Solenoid engines are nothing new, though they still seem to be a fairly common project among the curious. Using a hard drive makes such a project much more simple and straight forward, that is if you want to keep it that way.
This solenoid engine uses a software control loop (code below) running on a 16MHz Adafruit Trinket to adjust its speed. The program specifically alternates between a modest 180RPM to a smashing 3000RPM every five or ten seconds! Watch the video below!
My (not so) fancy-like PC has recently developed this issue where it, regardless what the power settings are set to, will always go to sleep within one or two minutes of inactivity. I found this to be an incredibly large nuisance when it came to watching videos, 3D printing something over USB , or just brainstorming in front of the keyboard basking in the warm glow of the monitor; the PC will never fail to go to sleep after a mere matter of seconds.
After much wasted time in the many Power Options windows, and after hunting through old, seemingly irrelevant forums, I have decided to bring yet another Adafruit Trinket to the rescue.
In less than a dozen lines of code, I got the Trinket to “poke” the mouse once every 59 seconds. The net movement is 0 pixels over time, and the “poke” occurs in a matter of a few clock cycles.
Check out the code below:
It’s alive! The tricopter went under a few more revisions and prints before finally taking to the air. My old Rev One Quadcopter has been reduced to it’s (over-engineered) frame and nothing more. Its parts (motors, ESCs, batteries, Crius AIO, etc.) have moved on to become this very tricopter.
Currently (in the picture) it is set up to fly FPV sans-GoPro. There is an optional part available to replace the camera pan/tilt servo mount/hole with an alternative “use-what-you-want” vibration-dampened plate.
Keep reading for a couple closeups and highlights of the tricopter.
The frame is now prototyped and measurements are almost final. Several small changes were made to the source files as result of this prototype (now on internal-revision #24). These changes included primarily wider tolerances and smaller hardware requirements. Other potential ideas are still pending (in particular; optional “taller” landing struts, ESC/wire management, and AIO mounting).
Changes to the last update included primarily, universal motormounts. Now it’s not necessary to use a specific cross plate on a limited range of motors. I’ve adopted the standard 16/19mm hole spacing used on many motors appropriate for this size multicopter. Also, the mount’s face is now flat on both sides, so you can more easily mod them (drill holes) for a specific motor that doesn’t follow these standards. With this, you will need to use 8mm M3 socket cap screws (instead of the shorter, countersunk M3 screws often provided with your motors) to mount said motors to the mounts.
The frame still needs to be prototyped on my printer, though I have modeled the finished project to get an idea of the size.
The distance between motor-centers is roughly 625mm when the two front 1/2″(12.7mm) wood dowels are cut to 350mm and the tail to 310mm (-40mm). This was necessary to accommodate the inline motor hinge that pivots on the axis of the tail arm. These dimensions, along with other things, are subject to change after the prototype gets printed.