555 timer problem

I'm working on the "time fountain" project and have run into probably
the last of my problems. Here is the circuit (just strobing LEDs, and
a motor):

+6V
+------+ |
+6V>--+--[1N4001>]--+------|Vcc | [LED]
| |+ | | |K
| [1000µF] | OUT|----+
| | | |
GND>--|-------------+------|GND 5|--[.1uf]--|GND
| +------+
|
|
+--------------------------------------+
| |
| +----+----+
| | |
| [1N4001] [MOTOR]
| | |
| +------+ +----+----+
+6V>--+--[1N4001>]--+------|Vcc | |
|+ | | C
[1000µF] | OUT|---[R]--B
| | | E
GND>----------------+------|GND 5|--[.1uf]--|
+------+ GND

The top timer just controls strobing LEDs, and appears to be working
fine (though I have no real means to test it).

The bottom timer, however, gives me problems. I'm using a 1uf cap, 1K
for uptime, and 1K for downtime. (The configuration is such that one
resistor controls the cap charge, the other controls the discharge)

The motor is a tiny submersible 3vdc water pump. The problem is that
the frequency of the 555 timer will alternate. Ive hooked up a piezo
in parralel to the motor, so I can hear the frequency of the timer. (I
dont have an oscilloscope)

It will be high for a few seconds, then dip low for a few seconds, then
go back high. When this happens, it changes the RPMs of the motor
which changes the flow of water -- I need a constant flow of water. I
just need the motor to run steady at a certain rate, which it does, but
only for short bursts of time.

I need the 555 to stay as constant as possible... but for some reason
the 555 timer is giving me a hard time. Any suggestions? Thanks a
lot!

-sam


Another note: when I first turn on the rig it will work fine for a
minute or two, then it will start to give me problems. Don't know if
that helps.

.

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