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MP
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Posts posted by MP
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Your usb port is most likely part of the mobile phone circuitry. I doubt that the cable will be much more than two data lines and voltage + and -.
Is there circuitry in your cable? Without a pinout of the cable or more information on the phone, I can only make a guess.
MP -
Here is a link that might be helpful:
http://geek.scorpiorising.ca/windingtransformers.html
MP -
I would spend my 10 to 12 dollars on an LPT card for the computer. USB adapters are ok, but they rely on a virtual port built in the software on the PC. These ports do not come on inexpensive computers because computer manufacturers think we only use this port for printers. It is a cost cutting effort. Since everyone now has gone to USB printers, there is a misconception in the Industry that the LPT ports are no longer used, and thus, a waste of hardware to add them. I would never own a computer without serial and parallel ports. I would always factor in the few extra bucks to purchase an additional PCI buss card to activate these ports.
MP -
Heat shrink tubing is pretty robust. You can actually touch it to the solder iron without harm so long as you are not touching it for long. However, this method makes for some pretty ugly wires. The solder iron tends to discolor and melt the outer surface of the tubing.
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There seems to be a misconception that serial to USB conversion is just an added circuit to the comm port. You need to completely change the signal and add drivers to the PC to make a virtual comm port for the new signal to run on.
Here is a link that will help get you going. You will find the dedicated chip and the license free software that is needed.
http://www.ftdichip.com/Products/FT232BM.htm
MP -
Hopefully all can figure it out now that the instruction is out there. There are also the numbers at the top of the message boxes, but that only allows you to go back a few pages at a time.
Also, when you browse around and want a quick bookmark to a thread you will want to come back to, you can just copy the info from the address bar and save it in a text file with some type of description. Much faster than a search.
Have fun!
MP -
This topic has been moved to Electronic Projects Design/Ideas.
[iurl]http://www.electronics-lab.com/forum/index.php?topic=7335.0[/iurl] -
Why do we need a fix for this? There are a fixed number of messages per page. In the address bar above, see where it ends with .../index.php?topic=6816.0....
This means you are on the first page. For the second, it would end with ../index.php?topic=6816.14...for the third page, .../index.php?topic=6816.28...etc. Go to the first page of a long thread and try this to get you to the page you want.
MP -
additional posts regarding theory discussion has been moved to the Theory forum.
We were getting a little off-subject here.
Thanks,
MP -
Sure. I just get tired of the scare tactics to newbies....you will fry this if you don't follow my instruction....etc.. but then I get emails from those who have built the originals with no problems, grumbling about what they feel is a false posting on this forum.
Projects Q/A is primarily for those who are actively building these projects. Not for theory statements or overall attempt at re-design in one's head. We have a forum for Theory discussions.
Thanks for your input.
MP -
There is no guarantee on any schematic you find on the Internet. That is why there is a discussion area for Q/A of the projects in our project section. Most projects which have a substantial conversation thread will also have a link from the project page. The Eagle version is ok. Also, I am pretty sure corrections in the original project were already made my mixos. This should be clear if you read through the pages of this thread. I uploaded the Eagle version so that members who wanted to make a board had an easier method to do so. As far as your comments about the power supply project, many members have built the original and have had no ill effects. The member who has posted the changes in that forum has not built the device, so I will have to take the word of those who have built it over one who claims to be a theory expert.
MP -
You have data bits on this line, which are just pulses. Use a scope or other device that will allow you to watch the pulse stream and compare with the other ports. By working your way through the circuit, you will be able to find the place where the signal stops.
MP -
I'm looking for a drill press design for drilling pcb using a dremel, any ideas?
I think this has already been done some where, but why not disscuss it? Besides, It kind of dissapoints me that the hardware section is kind of empty... :'(
Dremel makes one. The dremel fits in it perfectly....or did you already know this?
MP
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Forgot your second question....
You can find out which windings are connected by using an ohm meter. The windings will read like two resistors connected in series and the center tap is half the resistance of the ends of the coil.
Hope that helps.
MP -
Yes, in some cases, you can run a stepper directly from the micro. However, your micro port pins are limited on current and if the stepper all of a sudden draws more current, poof! goes the micro.
The ULN2003 is good insurance.
MP -
Zero ohm? All wire has some resistance. You can look at a zero ohm resistor as a value with not enough resolution. Add the decimals places and you would have some small value there.
MP -
In a search, I found medical clinical digital thermometers with accuracy ranges from 0.1 deg C to 1 deg C. You can pretty much choose how accurate you want it to be, then spend accordingly for the parts.
MP -
Hi all,
can some one, specially circuit designer, give a complete part replacement?
new users (like me) can't read 70 pages?!
The circuit designer's list is the one that is in the project. The designer has made no changes. The list above are modifications suggested by a forum member.
MP
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This chip would not power steppers needed for such a project. You need something like a L297 and L298 combination to get enough power. Steppers are rated in torque. You should be able to calculate the motors needed from the torque rating if you know what it is. Actually, this is something you will want to figure out before you start this project. Otherwise, you might end up with a completed project that stalls when feeding the wood into it.
As far as keeping with accuracy, I would suggest a lead screw connected to the stepper and a couple of rods with brass bushings to keep alignment. The tolerance of the bushings and looseness of the thread would be your maximum tolerance.
MP -
That is not actually true. The first step is to check the data sheet for the relay you are using. If you are using a 5 volt relay with a 6 volt maximum allowed, you are slowly killing the relay by using 6 volts. You also have the worry of surges on the circuit causing the voltage to fluctuate. In this case, you would see a premature failure of the relay when the voltage passes the max rating. The only reason that a circuit might appear that you need more voltage than specified of the relay is if you are asking for too much current through your relay. Then there is a voltage drop. In this case, the correct solution is to get a relay that will handle the current required and stay with the correct voltage rating.
MP -
It is rare to see anyone go through the trouble of making a project and then posting it if it does not work to begin with. In most cases, I see simple things like component drawings backwards, a line in the drawing that gets connected to the wrong lead or is missing a connecting dot. These are all drawing semantics. Keeping in mind that the original project works, you can easily get past these small details. It also builds knowledge. For those who are in school, keep in mind that when you are working in the Industry, these are things you will see on a daily basis. Drawings are hurried, and since the Company does not hire just anybody off the street, it is recognized that you will have some technical knowledge to begin. It is all a part of everyday electronics troubleshooting. Got a drawing with a backwards part drawn into it? Turn it around and build the device. Look at all the Smart Kit drawings...perfect example of this. The kits work, but not always the way the schematics show them.
Thus, I repeat: How do you know the project does not work when you have not built it? You only know that there is a problem in the schematic. From a manufacturing point of view, these are two completely different things.
MP -
In my country (italy) 2N3866 is very common... and costs about 1 euro.
1 euro is approx 1.25 USD, so the price from Mouser is pretty close to what you have been paying for this part.
MP -
The same author has another project using 74A ICs that also doesn't work."
How do you know these projects do not work if you have not built them and rely on comments from someone else who has also not built them? Most projects have links to the author. Why not contact the author directly? mailto:[email protected]
MP -
You're not going to see electrolysis effects for a long time. The chlorine would have a bigger impact than electrolysis. In fact, chlorine is going to be harsh on a reed switch. Also note that a floating magnet setup will act erratic. Instruments that use a reed switch and magnet have the reed switch fixed and the magnet movement is controlled so that it is always the same reed switch/magnet interface each time. When you do not control this mating of the components, you have erratic switch action. Best to use a float ball with an arm and use the controlled pivot point of the float arm for this.
MP
USB to LPT Adaptors
in Electronics chit chat
Posted
Even easier....you get the PCMCIA card for it.
MP