Robotics

The capacitor charges until the PNP transistor (here shown as a 2N3906, but you could also use a BC327) receives base current through the Zener and turns on. Then the NPN transistor (here shown as a 2N3904, but you could also use a BC337) turns on and the capacitor is discharged through the motor. As the NPN turns on the 2.2K resistor starts to supply base current to the PNP and the circuit snaps on...

You can drop all off the transistors and resistors if your motors don`t drain too much current. You only need a 74F139 or 74S139 NOT the LS version. The chip can provide peak currents up to 100mA for a short time (<1 second) and to one output at a time. This is for normal connections. I don`t know how far you can go with this misbehavior. It`s nothing special, but you get the idea how it is done...

One of the nicest features of the 8-bit KX8 microcontroller (manufactured by Freescale Semiconductor) is that it includes an internal clock generator (ICG). This allows the chip to run without the trouble and expense of an external crystal or canned oscillator...

Bugdozer is an autonomous mini-Sumo robot. Her main board consists of a MC68HC908GP32 microcontroller along with input/output support chips, a voltage regulator, a crystal oscillator, and the usual assortment of resistors, capacitors, and switches. All chips are socket mounted. I`m not experienced at soldering, so soldering the sockets avoided damage that could have resulted from soldering the chips directly. Also, if a chip becomes damaged in battle, it can be replaced easily...

An 8-pin Atmel ATtiny45 microcontroller uses one of its analog-to-digital pins to measure the voltage divided between a 4700 ohm fixed resistor in series with a BC Components 2322 640 66103 NTC 10 kilohm thermistor (Digi-Key BC1482 $0.68). The thermistor changes resistance in a predictable way based on the temperature...

The microcontroller is able to make about 7000 complete line-following decisions per second, which is almost 7 decisions per millimeter when the robot is going full speed. By upping the clock, unrolling loops, and removing my wireless debugging and extraneous code, I could increase the number of decisions per second...

RF is just way too cool not to use in your designs. But if you`re a newbie like me it is difficult to successfully build solid RF transmitters and receivers. When I started out I didn`t realize that the larger breadboard I was working off of was causing a lot of the signal deviance because the metal traces on the breadboard worked like small capacitors and changed my circuit dynamics. So after much research I found the Reynolds Electronics RWS and TWS 434 RX/TX pair...

One of my student has made a disgraceful robot that used two stepper motors and with a simple IR sensor. Yes, above picture is what I`m talking. Without battery carrying, a little bit torque of the stepper and misalignment of driving shaft, makes it crawling not walking, but first demo, showed quite impressive to me. He said he wrote a couple of program lines using C, his robot can track the black tape. I feel delighted his intention and endeavor. I thought, " he borrowed me DS5000, expensive one, a soft uController with internal bootloader, why shouldn`t try with our learning board C-52 Evaluation Board instead"...

The two photoresistors are used as eyeballs, the left one is used to turn left,the right is to turn right. The "feather sensor" has finally been worked out and will be used for turning the robot with out getting stuck on a corner. In other words when AI-A-1 turns left and is about to hit something the "feather sensor" touches the object and activats the reverse function. The robot has a circut with a capacitor and a power MOSFET that controlls how long to go in reverse. this circuit is coneceted to the "feather sensor" switch...

The digital navigation PC board may be configured for a number of navigation functions, see figure 1. It may be made into a simple visual digital compass, or a microcontroller based compass. The microcontroller based compass can be used for mobile robotics or a PC based compass...

A strap-down inertial-navigation system uses silicon sensors to measure displacement without entailing the bulk and expense of moving parts or GPS receivers. For example, a three-axis accelerometer and three angular-rate sensors can determine the position and velocity of a vehicle such as a robot or radio-controlled aircraft...

By using two 8-bit ADC channels for the same signal, the technique in Figure 1 can accommodate both conditions. One channel, which the controller uses for fast motion, reads the input directly and adds four 0 LSBs for a 12-bit result. The second channel reads the signal amplified by 16 with four 0 MSBs. The amplification gives this channel the resolution necessary for small-error signals while the robot is traveling a nearly straight line...

The circuit here are designed to be integrate to strboscope circuits so that they can triggered using external trigger pulse. The standard trigger pulse used in professional stroboscope controllers is 3-10V pulse. If you don`t already have a suitable controller, you can built one based on my stroboscope controller design. Stroboscope circuit use lethal voltages, so you must be very careful when operating with them. When the stroboscopes are triggered using an external signal, then there are some extra safety things to consider. The safest way is to provide a complete galvanic isolation of few kV between the trigger input and the stroboscope circuitry. This isolation can be done using and optoisolator or transformer isolation. CAUTION - high voltage of strobes can cause a nasty and possibly fatal shock. The energy storage capacitor can retain dangerous high voltage after power is removed from the board...