Hello all,
     I just posted some pictures showing my lab and the frequency=20
counter that I am building. Keep in mind that this is just the=20
prototyping stage. I complete a section, build a test setup, and then go=20
on to the next section. The display board that is mounted to the larger=20
board is completed. The larger board is just a test fixture that I will=20
disassemble once I am finished with it.
     My PicKitII is just in front of the display board. Behind the=20
display board is one of my breadboards. It has the 74ls390s that are=20
driving the CD4511s that are on the display board. You can also see the=20
PIC16f684 on the right side of the breadboard. It is operating as a=20
timebase and it controls the reset and gating functions. Eventually I=20
will hook up a switch to control a variable timebase and the positioning=20
of the decimal points. There will also be a pot to control the length of=20
the display. Right now the display time is fixed at 5 seconds. On the=20
left side of the breadboard is the signal conditioning circuitry and the=20
NAND gate that is being driven by the gating signal coming from the PIC.
     Behind the breadboard is my home made power supply. The meter on=20
the far left is a 0-5 ammeter. The power switch, fuse, and the power=20
light are next and in that order from bottom to top. The next meter is a=20
0-15 voltmeter. Next is the control for the variable voltage regulator.=20
This is just the good old LM317. It is heat sinked to the back of the=20
case. The fuse blown indicator is the red lamp that is above the pot for=20
controlling the variable regulator.
     The five green LEDs are +5, -5, +12, -12, and variable voltage=20
indicators. These are hooked up right at the output pins of the=20
regulators except for the adjustable regulator. It is hooked to the=20
input pin. The rotary switch below the LEDs control which voltage and=20
amperage are being displayed on the meters. This switch controls a=20
series of small relays that switch the proper voltage regulator to the=20
proper meters.
     Behind that is my Tek 465B O-scope. To the left of the scope is my=20
HP 5245L counter. The counter is showing the same 32.768KHz signal=20
coming from a maxim DS32khz chip. This same signal is being displayed on=20
my frequency counter and on the scope. My meter is reading +-1Hz of the=20
HP counter. As you can see on the scope the signal has a very nice rise=20
and fall time. The HP meter is connected to the back of the scope. This=20
is the output of my front end circuitry for my counter. The front end=20
will accept a signal as low as a few millivolts and to as high as 25=20
volts. Sine, square, or irregular.
     Everything is running on a regulated 5 volts and it is drawing a=20
little over a 1/4 amp. There are pictures of the scope and HP counter=20
and the home made counter and power supply. I would like to hear others=20
comments. I hope that you enjoy. I'm happy. :)
     Who posted the pictures of the racks of Tek equipment? I would like=20
to know if that is possible.
Thanks,
rich!

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