Here is a great project for learning how to control servos. They’ve made a USB controlled squirt gun using the USB NerdKit, a pump and a servo. This is a great tutorial to learn about PWM and controlling servos. The tutorial is very thorough, with great pictures and a video of it all , which you can see after the break.
oomlout has posted some interesting plans for a simple robot. It’s based around an Arduino and is a platform similar to the Parallax Boe-Bot. The Arduino sends PWM signals to continuos rotation servos that drive the two main wheels. All of the structural components are laser cut from acrylic with slots to hold standard hex nuts. It’s an interesting technique, but the design has a lot of potential for improvement. Right now it uses two different power supplies and a breadboard for simple connections. From the video below, you can see that the balance could be improved as well. Continue reading “Simple Servo Bot Plans”
We mentioned Pulse Width Modulation (PWM) when talking about [sprite_tm]’s marquee control. It’s a method of power control. While [sprite_tm] did it in software, [Afroman] sent along a very straight forward introduction to PWM using just a 555. Check out his video for coverage of this fundamental electrical design technique.
In a previous job, [sprite_tm] was responsible for wrangling many different LED text ad marquees. The hardware was fairly simple and he always figured they could be pushed much further with a little work. He recently acquired ten 32×16 LED displays a decided to see what he could do with them. By the end of the project, he had full motion video running on the display. This is a great project to read up on if you’ve ever wondered about LED matrix displays. He starts by reverse engineering the electronics on the board. He then attached an ATmega88 to drive the display module. Multiple display modules were daisy chained together over serial. The article covers PWM control and refresh timing as well. Check out one of a few demo videos below. Continue reading “Overhauling LED Marquees”
[John Peterson] created this postal scale device for a Renesas design contest. The Weasure not only calculates the package’s total weight but the dimensions as well. He built it using a SKP16C62P evaluation board that had an LCD, pushbuttons, and indicator LEDs. The original DigiWeigh parcel scale was modified to provide PWM output and tare control. He embedded photoresistors every inch along each axis. They were angle slightly upward and the surroundings were painted black to minimize reflection. The Weasure outputs everything via a serial connection so it can be used with shipping software to generate postage.
