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Posts posted by MP

  1. 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.


  2. 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.


  3. Well, that question doesn't make any sense. I guess it was an attempt at insult or avoidance?

    I noticed you avoided my last question. The reason for this question was not insult. I was told that you do not have a degree. That you are a retired Stereo technician proclaiming to be a theory expert.


  4. In another topic you asked why a member would email me instead of you when they found a problem with a design you were involved in. Look at this thread. The reason should be perfectly clear. You have exhausted this subject.

    Everything you use in normal everyday life uses this same principal. Pulse a cheaper motor with DC pulses so that you do not have to incorporate a more expensive higher voltage/current rating motor in the design. It does not hurt the motor. It does not hurt the micro.
    I am finished with this. Do you actually have a degree in theory, or is this a self-proclaimed title?


  5. I recommend the AtTiny2313 for a simple project like this. It has an internal oscillator, so you don't have to buy a crystal or resonator.
    The data sheet is here: http://www.atmel.com/dyn/resources/prod_documents/doc2543.pdf
    I am not sure where you live, but Digikey.com has them in prices ranging from $1.30 to $2.25 in qtys of 1 each. You can get the free version of BASCOM AVR at www.mcselec.com
    The free version only has limitation on the amount of code that can be written. That limitation is more than what the 2313 is capable of. In other words, you will never need to buy the purchased version when using this chip.
    The LEDs can be connected to the output ports with a resistor in series. The port iwill output 5 volts when in a high output state. Just use ohm's law to determine the resistor. I use 4K7 for most projects, but you can use a smaller value to get a brighter LED. Just don't exceed the manufacturer's specs for the LED and don't pull more current through the chip than needed to accomplish your goal. The switch can be any momentary switch connected from the input port pin to ground. Also tie a 4K7 resistor from this port pin to the 5 volt buss. This keeps the port in a high state until you press the momentary switch. Then the port is momentarily in a low state, and then high again. You will base your code on this principal.
    Let me know if you need more information.


  6. Your easiest solution is to use  microcontroller. Although this sounds like a big step, it really is not for such a feat. You can even use basic to program the chip. One inexpensive solution is to use an ATMEL chip (around $7) and the free version of BASCOM AVR program. You do not need a programmer since AVRs can be programmed in-circuit.
    You can use an 8 pin port as output, which means 8 switches. 2 pins on another port can be used for the control buttons. Call then switch A and switch B. Yuo can program the micro so that whenever switch A is pressed, the output port equals the output port + 1. You can progran the micro so that whenever switch B is pressed, the output port equals the output port - 1. Other combinations are also possible. Since you are using a micro, you also have the capability to add an LCD display and to send something to the serial port if you wanted. Since you can program a micro many times, it is easy to make a change in the program should you decide you want to add a feature, etc.


  7. Thanks MP !!

    can you please attach or tell me the difference between the one i did and the one on your site ?
    i found it on this site of course....  ???

    The one now on the site is designed just like any other square wave inverter. The one you built is designed just like an audio amplifier with heat generating resistors to ground. Something you would expect to be designed by a stereo technician or audiophile. It consumes way too much energy from the battery. Others have emailed me to let me know they had to make serious changes to get it to work properly for them. It was after these emails that the one you made was removed from the site.

  8. Photoar,
    I got several complaints about the circuit you built. It is built like an audio amplifier and does not apply the same rules as all other square wave inverters. Other members have gotten better results by removing some of the power robbing and heat generating parts, making it more like the one which is now posted on our site.

    However, if you are not getting a data stream from the CD4047, you have either pulled too much current through it or you have connected it wrong.


  9. I noticed that you use 100 ohms base resistors for the transistors. Then the max output current rating of the PIC is is exceeded. Its absolute max output current rating is 25mA and yours is 43mA.

    This is not a steady DC voltage. It is a pulsed voltage. It is calculated differently. Your output is a factor of the on state vs the off state.

  10. If I understood your original post correctly, you are wanting a device that will send out gray code to a set of LEDs. Gray code is what you send to a stepper motor in half step mode. It looks a lot like binary code. Each time you have a pulse to the stepper controller, you step to the next sequence. Using a 0 for OFF and 1 for ON, visualize 4 LEDs. They are all off to start. Call this 0000, next, 0001, then 0011, then 0010, then 0110, then 0100, and finally 1100. This is what causes a stepper motor to spin.
    If I am correct that this is what you are actually building, then you only need a stepper controller. Instead of a clocking device to step the sequence, you could just use a switch to send the pulses.
    Something like this might work better:


  11. x_dadu,
    You do not need more than one LM317 to do this. You can use your LM317 regulator to excite the base of a power transistor. This will allow you more current from your power supply. If you need more current than what this allows, you can certainly parallel the power transistors as long as you add a small resistance from each so that the load is shared equally between all of them.


  12. I have removed at least two posts from you in the Projects Q/A forum. Here are some guidelines that will help:

    1. Post in the appropriate forums. (Projects Q/A is reserved for discussion of projects that are in the Project section of this site.)

    2. Post in English. (Your post in another language in bold red type followed by angry faces was not appropriate, but I did get the message.)

    3. Do not post the same questions in multiple forums. (You have already asked this question in the Electronics Chit Chat forum.)

    Following these guidelines will also get you much better help for your question.

    Thank you,


  13. I'm a little confused here again on your description. Where are the momentaries and where are the constants? If which two contacts are shorted, where does it cause a constant connection? Are you saying, for example, that the pedal makes a momentary short on the yellow to orange or are you saying that a momentary short or press of the pedal causes a constant connection of the yellow to orange?
    If a momentary press of the pedal makes a constant connection between yellow and orange, then there is most likely a cmos latching circuit in the pedal. If you mean a momentary short between yellow and orange, for example, makes something happen, then there is a latching circuit in the amp. If this is the case, it is a little more difficult because you do not know what you are connecting to.
    Let me know which it is. I assume you want to duplicate the original pedal?


  14. I wouldn't want to make any guesses since I do not know what is on the other side of the plug. In other words, without seeing the schematic of how this is wired up in the amp, there are too many variables. With a schematic, you could make a very elaborate switching control.
    If you just want a switch that will allow you to short yellow to orange in one positon and red to green in the other position, you can use a 4016 cmos switch IC to do this. You will need to add a few components to keep the switching action from popping. However, this is simple to do. Let me know if this is what you are wanting to achieve.


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