Rich Ottosen's PIC Projects

Schematics and code for some of these may be available directly from Rich. I don't have info on any of them, so don't send me email requesting them. Eventually some of them might be available here, but don't hold your breath.

If you want more information on any of Rich's projects you can give him a call at (303) 892-9352.

Really! I mean it! Don't send me email about these, as I don't know anything about them. Talk to Rich.

Printer tester

This was the first Stupid PIC Trick I did. The "Printer Tester" outputs strings of characters whenever it is plugged onto the computer end of an IBM style 25 pin printer cable. The power to run the PIC is obtained entirely from the INPUTS of the printer. To keep power cunsumption low, the PIC16C54 is operated at 450KHz using an LC oscillator.

Model airplane encoder

Model airplane decoder/servo interface

These two circuits are used as a pair. The encoder takes four potentiometers and three switches as inputs. The pot and switch positions are converted to a string of pulses like the one used to modulate a model airplane transmitter. The decoder takes this pulse string and separates out the 7 channels to drive standard model airplane servoes. A two wire cable is all that is required to send all 7 channels from the encoder to the decoder. Alternately, an infrared transmitter and reciever could be used in place of the wire.

Electronic shutter controller

Various switches and pots to control an external shutter for a large format camera. This is used in a dark room to allow an artist to highlight a subject with a light wand as the shutter opened and closed between setups.

Serial LCD terminal

A standard LCD module and four switches are used to create a compact RS-232 terminal. Several different display widths and heights are supported. Baud rate can be set using the front panel switches and saved in the data EEPROM of the PIC16C84. The first version was built to act as the display for the barometric altimeter.

Coffee Cup Finder

Many years ago an engineer I worked with often misplaced his coffee cup. The coffee cup finder is attached to the errant cup. If the coffee cup is left idle for a prolonged period of time, it beeps a few times to draw attention. A surface mount PIC16C54, mercury tilt switch and a PZT sounder are the major parts in this Stupid PIC Trick.

LCD digital clock

The LCD digital clock is a modified version of the Serial LCD printed circuit board. A power backup battery and power fail circuit were added. The time is set by RS-232.

Barometric Altimeter, serial output

Altitude is measured using an air pressure sensor. Current, minimum and maximum altitudes are transmitted as RS-232 a few times a second. The altitude can be displayed in meters or feet. The maximum altitude that can be displayed is about 15,000 feet. A PIC16C54, piezo resistive presure transducer and a pair of comparators make up the majority of the circuit. The A/D convertor is a ramp type. A ramp created by charging a capacitor is compared directly against the outputs of the sensor bridge; there are no amplifiers. This means that a single count is a just a few microvolts. The altimeter has been launched in a model rocket as well as used to get simple road profiles with a laptop computer in a car.

Electronic Tape Measure

This is truly an electronic tape measure. A precision 10-turn potentiometer and spring loaded cable are used in place of the graduated tape. The voltage on the pot is read using an Analog Devices AD7710 sigma-delta A/D convertor.

Oscilliscope Time Base Calibrator

An oscilloscope time base is controlled by a switch with about two dozen positions. The time steps are a sequence of multipliers of 1, 2 and 5 from seconds to nanoseconds. The PIC is used to generate a square wave that is one cycle per division for each position of the switch. The longer periods are created directly by precision timing loops in the PIC. The shorter periods are obtained from a counter clocked by a 100MHz oscillator. The PIC selects between its output or an output from the counter. Since this is a one-of-a-kind circuit, the PIC16C54 is pushed way past it's specified limits to make it run (marginally) at 40MHz. This saves some counter chips.

P.S. Even the 100MHz is not fast enough for proper callibration of fast scopes.

White Noise Generator

This is a white noise generator similar in output to a National Semiconductor Corp. MM5437. The noise is an output bit from a feedback shift register psuedo random number generator.

Mechanical Shutter Timer

Simple timer using a pot on an A/D input of a PIC16C71. A button press starts the timer which closes contacts of a reed relay for the duration set by the pot.

Weather Station

Measures temperature, wind speed and humidity. Temperature uses a National Semi. Corp. LM334. Humidity uses a Phillips humidity to capacitance transducer. Wind speed is measured with a small thermister as a hot wire anemometer. These are output by RS-232.

Video Test Pattern Generator

More or less standard bar, dot and crosshatch patterns as black and white interlaced composite video signals. A PIC running on a 14.31818MHz crystal oscillator does all the timing. A simple 4 bit D/A is used to get the gray bars.

Light Dimmer, serial contol

Phase controlled triac lamp dimmer using the PIC for the timing. The lamps brightness can be made to slowly change up and down over time.

Linear CCD Image Sensor Controller

Timing and control of a Toshiba TD143 single line CCD imager. This was made easier by using the optics and amplifier board assembly from a FAX machine. Presently the only way to see the output of the imager is with an oscilloscope.

If you want more information on any of Rich's projects you can give him a call at (303) 892-9352.

Really! I mean it! Don't send me email about these, as I don't know anything about them. Talk to Rich.

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Last updated August 21, 1995