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  1. MP1

    current limiter and stepper motor ramp generator

    You actually have to add delays in between the data bits sent to a stepper as it is not able to work at speeds as fast as a computer or microprocessor is able to send data. So when you want to change the speed, you just change the amounts of delay in between the step bits. MP
  2. MP1

    Need help for a heartbeat detector!

    birdbird, will you please quit writing in code. There are members of this community who do not speak English as a first language. Interpreting your posts is impossible to these guys. MP
  3. MP1

    0-30 Vdc Stabilized Power Supply

    Maybe his neighborhood is a little more regulated than yours ;D MP
  4. MP1

    New section.

    It is easy to ask for more strict moving of posts, but many times the posts are still related or use references from an earlier post. When you start cutting this up, you end up with two sets of messages which are not very readable. I have moved many posts and deleted things that should not be in...
  5. MP1

    COMPUTER SYSTEM

    It really depends a lot on the vintage, etc. post a photo and someone can mark it up with descriptions. MP
  6. MP1

    AAA Battery Charger

    Maxim does have some nice battery charger chips. They run a little more than $2 each to buy direct from Maxim. You might have a hard time finding the DIP package. SOIC is the most popular. The nice part of using Maxim's charging ICs is that they have plenty of supporting documentation for their...
  7. MP1

    detector prototype

    Badai, In Eagle, you must choose the correct IC package for the ICs used. You should be able to find most common op-amp packages in the "Linear" library. The IC-Package library is there in case you cannot find something that works. Pay close attention to vcc,vee,vdd, etc on the library package...
  8. MP1

    SERIAL PORT

    On a parallel port: Data bits D0-D7 connect directly to an octal tri state latch and an octal tri state buffer. These are 74LS374 and 74LS244. Pins 2 through 9) The Ack, Busy, PE, Select and Error, pins 10, 11, 12, 13, 15, go to another tri state buffer. The ack line also connets to IRQ7, Pin...
  9. MP1

    CMOS power use?

    You just contradicted your last post. Capacitance is one of the things you are adding to the circuit by sourcing lots of other chips. Just laying them out on more circuit board space effects capacitance. Something must power these chips. There will be differences in current consumption for all...
  10. MP1

    detector prototype

    To complete the board layout, you can use a 2N3904. Then you can use any transistor with the same package type and pin out. You should get the data sheets and compare the transistors listed by audioguru and choose the closest one that is available to you. Good to hear you have Eagle figured...
  11. MP1

    SERIAL PORT

    I build a lot of equipment which uses the serial port. I have shorted the pins of the computer port many times with no incident. I have never in many years had or seen such a problem. Connection of pins 2,3 and 5 directly to equipment is safe. It is when you have one of the low powered laptops...
  12. MP1

    detector prototype

    Badai, I congratulate you on your motivation to learn Eagle. Once you have used it for a while, you will wonder how you went without it. For the diode, you can use the 1N4007 package to get a footprint that will work for you. You can use any 3 pin connector for a potentiometer if it will be...
  13. MP1

    CMOS power use?

    What you are looking for is a fanout spec, but output pulses to 14 other gates? You must be ganging them up to get this from a quad output gate. And then, you must also be powering the other gates, too. Have you thought about just hooking up a multimeter between the chip and the battery and...
  14. MP1

    Electronic Stethoscope 2

    I was refering to you, the author of the circuit...My mistake, then. I guess I figured you would not post a project without making a prototype or at least simulation because you made such a fuss about there being a project on this site that Aaron Cake did not actually build and test himself...
  15. MP1

    Led display Digital Voltmeter mod

    Those who have the highest interest in that project probably have "notify" turned on which means they get an e-mail when a new post hits that area. Starting a new topic does not notify anyone in the original thread. This is why it is best to continue a topic rather than to start a new one about...
  16. MP1

    COLOUR T.V

    uhh....research, yeah, that's it. It is a productive tool. ;D ;D ...actually, the TV and refrigerator are not in the shop. Only the air conditioner is in the shop. ;) MP
  17. MP1

    Electronic Stethoscope 2

    He did not build it. He simulated it. There are no pictures. MP
  18. MP1

    COLOUR T.V

    My TV, and the air conditioner for my shop, and my refrigerator all have a 3 prong plug. 8) MP
  19. MP1

    Help needed for storage device

    When you do this, there is no longer a need for the original project. You will not need the digital voltmeter circuit. The microcontroller with an ADC will do it all. MP
  20. MP1

    Circuit Design Help

    Jesteban, For a digital to analog converter, you are converting a binary number to analog. For example, binary #s in a 5 bit word are 16, 8, 4, 2, 1. 16 is Most Significant bit (MSB) and 1 is Least Significant Bit (LSB) in your 5 bit binary word. Therefore, you will use resistor values MSB = R...
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