Some things seem like, for all time, they will evoke a response. The humble music box, the plinking of tines on a rotating drum… falls right into that category for me. This Happy Birthday Song Mechanical Music Box has been brought wonderfully into the modern age by means of a DC motor and a small PCB.
It’s quite elegant! Looking at the pictures on the product page, the rotating drum with the tine actuating pins on it has a gear on the edge. There is then another gear meshed and a shaft running out with another spur gear on the end which sits on a worm gear on the DC motors output. The motor is hooked up to two pins, EN and GND. If you apply a PWM signal between 3 and 5V to the EN pin you will enable the drum to turn and the music to play. Of course, varying the PWM means that you can vary the tempo of the playback.
Over on the product page, you can find an example where they have hooked up the device to an Arduino and patched in a rotary encoder and a button. They can then use the button to start and stop playback and the encoder to vary the tempo. While the Arduino demo is great, we can imagine it being pretty straightforward to hook this up to any microprocessor. Adding sensor-based control for example could lead to some fun projects.
If nothing else, it’s a wonderful electro-mechanical way to say happy birthday to someone and could be incorporated into a wonderful gift!
In most robotics projects, there’s an age-old conundrum. Do you pick the motors or the motor controller first? Sometimes the project requirements make the decision for you, but in lieu of that, you’re left with a “chicken or the egg first” type of problem.
That is, unless, you’ve found the perfect DC motor controller with a huge range of motors that will work with it with no problem! Enter, the Dual motor controller from Island Robotics. At a price point that would make any robotics enthusiast drool, and flexibility in spades, it is perfect for your next project or just to keep on hand for any spur-of-the-moment build.
This dual motor controller gives you flexibility in input power between screw terminals or XT30 connectors, and a buffet of motor connector options like JST, screw terminals, or even 6 pin motor connections to allow for encoder feedback. The board is able to handle 5-18V and up to 4.5A for each motor, and with a built-in closed loop speed control feature, it’s the perfect companion for just about any brushed DC motors out there. And as the cherry on top, the board is controlled over I2C, and already has a microPython library written by the creators themselves, so integrating it with your favorite microcontroller or microprocessor is a breeze!
If you’re looking for more lovingly crafted robotics components, be sure to keep an eye on the Island Robotics storefront. They’ve already got other wonderful add-ons like these ultrasonic sensor PCB mounts which would make object avoidance in your next robot build that much easier.
Designed and sold by SGROBOTICS in Singapore, this infra red motor control kit is friendly for those who are new to soldering and perfect for projects requiring two motors!
Infra-red is a fun and affordable control system to play with, certainly capable of making reliable wireless systems for indoor use. The kit comprises of through-hole components only, which means that they’re larger, easier to handle and can be held in place more easily when soldering. These factors make this a great kit for first time solderers.
Motors aren’t supplied with the kit but you should have no trouble finding some that are suitable to run at the 6V provided by the 4AA battery holder. The two motors are attached using wire terminal blocks for ease of construction and, once set up, you have forward control of each motor with three levels of speed. Simple two motored vehicles can use the ‘skid steering’ approach where you simply stop one motor and rotate the other to create a turn to the left or right. For small robots you wouldn’t miss having reverse as they can virtually turn on the spot.
Provided with a construction guide, this is an excellent kit for beginners and you could easily have your latest robot creation up and running in a hour or so.
Motors01CJC by C_J_Cowie via Wikimedia Commons CCA-SA 3.0
If you like to make things—and you’re reading Tindie’s blog so that seems like a fair assumption—at some point you’ll want to make one of your creations move, likely with a motor of some sort. We can help you decide which kind of motor best fits your application. Read on!
DC Motors
DC motors are the simplest rotary motion devices on this list, as movement is started when sufficient voltage is applied between the positive and negative poles. Speed can be controlled by varying this applied voltage, and direction is changed by reversing input polarity. By default, there is no feedback to tell you how fast this type of motor is going. If needed, an encoder can be added to sense speed, and gear reduction can be used to increase output torque at the expense of rotational speed.
While easy to control, they need more current than an Arduino or similar dev board can generally provide. For an easy way to integrate a motor with this type of control, just do a search for Arduino “motor shield” for lots of options, many of which will also work with the other motor types discussed here.
Stepper Motors
Sometimes confused with servo motors, stepper motors operate by energizing certain coils to make a shaft turn one step at a time. This requires more thoughtful control than a simple DC motor, but also gives it the ability to move in a precisely controlled fashion. While there are many uses for this type of device, one notable use is in CNC equipment. For a great illustration of how one of these work, check out the video above of YouTuber Proto G’s 3D-Printed Stepper Motor.
For CNC control options, if you’re interested in driving one in a laser or plotter project, this board looks interesting. It’s meant for use with the Grbl software package, which has become the de facto CNC control standard for Arduino boards. Alternatively, this shield gives a more general Arduino/Grbl implementation, including a connection point for your Z-axis.
Servomotor
Servomotors, or just servos, come in all shapes and sizes, but feature a feedback loop. This means that if there is an error in the motor’s position, the controller knows about it and can take the proper corrective action. Steppers, while generally extremely accurate, don’t have this ability, and if your system somehow misses a step, all further actions from there on out will be inaccurate until it’s re-homed. For many Tindarians, “servo” is synonymous with the hobby servos that are seen in model airplanes and the like. While these work well in many applications, other models are available that can cost thousands of dollars, many of which can rotate continuously with feedback.
Incidentally, you’ve likely heard that you can modify a servo for continuous rotation. After doing this myself, calling these modified motors “servos” is a bit of a misnomer, as there’s no longer any positional feedback. They are simply DC motors in a convenient format with a modicum of speed control. That being said, if you do need positional feedback, then you can add a Mocoder encoder to one of these modded devices, restoring a sense of control to your system!
Of course there are other electro-mechanical options, such as AC motors, solenoids, and variations of the motors listed here. Hopefully this gives you a good place to start if you’re considering building a new robot or other moving device!
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