The 2009 Robot Rally spotlighted all the flaws that result from a quick 3 week engineering and building project. Time saving shortcuts in code and hardware bit my butt several times. Failed edge detectors - Ouch! Failed beacon tracker. chomp! Ow! Line follower reversal - Arrrg! I`m happy to report I`ve investigated all the issues that cropped up
Click here to download the full size of the above Circuit.
and fixed them all. The bot still isn`t perfect but it`s a whole lot better than before. I`ve also cleaned up the software code and documented it better. Here`s what has been changed and fixed. Source code and schematics may be downloaded from links at the bottom of this page. The Atmel AVR ATMEGA8535P was full. I used all 8192 bytes of program space. There was no room left for enhancements or bug fixes. So, I ordered some ATMEGA644P chips from DigiKey. Only Five bucks each, such a deal! These are hardware pin compatible with the old 8535 so no hardware changes were needed. They have 64K program memory and 4k RAM. This is 8 times the memory of the old CPU. They are mostly software compatible too. Yeah, "mostly". That means spending a lot of time going over the code and finding the differences in the names and bit functions of all the internal configuration registers. Also, the avr-gcc open source compiler and avrdude program downloader I had didn`t support the 644 so I had to hunt down the latest version for the Mac. I downloaded and installed AVR Crosspack. Several days were spent hunting down bugs caused by the CPU upgrade. L293D h-bridge chips suck. They have nearly 2 volts of drop across them and run hot as hell. I was using two in parallel for each motor and they still ran very hot. Due the voltage drop the motors only got 10 volts out of 12 that was available. This means that top speed is reduced by about 20%. So, I...
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.....
characters left: