MP

No, it does not. But I AM a programmer.... ;D Good luck with your project! MP

Where in Rod's post did he say he was specifically refering to a DC motor with brushes and a commutator, or a brushless motor with an electronic commutator? Seems you have hijacked another thread to discuss your own subject.... In fact, it seems that you have scared Rod away. He hasn't posted since you started digging on him. MP

With a quick look, C1 should be a much larger value. Also, the voltmeter has it's own setup. It must only use a samll voltage form the larger supply. For example, the voltmeter will have input resistors that scale down the voltage so that it is really only looking at approximately 200 mA. So if you have not set this up correctly, you will get a full scale. Hope it helps. MP

The guy in the tutorial had a hell of a time making this work. You go ahead and make it any way you want, audioguru. Could you please explain the code in the link you have cited as the reason you disagree with me? oops. Sorry. I forgot. You do not know how to program a micro. But going back to the original comments: Rod.Rahul was told that PWM was required. As I posted above, Rod, you do not require PWM for speed control on your L298. You can go ahead and use the PC control that you want to use with simple pulses. This can be through serial or parallel ports. My automated drill uses this principle. I use the up and down arrow on my pc keyboard to control speed of the feed. No PWM. MP

Tkjas, you posted in the wrong area. You should have asked this question in the microcontroller area where programmers would have given you an answer. Here is a link that will help: http://www.embedded.com/story/OEG20010221S0034 Best of luck! MP

Without looking at your diagram, I can only guess. But it sounds like you just need a split supply. You do not have to use the same common for two circuits. There are many designs where the common for one section of a circuit is floating at a different potential than the common of the other circuit. Looking forward to seeing your diagram. MP

Posted in wrong forum. Go to [iurl]http://www.electronics-lab.com/forum/index.php?topic=8128.0[/iurl]

Posted in wrong forum. Go to [iurl]http://www.electronics-lab.com/forum/index.php?topic=8197.0[/iurl]

Posted in wrong forum. Go to [iurl]http://www.electronics-lab.com/forum/index.php?topic=8272.0[/iurl]

In looking at your schematic, it seems that you are powering and also grounding your motors through the relays. Perhaps I misunderstood which lines were which. However, if this is the case, I would advise that you use a permanent ground or permanent voltage connection and only use the relay for the other lead. You only need to disable one connection to the motor to stop it from running. This will reduce some arcing in the relays and the circuit will last longer without the need for maintenance. Next, you should probe the circuit from the motor back to the digital circuit to see where the voltage loss becomes apparent. I would use a better design for the transistors used as a switch. Look closely at this area when you are probing. MP

Just my 2 cents on the subject. Since a lot of this is based on field of study and individual taste, there would be so many posts that it would at some point not be very helpful. ...and of course, then you would have those members who want to argue about what is best, and that someone else's suggestion is not good, or that someone is wrong......etc. MP

Oh, yes it does.....I think you have once again become argumentive on a device you have never used....Your statements would be true if you were feeding the signal directly to a motor. I think both of you have missed this detail. We are discussing the input of the L298. Not a motor. In our discussion, we are feeding a clock signal directly to a L298, which runs on TTL clock signals. We are not feeding a direct voltage to a motor. If you are going to use PWM, you would have no need for the L298. It is all in the data sheet. There is no mention in the data sheet about changing amplitudes of signals or PWM. I have designed a good share of automated equipment with the L298. I'm not guessing, here....oops!, I mean this is not "Theory" ;D MP

Faizanbrohi: We are discussing how to get good results with photo etch. Not glossy paper. There is another thread about using your method. You should post in that thread. By the way, I totally disagree with your comment. There are many tight designs where glossy paper just pushes out crap. Works well for the hobbyist, but more professional artwork requires a more professional method. Mik3ca: Sounds like you are on the right track. You have brought the exposure time down from one hour to 20 minutes. Your developer ratio might not be the problem. The black light might have been over exposing your artwork. You might want to try another board with a 10 minute exposure time as well. My exposure fixture has four of the black light tubes like what you have. This is only so that I can expose a 12" x 12" board with no problem. At the height that I mentioned above in a previous post, I never go more than 3 minutes. Just for your own knowledge, you might want to see how short of an exposure time you can get. MP

Excellent! Thanks for posting. MP

No, You don't even need to change the width of the pulse to change speed. No, I am not talking about anything that has to do with "Pulse WIDTH Modulation", including any of the projects. I am talking about basic TTL clock signals that have been around for years. Simple. Change the clock speed and you change the speed of the motor. The signal is a 50% duty cycle and the pulse width is never intentionally modified. PWM or 'Pulse Width Modulation' works on the principle of changing the ON time vs OFF time of the individual pulse. This is not needed. A simple clock pulse stream of 50% duty cycle will vary the speed of this chip easily when you change the speed of the clock. When you change the speed of the clock, this is not PWM. Thus, PWM does not even come into play. I hope this explains it in a way that you now understand. MP

You don't even need PWM for speed control since the input is looking for a TTL signal. You only need to change the speed of the pulse stream. MP

The L293 or L298 do not need PWM control. They are made for use with standard TTL signals. If you had looked at the first paragraph of the data sheet, you would have known this. Read the data sheet. MP

You would have to experiment around to see what the maximum exposure time would be. The light you are using is not very efficient. Do you have a place in your area that sells party supplies or lights for black light posters? There are many places where these are available. They really cut down the time for exposure. You can also get them in the round bulb type if you do not want to change your setup. When I built my system, I performed the test that I mentioned in the last thread. I killed a couple of boards but found my perfect height and exposure time. The problem with slow exposure is that the light will find any small imperfections after time. The faster you can expose the artwork, the better. MP

wow, 1 hour is a long exposure time. I usually never expose for more than 3 minutes. Perhaps this is why you are getting different results. I use a light table that has 4 of the fluorescent "black lights" in it positioned approximately 120 mm above the glass. You do not need dark black transparencies. On lighter work, you can use less exposure time. This is where the spacing becomes critical. You cannot get real tight artwork with transparencies that are not dark. Try the black light method and make some time tests on the same board using a black piece of cardboard to cover the board. Expose a small area for 1 minute, then expose same area plus another section for 1 minute, then uncover another area and expose again for 1 minute, etc. This will give you 1 minute, 2 minute, 3 minute, etc. exposures. Then when you develop the board, you can find your best exposure time. You might want to switch to a better photo resist and developer. MP

gogo, Look at a computer motherboard. All traces and pads are gold plated. MP

Happy birthday, Mike! Tip a few ouzo's! ;D MP

I have never heard of anyone plating "after" solder mask. I cannot think of a good reason to do that. At best, your plating is a cosmetic in this case. MP

MOVED FROM MICROCONTROLLER FORUM Lakhan, You seem to have a problem with finding the proper forum. Please post your conversations in the correct forums. MP

To All: The project schematic is back in it's original form and is correct. Anyone making this circuit should have no problems with it's design. Thanks Kyr, for joining the discussion and adding the additional comments about your project. MP

try here: http://www.alltronics.com/cgi-bin/category.cgi MP