LiTeRo, short for Little Telepresence Robot, is a DIY Raspberry Pi powered robot that can be controlled from any web browser from anywhere in the world. We wrote a single Python program in conjunction with a lightweight AJAX-style communication standard to achieve extremely low latencies with relatively few software dependencies.
LiTeRo is as a do-it-yourself project is designed to be exceptionally modular and customizable. By default, it was designed to sport a wide angle Raspberry Pi camera, High-power IR navigation LED, 9-DOF IMU, 4Ah LiPo battery (with monitoring), and a roll-in charging dock. Also incorporated later in development was a method for verbal communication. That’s right, LiTeRo can speak nearly 50 languages with the eSpeak Text-To-Speech (TTS) engine! Other TTS software packages for the Raspberry Pi can also be implemented with relatively minor revisions to the Python program. The robot can also sport a number of 9g servos for basic environment manipulation or for self-righting maneuvers.
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:
I pulled a couple 4Ah 3S LiPos from my tricopter’s stash and soldered together a little series adapter to give me an effective 4Ah 6S LiPo pack. The effective range has been cut in half to around 5miles compared to the original 13lb 10Ah SLA pack, but that’s still plenty enough to get someone around a college campus.
After years of waiting to find the right hardware, I have finally found the time and the opportunity to build my own digital mechanical clock that uses absolutely no transistors or ICs. Its technology is reminiscent of the early relay computers from many decades ago. It uses 67 relays arranged in such a way to create 21 identical flip-flop logic circuits.
It’s a simple idea. Just modify the source code from our Arduino IP Webcam project page and add an additional set of AJAX response lines that toggle a couple IO pins on the Arduino. You can have these pins go directly to some headers on your 3D printer and/or to an inline power-switch tail that you can toggle in the event of a problem. All the while monitoring your 3D printer visually with a live image feed from anywhere on the World Wide Web.
Heck, while you’re at it, you might as well add some remote controlled lighting, and a relay shield. Your only limit is your imagination RAM. Check out this simple user interface:
Over these past few months, I have slowly been testing out various materials for absorbing vibrations in the Revision III tricopter. The goal was to eliminate the rolling-shutter effect (or jello-effect) from aerial video as much as possible.
If you don’t already know, this tricopter has its battery and camera equipment suspended from the main frame with three zip-ties. Dampening materiel is loosely compressed or adheared between these two subassemblies and is ultimately responsible for most of the physical vibration isolation. Usually this materiel is rolled into three separate ~1″ long by ~5/8″ wide cylinders and stuck between each of the three zip-tie loops.
Among the materials I have tested include vinyl furniture bumpons, Sugru blocks, double sided foam (vinyl) adhesive, and latex foams among other things. Most worked pretty well, but others were hard to come by or showed poor performance.