At 12 volts which is what I am planning to use for this circuit, it should have plenty of drive as well as rail to rail. I am planning to drive the transistors with 20ma which should be plenty to turn them completely on and off. I tried to be up front what's the results of my circuits so we shall see.

 

Hi Wendy, your circuit idea is fine.
I see that with a 12V supply the Cmos 555 can produce an output low of 50mA (!) at 2V max and produce an output high of 10mA at 10.5V minimum. Then it packs a lot of current when its supply voltage is 12V.

 

I am my own worst enemy on this project, between using parts that are in the wrong values and other brain farts, it has taken a lot longer than I anticipated. The 7555 would not come up with a clean square wave no matter how I tried here is the wave form I got with an unloaded circuit both the resistors to the transistors and the transistors were removed.

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the second image is a stock 555. I still need rail to rail to make the square wave 50% symmetry. But I can work with the 555. So it is back to the drawing board, I will relay this board out try it a different way. More to come. I have think I have finished most of this 3D part of this project, it is good to get back to the electronics portion.

 

I still need rail to rail

Put the discrete inverter from post #7 on the timer output.

 

I did I wanted to remove the load from the 7555 circuit to see if that was causing the distorted square wave. The 7555 waveform shown above is without a load. If you don't get a good way for him to begin with how are you gonna get it to work later? Even though it is a power hog I am going to try using a 555 instead.

 

I hate to ask, but did you check your scope probe compensation? The waveform looks very much like an under-compensated scope probe.

 

I just knew someone was going to bring that up. Yes I did compensate the probe since it never goes anywhere else but this is still a scope you only have to do it once (because I knew this issue would come up I checked it on the scopes built-in compensation output). The only difference in the two way forms shown is the chip used, one is flat and the other is not. I have got a new layout drawn, when I have gotten it implemented I will post the results.

 

The Cmos 555 has a fairly low max output current that takes time to charge the high gate-source capacitance of the very high power Mosfets. The old original 555 has a max output current much higher than Cmos 555s.
The breadboard has problems:

 

That design is history, I'm using some techniques I have developed in the past for the next iteration.

 

Final iteration, I'll let you know if it works. If it does I'll transfer to a protoboard solder board, box it up and put it as a completed project.

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What kind of range did you get from this?

 

Haven't made the current version yet, The upcoming complete project will cove this in detail. I've made many other revisions.

 

Ohhh...ok, I'll have to wait