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Everything posted by MP

  1. Hello phinder and Kevin, I am not sure what type of power you need for these solenoids, but here is an example of controlling the mains voltage from a PC. I can't imagine you would need any more power than this for the solenoid. You can use the parallel port of the PC to set a pin high, which turns on a solid state relay. I prefer solid state relays to the mechanical types as posted in your link. You can duplicate such a circuit and use D0, D1, D2, D3, D4, D5, D6, and D7 to control 8 different SSRs (Solid State Relays). Here is an example. Click on the image below to enlarge it. MP
  2. Are you looking for something like this? http://www.tekscan.com/flexiforce/specs_flexiforce.html MP
  3. Michael, More specifically, L1 is made by wrapping (coiling) the wire around R2 until it is completely covered with the winding. This is why it says 20 to 30 turns. Different resistors will be different lengths and thickness. MP
  4. You should use the correct chip. Most manufacturers will give you free samples. MP
  5. EDY is a member of this forum. Since he did not elaborate in the project page, why not send him a personal message asking why. There is also another thread in this forum where this was discussed some time ago. You should be able to find it with a search. MP
  6. Hey Ben, The project looks nice. If it also sounds good, why tweak it? Congratulations on your achievement! MP
  7. Proview, Have you looked at the radio circuit projects on this site? Click on the "Projects" link at the top of the page or follow this link: http://www.electronics-lab.com/projects/rf/index.html. MP
  8. Use what you want, but your picture doesn't even agree with your statement. Sure looks like the more squared silver mica than the very small round ceramic to me. ;D All fun aside, the silver mica will be better. I use them in microcontroller crystal applications where more precision of frequency is required than what a ceramic will give. Silver Mica is not an "old" cap. They are widely used in everyday electronics. MP
  9. They are certainly not ceramics. With a closer look by enlarging the picture, I see these three are not all the same capacitor type. The 39 pf has a different appearance. The 100 nf caps are tantalum and the 39 pf cap is a silver mica. In looking at the schematic this also makes sense due to the purpose of each. MP
  10. The 3 capacitors on the right hand side of your picture are tantalum. Not ceramics. Collinph: I have moved all of your other posts into this thread. It only confuses everyone when you post your questions many different times in different places. Also, there is a link from the project to read the posts. These are only pointed to one place, so everyone would miss some of your posts if I allowed them to be made in other places. You can also click on the author's name in the project and ask questions directly if you still have confusion. Much of the confusion is caused when a project is translated from one language to another. Little things like silk screen imaging printed backwards is just something we have to live with when getting free projects from the web. This is part of the reason for this forum. MP
  11. This refers to the projects found on this site by clicking on the "Projects" link at the top of the page. If you need assistance with a project from another location or site, please post your question in the "Circuit General Request" forum or "Design Ideas". Thank you for helping us keep the site organized. MP
  12. Please post a link to the project discussed. MP
  13. It's easy with one of the newer transmit and receive chips such as the Linx technology chips. http://www.linxtechnologies.com/index.php?section=products&category=rf_modules You can check out the Linx website or find equivalent chips at rfdigital at: http://www.rfdigital.com/ Here is also an example of using one of the Linx sets: http://www.wrighthobbies.net/examples/wirelessdata.htm MP
  14. Mike, As rigdoctor has mentioned, there are lots of standards out there. CE is probably what you are looking for, though. This is the standard that all products must meet and have a marking before you can import them into your area from another Country. It is somewhat equivalent to the US standard UL. Most of the other standards are not governed quite so much. Many are Q/A and Customer Service standards. It is certainly hard to go through them all. MP
  15. Biffloman, Are you looking for something like this? http://www.amazon.com/Adorama-Regulated-Universal-Multiple-Connector/dp/B000AMCM5Y MP
  16. Did you also try swapping out the video card? MP
  17. You are looking for a modulo 8 counter. Look for information regarding this name and you will have what you need to send out the pulse every eight hours. The LED part is easy. You have a binary count of 1, 2, 3. MP
  18. Importance level null. Post was in violation of Forum member agreement. Content removed. MP
  19. Yes. There are some different speeds and there are some package types that work at extended temperatures, etc. It does not matter since you will use the internal oscillator. Just get the cheapest dip package available. If you were using an external crystal, you would need to select the proper one. If you want more speed, you can certainly go this route. Just purchase a 10 or 20 mhz resonator. But it is not necessary. This processor executes one instruction per clock cycle. Since the internal oscillator speed is 128 KHZ, this means you can execute 128,000 instructions per second without adding an external oscillator. MP
  20. I have moved this topic. The Projects Q/A forum is reserved for discussion of projects that are found on this site. MP
  21. Another opinion: They're awful. Better off to just breadboard something from a kit instruction than to use one of these. The springs on these kits are awful. It is easy for a beginner to get discouraged when something does not work, and on one of these, sometimes it is not the beginner's fault. Look for the different block or blox modules that snap together to breadboards. Much better. This is just my 2 cents, but taken from my experiences teaching High School students electronics, programming and CNC. MP
  22. You are right. I did not answer that question. You are telling me how it works, but at the same time, asking me how it works. At this point I see that I have allowed this thread to get away from being useful to members of the community. Thus, I will withdraw from the debate. I encourage you both to continue your education and to take a few chances on parameters that are not listed on the data sheet. When a spec is not listed on a datasheet, this does not mean it is not allowed. A datasheet is only a guide or starting point. It would be a fairly large book if the manufacturer listed all possible test parameters. It only gives you the basics. From there, you must use your own knowledge and experience, or perform your own testing. MP
  23. Some of the kit manufacturers post their instructions on the web. The instruction set usually has theory of operation in it. Is this what you are looking for? Look at http://www.kitsrus.com/kits.html and click on the pdf icon or http://www.electronickits.com/kit/complete/complete.htm and click on the name of the kit, then on the pdf file. MP
  24. Download the Bascom AVR program. In the help file, it shows how to make a cable to program the chip from your parallel port. That's what is nice about the AVR. You don't need to buy those expensive programmer boards. You just make your board, add a header to it for the programming cable and you are all set. I recommend you purchase the PDIP package. This is the DIP package with through hole pins. MP
  25. That's the course that allows you to be eligible for "Engineer in training" upon graduation, but does not recognize you as an Engineer, isn't it? Gramo: There is most certainly a difference in voltage and current output between pulsed and constant. The output voltage is not the same on a switched circuit as a constant one. Especially with varying on and off times. This is the whole purpose of PWM. Absolute ratings given in a data sheet are performed with a constant source. MP
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