I see you love the "Rant". Missing a pulse per SECOND (not per week) causes the indifference to be significant. The pulses are so high and divided in order to create accuracy, along with the incredibly geared down box FROM the stepper motor. Again, my 3.5 meter is only accurate to 10 pps until I get a hold of a true frequency counter, and believe it or not, once I set a frequency on my meter (with the astable), it stays there (within TEN pulses, ex.- I set it at 773 in the /10 scale on my meter and it DOES stay there, but again, that's 7730 to 7739 which could result in several minutes of inaccuracy after a week). I didn't try a crystal because in time the gearbox/etc will develop more/less drag, and I didn't know how much drag I would have to begin with (my math was originally circa 6926.xxx pps before gearbox reduction and division by 100). In regards to regulating only the astable (which it DOES have a 7805), the device (seismograph, which is a seismometer with a helicorder) has a battery backup which would be simpler to integrate into the entire implementation with everything else during a power failure (the divide by chips, the 4-bit bi-di shift register, the drum limitation indicator flasher chips/leds/buzzer, the cooling fan, the battery voltmeter, the PWM servo controller/chips, the stylus servo, the base horizontal level indicators, etc.). I also desire implementing the regulator due to some of these items being subject to damage in case of power surge or backup battery high voltage (up to 14.5v). Also, instead of regulating several devices (at 12v), I designed it all with the implementation of a single regulator to begin with, designed to be less than 12v in order to accommodate battery depletion. (some of these circuits/items DO get further regulation anyways, and everything works off 10v, and my wallwart is 10v). Thanks for the resistor and wattage values! Again, the frequency is pulses per second, not per week, and 1 week is circa 604k seconds, so if I miss ONE pulse EVERY second (even though it's divided by 100 and geared down), my math reflects 1.45 minutes per week <8.73 degrees on the drum> (with a frequency counter), or 14.5 minutes per week <87.3 degrees on the drum> with my cheap 3.5 digit multimeter. The 5v astable may not vary (much) with voltage, but as previously stated, the servo momentarily pulls the draw up to almost 1.7A when it is actively drawing on the drum (normally the entire device's circuitry is a couple hundred ma), and the 9.6v servo needs regulation. Another big point also (as already noted), is that I will have a much longer battery backup by having designed it all to work at 10v.
I would gladly do the TO3 variable reg, but it's so darned expensive ($23) compared to a few 7810s or a 7810 with the passQ. My "simple" question was, is increasing the 7810's capacity (available current) possible, while whatever voltage it sits at (it could be a few tenth's above or below), it would at least remain at that specific value so once I tune the astable, it definately won't be affected by higher draws (the servo) and will therefore keep an accurate timeline on the drum's weekly graph paper. So, anybody w/o the TO3? How 'bout anybody with the TO3 at 10v (the circuit) ??
My thread is getting old, and too complicated !!! Maybe I'll excite you all with a few pictures of this electro-mechanical behemuth...