To get enough outputs from the PIC chip, a pair of 74HC164 shift registers was used. These need only two lines from the PIC (data & shift) to produce the twelve signal pulses for the servos. A single bit is shifted into the first shift register, then, after a specific delay, it is shifted to the next servo. The second shift register cascades off the first. This system can be extended for any number of servos. The idea of this design is that no power is needed when the legs are in the full down position. They also create a lot of extra leverage at the bottom of travel. This helps overcome friction as the leg is moving horizontally inward at this time. When the leg is raised, the velocity increases with height making it easy to raise the leg over an inch.
Click here to download the full size of the above Circuit.
The platform on top holds the downloader board when trying out new code. The full schematic is available for download as is the source listing. As of this point, I have worked out walking forward and backward, and turning left and right. The rest, as they say, is left as an exercise for the student.
The HEXBOT is constructed from 12 (cheap) model airplane servos. Each leg moves laterally on one servo and vertically on the other. Conveniently, this type of servo runs on 5 volts. These servos need only a specific width pulse to position it. Once it arrives at its target location, it draws very little power (about 10 ma). Power is provided by a set of four AA metal hydride batteries mounted underneath. Neither the servos or the PIC requires highly regulated power.
An earlier version of the hexbot had legs made out of 1/4 inch aluminum square stock with a 90 degree bend. This caused the vertical servos to draw a lot of power just standing still. It could barely walk. The new leg design uses a piece of 1/2 inch aluminum angle stock (see the close-up), and two peices of the 1/4 inch square stock. The parts are joined with #6 screws and those plastic-insert 'aircraft' nuts. The nuts are tightened just enough to take up the slop but still allow movement.
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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