Hello everyone, so not that long ago I started making this project that shows you where each of the planets in the solar system are (including Pluto). It uses a keypad and LCD screen to change the time and date, LEDs to light up the planets and sun, and uses DC motors to spin each of the planets. I will use about 8 wires for the keypad, 4 for the LCD (it is an I2C LCD), 9 for the LEDs, and about 2 for each motor with 9 motors(or maybe more if I can add any for spinning each planet on their own axis). So my question was because I am using all of these things that use a bunch of wires, what is the best I/O expander shield I can use for the Arduino Uno?
PSidle:
I will use about 8 wires for the keypad, 4 for the LCD (it is an I2C LCD), 9 for the LEDs, and about 18 for each motor (or maybe more if I can add any for spinning each planet on their own axis).
8 for a 4x4 keypad is correct
2 for an I2C LCD - the other two are power and ground, not data pins.
18 for each motor??? Are you thinking of 2 per motor, with 9 motors?
Really need to know what type of motor you will be using.
There also needs to be some way to detect the position of the planets, easiest is probably to set them all to a know starting position when the arduino powers up.
Hello David, I am sorry for the mistake but you are right, each motor will have 2 and there will be 9 motors. I was planning on setting a specified position for each planet to go to when the arduino is powered up, but I still have not figured it out yet. I am planning on using the Topoox 6 Pack DC 1.5-3V 15000RPM Mini Electric Motor (obviously will get more than 6).
PSidle:
David, wong I also need a bunch of new pins for power and ground and Power for the motors?
No, power and ground are all connected together AND power should not be supplied by the Arduino. Therefore, all you need to connect to the Arduino are wires for the common ground and a wire or two for the control signal(s) of the DC motor (you may need an H-Bridge for each motor).
You don't need nearly as many connections as you originally thought
Power_Broker, alright, thanks for clarifying that! What I meat by power is the 5V or 3.3V pins. And I was thinking that I might have had to use a H-bridge but I hoped I would not have to because it might take too much space inside of the box all of the components are going in but I guess I will have to. Is it physically possible to use more than one motor for one H-bridge connector (my guess is no, but if so, that would be great!).
I'm pretty sure most H-bridges are designed to control two DC motors at a time. This makes sense considering the vast majority of use-cases are for hobbyist self-driving rc cars (that need two DC motors)
Hello again, last question (I hope), should I use DC motors or Stepper motors for my project? Because then if it would be a stepper motor I was th inking of using 28BYJ-48 stepper motors (specifically the kit from Kuman).
H bridges are for motors that need to rotate in forward and reverse. Last I looked planets turn in one direction. Logic level MOSFETS and PWM could be used to control those DC motors. Much smaller, cheaper packages.
groundFungus:
H bridges are for motors that need to rotate in forward and reverse. Last I looked planets turn in one direction. Logic level MOSFETS and PWM could be used to control those DC motors. Much smaller, cheaper packages.
You are right, the planets do move in one direction, but when changing the current date to a date before, it would probably be easier to go backwards (and it will waste less energy) than to make one full rotation to the new position. But I will take a look at those MOSFETS and PWM logic levels. Again, will it be easier/better to use a stepper motor or DC motor?
DC motors are for spinning something at high speeds (generally) like the wheels of an RC car. Stepper motors, on the other hand, are slower, but allow higher positional accuracy.
