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Switching regulator drives robot motor

Published:2012/11/9 20:24:00 Author:muriel | Keyword: Switching regulator, robot motor

Switching regulator drives robot motor
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clock generator

Published:2012/11/9 20:22:00 Author:muriel | Keyword: clock generator

clock generator
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IR slotted switch sensor

Published:2012/11/9 0:32:00 Author:muriel | Keyword: IR slotted switch, sensor

There is a type of detector known as a slotted switch that consists of a phototransistor/LED pair mounted on a solid frame with a small air gap between the two elements. A typical circuit might be: o +5v o +5v | | | | \ \ 220 ohms / / 4.7K \ \ / / | | | +-------> Vout _|_ / \ / |/ ----- |\ NPN | \ | | | | | | GND GND | air gap | When the air gap is unobstructed, the transistor saturates, pulling Vout to ground; when the gap is blocked, the transistor cuts off and Vout is +5 volts. (View)

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Minimizing SUN's noise in IR reception

Published:2012/11/9 0:31:00 Author:muriel | Keyword: Minimizing , SUNs noise , IR reception

A 'baffle' is a perforated disk or disks spaced inside your 'shade tube'. The idea is to trap all reflections, leaving only the light coming in on the exact axis of the tube to strike the IR Detector. __________________________________ | | | | DET <--- IR LIGHT | | | | ---------------------------------- ^Baff ^Baff ^Baff Off-axis light, 'noise', will be caught by the baffles and dissipated through reflection between the baffles. Paint the inside of your tube black ... in fact, check into what paints/coatings are 'black' to IR wavelenghts. Just because a paint LOOKS black does not mean it won't reflect IR. Check into an astronomy or optics group to get the formula for the ideal spacing of the baffles and how big a hole should be in them. Getting this right will improve your system performance. (View)

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A very STABLE 40khz generator

Published:2012/11/9 0:31:00 Author:muriel | Keyword: A very STABLE, 40khz, generator

A circuit that I have used before is based on the CD4060 (14stage binary counter) and a 640Khz ceramic resonator. The CD4060 is basically an oscillator and a ripple counter to divide the 640khz down to something more usable. Here is the pinout of the CD4060 (frequencies are assuming a 640khz input signal into pins 10/11/12 - circuit shown below): +-\/-+ 160hz 1 | | 16 Vcc 80hz 2 | | 15 625hz 40hz 3 | | 14 2.5khz 10khz 4 | | 13 125hz 20khz 5 | | 12 \ 5khz 6 | | 11 >---- see sub-circuit below 40khz 7 | | 10 / GND 8 | | 9 NC +----+ Sub-circuit for a 640khz ceramic resonator: 12 >----------------------+ 740pf | (you may be able to obtain 11 >-------+----+---|(----+ a resonator with builtin | | | capacitors and three leads) 640khz --- \ | res. O / 1Mohm | --- \ | | | | 10 >-------+----+---|(----+ 740pf | GND >----------------------+ A nice part about this circuit is that it delivers a STABLE 40khz signal, as well as delivering several other frequencies that can be used to modulate the 40khz carrier. For example, the person that designed this circuit (Ken Boone, member of Triangle Amateur Robotics) used it to build several beacons in his yard to serve as navigation points for a robotic lawnmower. By diode-OR'ing the results of the 40khz carrier and one of the lower frequencies (such as the 125Hz) line to drive a ring of IR-LEDs, he could locate the beacon and tell which, of several, beacons he had found. This circuit has proven to be VERY stable, and is fairly inexpensive (about $1.50 for the CD4060 and 640Khz ceramic resonator). (View)

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Cheap 40KHz clock

Published:2012/11/9 0:30:00 Author:muriel | Keyword: Cheap , 40KHz , clock

Use a 40KHz Xtal and a 74C14 schmitt trigger: ________ <---------------- 2.2 M resistor ___| 2M2 |___ | |________| | | | | | | |\ | | | \ | +-----| O------+--------> Output 40KHz | | / | |/ gate 1 of 74C14 | | --+-- XXX 40KHz Xtal --+-- | | ----- --- - This circuit has worked for me in many applications. (it might be an idea to buffer the signal befor using it. (There are still 5 unused gates in the 'C14.. :-) (View)

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IR EMITTER CIRCUIT

Published:2012/11/9 0:30:00 Author:muriel | Keyword: IR EMITTER CIRCUIT

+5V 555 +5V | TIMER | / +-----------+ | \ 1| |8 | / 10ohms GND -----|GND Vcc|-----+ \ | | \ / | | / | 3| | \ 2.2K +-------------------|OUT | / | | |7 \ | | DISCH|-----+ | 4|- | \IR LED ||--+ +5V -----|R | / <|| | | \ 200K ||--+ | | / | 2| |6 \ | +---|TRIG THRES|-----+------+ | | | | | | | | +-----------+ | | GND | | ----- .1uF | | ----- +---------------------+ | | GNDNotes: Adding more IR LED's will increase the range of the IR detector. The signal on pin 3 of the 555 is 30Hz and has a duty cycle of 50% Due to the very small pull-up resistor the 555 sinks about 109mA. The specs say the 555 can sink up to 225mA so it's well below the danger level. (View)

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Infra Red Remote Transponder

Published:2012/11/9 0:30:00 Author:muriel | Keyword: Infra, Red, Remote Transponder

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Building an Intel 8008 Computer "Clock"

Published:2012/11/9 0:29:00 Author:muriel | Keyword: Intel 8008 Computer, "Clock"

Building an Intel 8008 Computer Clock
Be aware that I cheated this time around, at least I feel that way. In this design I use many modernly available shortcuts such as programmable logic devices and a high density ram. These devices were not available back in the 70’s. In doing so I do not believe I compromised my goal. My goal was to build a clock, not become crippled and blind, wire-wrapping two hundred IC’s. Unlike my teenage years, I don’t have unlimited time, and I now have a mortgage… I no longer mow lawns for a living, as I did at fourteen. Please understand this is a fully operational 8008 computer. Its 16k of memory space can be configured to use several combinations or RAM and EPROM. I designed in four input and four output ports. It also has a fully functional front panel that can be used to examine or modify memory, or jam in an interrupt instruction. If you are a purest, feel free to convert the PLD algorithms to random logic to build a more authentic computer, though doing so may require modifications to compensate for timing delays. Also remember you cannot load the 8008 down with more than one TTL load. You must buffer all signal lines coming from the CPU. You should also keep in mind that adding more logic chips will increase the power requirements. (View)

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17 LEDs in four groups bar-mode sequence Suitable for shop-windows animation etc.

Published:2012/11/9 0:27:00 Author:muriel | Keyword: 17 LEDs, four groups , bar-mode sequence

17 LEDs in four groups bar-mode sequence Suitable for shop-windows animation etc.
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Binary Coded Decimal (BCD) Clocks

Published:2012/11/9 0:26:00 Author:muriel | Keyword: Binary Coded Decimal (BCD) , Clocks

Binary Coded Decimal (BCD) Clocks
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7-Segment LED Counter

Published:2012/11/9 0:22:00 Author:muriel | Keyword: 7-Segment, LED Counter

7-Segment LED Counter
This simple counter can be used to count pulses, as the basis for a customer counter (like you see at the doors of some stores), or for anything else that may be counted. The circuit accepts any TTL compatible logic signal, and can be expanded easily (see Notes). (View)

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PID Motor control

Published:2012/11/9 0:21:00 Author:muriel | Keyword: PID Motor control

PID Motor control
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30 Nanosecond Settling Time Measurement for a Precision Wideband Amplifier

Published:2012/11/9 0:21:00 Author:muriel | Keyword: 30 Nanosecond, Settling Time, Precision Wideband Amplifier

30 Nanosecond Settling Time Measurement for a Precision Wideband Amplifier
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24 Second Shot Clock

Published:2012/11/9 0:19:00 Author:muriel | Keyword: 24 Second , Shot Clock

24 Second Shot Clock
This is a circuit intended to be used in basketball shot clock.Notes:To start in 24 seconds; 24s LOAD SW and Reset SW should be push simultaneously. If not, the count will start in 99. Pulse input can be connected to 555 astable multivibrator but must be calibrated for real time clock. The PAUSE SW must have a Switch Debouncer so that the counter will count normal when counting is paused and then turn-on.When the count reach 00, the NOR gate will have an output of logic1 that will turn on the two transistor. The buzzer will rung and light will turn on. The two transistors are continuously turn-on not until LOAD SW and Reset SW is push. All have a +5v power supply. (View)