Soil Moisture Control System|
For a recent design contest sponsored by Microchip and Circuit Cellar I designed and built an automatic soil moisture control system. It controls up to 5 houseplants, measures the moisture with stainless probes, and turns on pumps or valves to water the soil when needed. It can either be programmed via rs232 cable or it can learn from one's existing watering habits.
It is controlled by a Microchip PIC microcontroller, runs at 10MIPS,
has fully buffered rs232 IO with two bullet proof 256 byte FIFOs with
full flow control support.
XYZ Plotter Project |
Added third (Z) Axis to standard flatbed plotter.
Over 5000 DPI resolution is attained with a 200 step per revolution tape drive stepper, and a floppydrive head seek screw.
The controler has two switching voltage converters inside, and all the support circuitry to run the 80 character backlit alphanumeric LCD, the custom touch screen, beeper, thumb jog wheel, and 16 key keypad. Controled over the printer port, the software runs on a PC. Allows full 3 axis control of the plotter. More pictures and text.
XY Video Microscope|
X-Y Stepper controled pan for microscope specimen, and stepper motor control for focus, all using rack and pinion head seek assemblies from old hard drives. Not shown, a lense is clamped in, and focuses the image onto face of video camera image tube. Also not shown is stepper motor driven zoom axis, using print-head carriage system from old wide impact printer.
See pictures taken with this:
2.5/1000 inch glass optical fiber , with blue LED backlight. Or With incandescent backlight, more zoom
Racing mint tin|
PIC Microcontroler, 2.5MIPS, runs on single 3.6v Lithium Cell
Receives control commands at 1200 baud, RS232 timing over a low power 433Mhz radio link
Moves forward, and turns left to right in 128 steps.
Two motors, 2 Integrated Circuits, 5 transistors, and a charge pump to bring the 3.6 volts up to 5 volts for the receiver.
More pictures: Circuit Board , Assembled , With me and controling laptop
Using laser pen reflecting off cellophane in attempt to build very high frequency microphone.
Since we can get photo sensors that work into the Mhz, and since the actual area of the cellophane off of which the light bounces is very small, very high frequency response should be atainable. System worked well, but only to about 15Khz. Turns out the op amp I used was only good to 15Khz.
Radio Scanner project|
Converting an old handheld radio scanner into a two way radio. (And this is legal, because I'm a licensed Amature Radio Operator.)
So far, I've transmitted about 500 feet by just hanging a wire off of the first local oscilator.
IR light level sensor|
Used a single quad op amp (LM324) and a few transistors and passives to build a true 3-bit, 8 level, Analog to Digital converter, for measuring IR levels
Light following robot|
A simple robot that follows light. Very sensitive, and self adjsuting. Can follow sunlight to moonlight, without adjustment. Runs on cell phone battery.
IR Intrusion alarm 1:|
An IR Beam intrusion alarm, using IR LED, modulated at 40Khz or something, 2 inch glass lenses, with a range far in excess of 300 feet.
IR Intrusion alarm 2: Loudspeaker|
Another IR intrusion alarm, but this one plays sound clips of explosions, wild animals screaming, etc. when the IR beam is interrupted.
There are 10 six-second long audio clips stored in a solid state sound recording chip. Each time the IR beam is interrupted, the next sound clip in the list gets played.
Qbasic logic/integrator simulator|
A QBasic program that simulated logic, and an integrator. More info