Take a look at this thread, he gives good feedback, and his project is very similar to yours.

http://forum.allaboutcircuits.com/showthread.php?t=24835

 

I saw that thread and have been following it for the past couple of days

 

Bill, on your breadboard diagram, would I be correct in assuming that the wire on pin 5 is supposed to be on pin 6? I think I may have seen that mentioned somewhere before but I wasn't able to find it again.

 

OopsSmoke,
You are correct; that jumper should have originated from pin 6 instead of pin 5 (move G12 to G11).
In this particular application, pins 6 and 2 need to be connected together.

There is also a missing jumper between pins 2/6 and the + side of the capacitor. That could be corrected by inserting a short jumper between C7 and C8.

Here is the drawing with the abovementioned changes:

 

Opps,

It shall be fixed imediately. Thanks for the feedback.

Your illustrations are about to crash.

 

I made the change above, but I think my 555 may have bit the dust. About 1/3 rotation on the pot will sometimes give me 9+ volts, other times I'm just getting 0.2ish. This is using a 100K potentiometer. I don't have a 10K on-hand at the moment.

I took the LED's out of the circuit, because I only had 10KΩ resistors and was barely getting any illumination from the LED's.

I'll have to wait until pay day next Wednesday to get more parts. Is there any way I can test my 555 to make sure it's not bad?

 

This project, 555 Hysteretic Oscillator, is extremely close (and has been verified). It also makes a decent 555 tester.

 

It's been a while, but I am re-attacking this. With my fresh(er) point of view, I noticed there is no transistor or MOSFET on the breadboard diagram. In the schematic there looks like there should be one, though. Have I been overcomplicating this the entire time?

Thanks!

EDIT::

Therein lies the problem with staying away from a project for two months. You forget what you used to think you knew. I did find something interesting, however. I have the leads of my multimeter hooked to the leads where my motor would be connected according to the schematic, but when I connect the motor to the leads, I get a zero voltage reading on my multimeter. Both the multimeter and motor are connected at the same time. Is this to be expected? Does this shed any insight on my problem?

 

Are you using my layout, or something else? The meter would only be a problem if it were in the current range, voltage range is passive.

 

Yes, I'm using your layout.

As for the multimeter, I'm not sure I know what the difference is. There are two voltage settings from what I can tell. One has a V with a ~ over it and the other is a V with a line over it. I won't be able to check the documentation on it until after work. The setting I had it on was the one with the ~ over it.

Also, I found that I was having different results with different MOSFET's. I was using a TIP32B and an IRF something or other (another thing to look at after work). With one, don't remember which, the hobby motor would run and both LED's would light up. With the other, the motor wouldn't run and only the red LED would light up.

 

That is the AC scale, with a sine wave it will read RMS voltage, and steady DC will not show on it. You'll need the DC scale.

 

I was mistake, I have been using the voltage setting with the line over the V. That would be the DC, right? Anyway, the MOSFET that seems to give me something instead of nothing is an IRF640. Will the MOSFET or transistor itself make a difference in this circuit? Also, I guess I should mention that my potentiometer is a 100K Ω, 3/4 turn. I recently noticed that some schematics are using multi-turn pot's. I think now I'm just trying to rule out any possible component problem.

 

First thing is check your batteries (or wall wart) with the meter, you should get something. I wouldn't worry about multiturn resistors, I went with a single turn unit (even though I had used a 10 turn in the past) so the effect would be noticable.

In my experiment I am planning on using the large capacitor to show the effect with the LEDs. You might consider doing the same. Once the duty cycle variation has been established, then replace it with a small capacitor, which will make the motor happy.

 

I apologize for bringing this post back, but I wanted to give a progress update.

Ultimately, I suck. Instead of sticking it out and finishing developing the circuit, I found another old drill and hacked the trigger assembly, replacing the trigger with a potentiometer while keeping the directional switch with it's mysterious circuit untouched. The only problem is that the pot has a very limited range that runs the motor. This was a move born from desperation and frustration, not to mention the year working on it off and on.

Funny story, I took the drill that I hacked the trigger from to my local electronics store and told the guy that I wanted to make it run. His reply was "Good luck." Apparently they draw a lot of current and he recommended PWM or a thyristor.

I appreciate everyone's help and tolerance of my lack of knowledge. Time allowing, I have other projects that I'm working on and hope to learn from so that I might eventually give something back.

Kevin

 

No problems guy, whatever works.

 

Well a year-long project is hard to stick with.

This is why it is best to start with a kit or something less complicated so you FEEL good about getting it done.

That feeling of accomplishment can hold you a long way.

If you start to get stuck on a project, order a $10 kit and get that together, refill your "I can do it" reserves and get back to the project.

For your drill, it seems that you are using too small of a pot for the job.

A larger pot will give you a broader range of speed.

 

Kits are nice for the accomplishment feeling that's for sure. The problem is finding a kit that suits your needs.

I do like what you said about filling your "I can do it" reserves. Finishing any project, kit or not, can be just what you need to get the juices flowing again.

The pot I am using is a 35K, I think. I tried what I thought was a 100K and had similar results. Maybe I'll give it another shot and see what happens.

K

 

You'll note my projects are very simple. I plan on increasing complexity as I go along. That is basically the intent of the experiments volume.

You have any problem reading the illustrations I post? (Yes, I'm looking for feedback).

 

Actually, Bill, I have found all of your illustrations exceedingly helpful and easy to understand. I especially like your breadboard layouts. My experience primarily being from your inputs on this thread and your 555 PWM Oscillator page. Since I still consider myself a newbie, the only illustration I see that's missing is where it goes from schematic to breadboard to perfboard. I'll tell you what, one of the biggest stumbling blocks I've had is going from a breadboard layout to a more permanent perfboard layout.

 

Are you wanting the PWM to breadboard (the kind with pads)? What schematic exactly?