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Everything posted by jstevenperry

  1. Not a robot arm: it's a Trek 5000 road bike. The scope is a Tek 2246, 100 MHz, 4 Channel.. The PSUs are (from l to r) 50 V 1-3 A, 15 V 1-3 A. It's a cool shop. I like it. :-)
  2. Here's my lab (it's got some other stuff in it too:-)):
  3. Thanks for the link. The motors I want are out of stock :-( but the prices are good (even after conversion from Euros to dollars). I'll check back with them...
  4. They make 'em smaller. Here's one that's 2/3 the size of the one in the link I sent, but costs $1 more each. http://www.mpja.com/productview.asp?product=12342+MD. The millipede project specs call for 16 of these motors. I was trying to keep the cost low. --s
  5. I found some of these pager motors here: http://www.mpja.com/productview.asp?product=12343+MD
  6. Ah, heck. Don't sweat it. I was really just giving MP (the moderator) a little jab just as a little joke. Welcome to our forum!
  7. There are a lot of great articles on this site. Start with "articles" from the main page, and especially this one: http://www.electronics-lab.com/articles/basics/theory/index.html. Plus ask questions in the "Electronics Chit Chat" forum. This section is specifically for questions about the projects listed on this site. MP will probably be by later to break your knee caps for posting this question here :-). Don't worry, it's happened to many of us. Good luck!
  8. Okay, cool. Well, I have seen vibrating motors in the various electronics catalogs. So now I know what to look for. Thanks.
  9. I have a question about the millipede project (http://www.electronics-lab.com/projects/games/002/index.html). What the heck are "PagerMotors" and where do I get them? Thanks!
  10. True, but they have an extensive selection of identical footcare items ;-)
  11. It took 2:22 on my 3GHz HP nx9110 laptop. 1GB RAM.
  12. A 15W soldering iron is fine for most PCB applications. I have one from Radio Shack I bought for about 8 bucks. I've replaced the tip once. It's been a good soldering iron.
  13. I got it now. Thanks for the help. The only reason I decided to use a 7408 is that's all I have on hand. Thanks again to audioguru for the help. Somehow all of the great advice in guru's posts boiled down to "connect a 270 Ohm resistor between each input pin on the TTL Gate IC and ground." I've posted a more detailed explanation with a picture on my blog. http://jstevenperry.com/blog/?p=37
  14. Okay, I'm just going to have to play the "I'm an idiot" card here and ask exactly what the heck to do to wire up this 7408 AND gate. I've got +5 VDC going into Vdd, and Vss wired to ground. I want to use as inputs +5V or nothing. However, it doesn't seem to matter what I run in, since there is a mystery voltage on the input pins (even with NOTHING connected to them). Audioguru suggests using a pull down resistor to pull the inputs to about .4V, and I'd be happy to do that, but don't know what to do. I've googled my fingers off trying to find a circuit diagram to show me exactly a properly wir
  15. Thanks, guru. I'm recently getting back into electronics after a long break (since college - about 15 years). I discovered after I purchased 10 ea. of the 74xx series (AND, NAND, OR NOR, XOR and hex inverters) from Jameco that they're old, cantakerous TTL gates. That being said, you're saying some stuff that I don't get. I guess it's the "pull it down" comments that are throwing me. What do you mean? How do you "pull down" voltage? Throw it across a resistor? There's no CMOS gate involved in my circuit (that I know of). Basically, each input to the AND is a 5V input. I figured (naively,
  16. They're electromechanical, and work just like the picture Ante posted (except the pic he posted was for a 16 key, but conceptually no big diff...a 4x4 matrix versus a 3x4). The problem I'm having now is my AND gates (to produce a signal that corresponds to the exact switch in the matrix that was pressed) are doing weird things. I've posted that to a new topic, so not to pollute this topic. To me, the question I had regarding the 12 Key Matrix encoded keypad has been answered. Thanks to all for your replies!
  17. In building another project I need to whip together some AND gate logic. Basically I want to produce high output if and only if my two inputs are high. Easy stuff, right? Everything seemed to be going well, but my output wasn't what I expected. In diagnosing the circuit (I stripped it down to the simplest circuit that reproduces the problem - see attached JPG), I noticed that there was something fundamentally weird going on. Here's the setup: Circuit powered by 9V battery, running through a 7805CT +5VDC regulator (to power the 7408 gate). Nothing else interesting related to this problem. the
  18. Thanks, Ante. Then combine the output pins on the keypad with some AND gate logic and I should have it, right?
  19. 1. Size of the board (number of 5x rows of holes, and the number of +/- bus holes) 2. Price 3. Number of power connections Other than that, I don't know really what else to tell you. Breadboards pretty much are all the same except for the above 3 things.
  20. How old is your computer, and when did this start happening? It's probably nothing. Or you could be the subject of an FBI probe. Maybe even Homeland Security. Just kidding. It's probably just your neighbors. ;-) Nah, relax. You probably have nothing to worry about.
  21. Breadboards are fairly cheap, so you can look in a lot of places. I have two. One I bought at radio shack for about $23, and another (twice as big as the one from Radio Shack) that I got from Jameco that was twice as big, and a few bucks less. Throw in a set of really nice jumper wires, and you're good to go. Here are some links. Board: http://jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=20773 Jumper Wire Kit: http://jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&prod
  22. Sorry to hear about the cold. Here in Arkansas it is NICE. 63 degrees F today. Happy New year!
  23. Does anybody have a good circuit diagram for how to hook up a matrix encoded keypad. It doesn't have to be 12 key, that's just what I have. If, say, you have one for a 16 key, I can extrapolate. I am trying to get this sucker breadboarded and it's driving me crazy. I's appreciate any help. Just for fun, what I'm trying to do is hook this keypad up in such a way that when I press a particular button on the keypad, a corresponding LED lights up. But it's not working, and I think that I've just got the wrong picture in my head (I'm not working from a schematic, just from what I think I know abou
  24. I agree that systems which produce code are error prone and tend to have a bit too much trust put into with them (usually by the bean counters). You da man....
  25. Actually, $690 is a lot to pay to program PICs, considering they only cost a few bucks each. Oh, wait, you were being sarcastic. That's so funny!
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