular DC motor with some kind of revolution counter. Stepper motors are (relatively) slow and (relatively)noisy but that's probably the easiest way to go.

For either type of motor you'll need a motor driver. (Servos have the driver built-in but you can't use a servo.)

Will I need to order anything else like wires or a breadboard?

You always need wires but assuming you buy a pre-made motor driver you shouldn't need a breadboard or anything like that.

It's an iphone app that can wirelessly wind or unwind a coil of string using a motor.

I suppose you have a mechanical design in-mind, but I don't see how you could use the same set-up for winding and un-winding. (Except that you'll be automatically un-winding the supply spool when you wind.)

A lot of the Bluetooth SMD modules are not hacker friendly in that they don't have pins spaced at .1 inch for standard perf board or solderless breadboards. Also, they run on 3.3 volts, where the Arduino Uno runs at 5 volts, necessitating level shifting between all signals.
If this were my project, I would break it down into two parts, getting the UNO to wind the coil of string without the bluetooth, just a pushbutton or jumper interface. All you need is some pull-up resistors and jumper wires. Depending on what bus the Bluetooth or other device uses to communicate with the UNO, I would move to controlling it on that bus, after I have everything working the way I like with the wired interface.
For cost, the ESP32 is really hard to beat. It includes wi-fi and bluetooth (BLE as well) and is Arduino (IDE) Compatible. 79 US Cents each and includes an OLED display... Here's a "shield compatible" version.

DVDdoug:
A servo motor is an angular motor and it doesn't rotate 360 degrees. No good for this application!

A stepper motor could work or a regular DC motor with some kind of revolution counter. Stepper motors are (relatively) slow and (relatively)noisy but that's probably the easiest way to go.

Ahh perfect! I will use a stepper motor then. Thanks for that :slight_smile: good thing I asked :slight_smile:

DVDdoug:
I suppose you have a mechanical design in-mind, but I don't see how you could use the same set-up for winding and un-winding. (Except that you'll be automatically un-winding the supply spool when you wind.)

Hmm I was thinking of attaching a small coil of fishing line to the motor and rotating it clockwise or counter-clockwise to wind or unwind it.

Perehama:
If this were my project, I would break it down into two parts, getting the UNO to wind the coil of string without the bluetooth, just a pushbutton or jumper interface. All you need is some pull-up resistors and jumper wires.

That sounds like a smart approach. I'll start with that first then!

Perehama:
Depending on what bus the Bluetooth or other device uses to communicate with the UNO, I would move to controlling it on that bus, after I have everything working the way I like with the wired interface.
For cost, the ESP32 is really hard to beat. It includes wi-fi and bluetooth (BLE as well) and is Arduino (IDE) Compatible. 79 US Cents each and includes an OLED display... Here's a "shield compatible" version.

Great! Thanks for the recommendation :slight_smile:
Is it really 79c for basically the same thing that's on Amazon for $20???

Your reply was really helpful, cheers :smiley:

shutupandwhisper:
Is it really 79c for basically the same thing that's on Amazon for $20???

The part is 79 cents. Shipping is $60 USD. You might want to buy a few at a time....

Perehama:
The part is 79 cents. Shipping is $60 USD. You might want to buy a few at a time....

Ahh gotcha.

DVDdoug:
That's rather ambitious for a 1st project...

A servo motor is an angular motor and it doesn't rotate 360 degrees. No good for this application!

A stepper motor could work or a regular DC motor with some kind of revolution counter. Stepper motors are (relatively) slow and (relatively)noisy but that's probably the easiest way to go.

For either type of motor you'll need a motor driver. (Servos have the driver built-in but you can't use a servo.)
You always need wires but assuming you buy a pre-made motor driver you shouldn't need a breadboard or anything like that.
I suppose you have a mechanical design in-mind, but I don't see how you could use the same set-up for winding and un-winding. (Except that you'll be automatically un-winding the supply spool when you wind.)

If you want to wind the string like a winch on a crane, you really only care about the limits, not any point in the middle, although your app could stop in the middle at any time, it just wouldn't know exactly where it was at. This can be done with a regular DC motor and limit switches. A knot in the string at each end could be enough to trip a limit switch.