In this class we will discuss various techniques of mounting servos, steppers, and DC motors. As well as cover objects that can be mounted to said motors.
“Motoring what’s your price for flight”
— Night Ranger
Show and Tell
We’ll review and discuss last week’s assignment. What processes/techniques/tools did we use? Any tips? What would we change if we could do it all over again?
Tool of the Week
The metal hole punch is great for making very clean holes in sheet metal.
Tip of the Week
“Off the shelf is almost always better than custom parts”
Off the shelf parts are almost always cheaper, easier to work with, and just a better idea than custom made parts.
We are familiar with operating/controlling servos, DC motors, and steppers; but we may not be too experienced with using them practically or consistently in projects. There are numerous ways to mount motors as well as ways to attach things to motors. Below are a few off the shelf and DIY solutions.
Servos typically have mounting holes, but I find them to be awkward when using them to screw directly into an enclosure or mount. Store bought mounting options, although pricey, are worth the price for convenience and repeatability.
DC motors are cheap and easy to operate, but are tricky to mount into projects. Typically, you will use a “toy” or “mini” DC motor in your projects. Below are a few off the shelf options for various sized motors.
TIP: When pulling DC motors from the junk shelf, KEEP THE SCREWS that came with them. In fact, just leave them screwed into the motor.
Steppers typically have mounting holes in the front near the spindle. Mounts are pretty straightforward but should be fairly robust to ensure accuracy in your mechanisms.
Mounting Things to Motors
Not only do you need to know how to mount motors, but also how to mount things to motors. Below are a few off the shelf solutions.
These typically come with servos and if you need something fancy they can be found in many places on the internet, the trick is knowing that they are called “horns”.
Timing Belt Pulleys
Timing belts and timing pulleys are typically used with stepper motors for precision devices (CNC’s, mechanisms, etc.). The pulleys can mount directly onto the shaft of a stepper and the teeth of the pulley fit the teeth on the belt. The trick is to match the tooth pattern of the belt to the tooth pattern of the pulley (like to like).
Screw terminal blocks are a cheap electrical component that can be found at most hardware stores. It is filled with little metal couplers that work great for connecting motor shafts to axles and rods. The trick is getting the metal parts removed from the plastic.
Self Adhesive Cable Tie Mounts and Zip Ties
Laser Cut Panels and Standoff DC Motor Mounts
Sandwiching DC motors between to laser cut panels using standoffs is a quick and reliable method.
Laser Cut Stepper Mounts
Using the laser cutter and acrylic bender you can make quick and dirty stepper motor mounts. I do not recommend these mounts for precision devices.
Laser Cut Adjustable Tension Stepper Mounts
Using two laser cut parts (one stepper mount, one base) and some fasteners, you can create a mount that allows you to add tension by changing the position of the stepper. Perfect for timing belts.
Full Motor Assemblies
You can even buy full motor/gear box/axle/wheel assemblies.
Mounted Motor Projects
In Class Demo
We will go over the sander, grinder, and bend.
For the last assignment you will be mounting a motor/servo/stepper (one or more) to something as well as mounting something to that motor/servo/stepper. It can be completely DIY, or off-the-shelf components, or a combination of the two.
Everyone will present their project in class.
Post your progress and project to your blog.
Di-Dah-Dit (enclosure, mounted servos, mechanisms, laser cut parts, the works)