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admirlk

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  1. Circuit Help

    Well, I got the first stage doing something on a breadboard. The wave flattens out quite a bit, but I used my laptop for a signal source and it does not go very loud, so all I could see was slightly wavy trace on the outputs. I was not able to tell, for sure, if the outputs were different, or not, but I do not expect them to be very different. I could not get a 4066 locally, so I am waiting on that to add the second stage.
  2. Circuit Help

    Yea, I plan to breadboard it first, only problem is I do not expect to see the LM3915s until the middle of next month. I have one more part to figure out, the clip indicator. Since it needs a reset button, to turn it off, if it goes on, it is not as straight forward as just turning it on. I tried making a truth table, but for 0 & 0 no change is made. clip reset result 0 0 0 1 0 1 0 1 1 1 0 It is trivial in software, the pseudo code would be for(;;;) { if(clip) LED = 1; if(reset) LED = 0; } Maybe I am over thinking it and a simple OR gate would do the trick?
  3. Circuit Help

    i have that one and the TI one, basically the same. The rectifier comes from there, as well as part of the switch. If I knew more about electronics, I could probably pick things out better. The guy at the electronics shop asked me why I do not pick simple projects to do. The only answer I could give is that would be too easy. While I generally need help, I learn ,more if I am in over my head. I think I have the hold part sort of figured out, although I do not think I have it right.
  4. Circuit Help

    OK, I think I have the switching mostly worked out. I need to redraw and organize this better, but I think the idea is sound. If I understood the description right, I should be able to take a branch from the rectified signal, pass it through a resistor and capacitor, in parallel, then in and out of the 4066, and finally tie it to the signal input on the LM3915. That does not sound right though, and I feel like I am missing something.
  5. Circuit Help

    Double post, not sure how that happened.
  6. Circuit Help

    Hmm, After going through 300 or so magazines, I found one project using a LM3914, but it was unhelpful. In my web searches, that landed in a forum where this question was asked, someone always says there is an example in the datasheet, but no matter how many times I look I cannot find it. Or that examples are readily available, but that is close to an example as I can find, which is why I tried asking for myself. A couple times a circuit similar to the one I mentioned was mentioned, but only as far as a parts list. I did finally find one, in the datasheet, that had a switch, so I have an idea of how to do that part now. I am still not clear on how to do the hold though. The chip really has not been obsolete for that long, I think it was still readily available at the beginning of last year. I have never had a problem buying from China, other than waiting a month to get my order. As long as they work, it is not taking away from anyone, since the original manufacturer stopped making them. At 10 for < $5.00 shipped, I will have plenty of extras, if I ever need them also.
  7. Circuit Help

    I will probably switch to using a micro, but getting something working, without one, should help me with writing the code. I record concerts, and recently switched from recording into a laptop to a multi channel recorder. While I have used worse, the deck's meter is lacking, compared to the software one I am used to. One reason for building this is to get more resolution, the only markings are at -18dB (?) and 0dB. Also, there is no peak hold, so unless I am looking at it, when a spike happens, I do not know how close it came to clipping. In addition, I also want to add a clip indicator, as I have found the one in the deck to be unreliable. I ran into this the other day, which got me thinking about this project. This would also give me better visibility. I looked at a couple chips, and the LM3915 seems to be the best fit for this project. For the most part, all the examples I have found are for "dancing lights" which might be nice to look at, but not of much use for my purposes. The base, "dancing lights", part is pretty straight forward. The peak hold and clip indicator are where I hit a snag. Doubling up the LM3915 and using one in dot mode, for the hold, seemed like a good idea at first, but not so good the more I think about it. I found one explanation of switching between bar and dot mode to achieve the hold, but without a schematic to reference it is hard for me to follow. Ideally, I would like the peaks to stay lit, as opposed to falling off, as is normal. Thinking about it more, an extended hold time would be a better option. That brings me to the last problem of the clip indicator. That is easy enough to light, but needs to stay lit, until reset. This is the meter I am used to, and what I am trying to somewhat emulate. The inner bars are the VU meter, but it is the outer, peak meter I want. The values to the right are what I was thinking about with making the peak hold persistent. While I will not be able to go get a beer and come back to see that I was coming close, and should probably turn down, I would like to be able to see how high it got after I hear a spike in volume, or crowd noise. A simple clip indicator will be good enough to warn me of problems. Now that I explained my goal good enough, I hope, on to what I have so far. The recorder runs on 12V DC, so I figure sharing a battery would be the best power solution. If this ends up too power hungry, I bring spares, so I can a separate one if I have to. I will need to come up with a way to drop the voltage, for the LEDs, but that can wait for now. The second LM3915 can be ignored, I just did not delete it yet. The rest is mostly taken from the datasheet, so should be OK, except deciding on values and what not. The 5V for the LEDs is just an arbitrary number to fit the requirements; 3V < > Vcc. What I need to figure out first is how to do the switching between bar and dot mode. The circuit theory, from the meter kit, linked above, uses a transistor, nand gates, op amps, and bilateral switches to do this. While I can sort of understand how each works on its own, I am lost when it comes to putting then together. If someone could help me with that part of the circuit, it does not have to be a direct fit, just something similar, it would be a great help.
  8. My Stupid Question Space

    Cool, it is certainly cheap enough, that I will probably go ahead and order one. Not sure when I will get to use it, but it never hurts to have test gear.
  9. My Stupid Question Space

    That is exactly what I was looking for. Switching all at once would be better, but cannot have everything. I started with the value line workshop, but did not care for all the C&P involved. The book seems to give better detail on why you are doing something, as you are doing it. Plus it allows me to work on a breadboard, and figure out how I need to write the code to make it work, as my first question shows. Unfortunately I have not had time to move onto the next step; adding a second LED and button. I have taken a little time to look into logic analyzers, and found this one on ebay, that should work with sigrok. I assume that is what you all are referring to.
  10. My Stupid Question Space

    I was hoping there was a setting, or something, I did not find. If I remember right, it was easy to switch back and forth in VS. I have a PDF that goes up to 0xff, on one page, so that is handier than using a calculator. I could probably whip up a converter to do the same easy enough also. I did that for converting to/from metric because I got tired of looking it up all the time. I hope to get past the LEDs eventually, but there is a lot more for me to learn, and I cannot just breeze through it all, like with Arduino. And before someone says look into Energia, I am not looking for the easy way out. I am hoping to eventually find employment.
  11. My Stupid Question Space

    Hi, I have not gotten to interrupts yet, just just the cheap and dirty way the book describes. I need to wrap my head around bitwise operations first. I also need to get used to CSS. I never looked at registers before, except for the little assembly programing I have done, so I did not think to do so originally. I did find them, and found out why I got lucky, all the pins were set at the start. That leads me to another question: is there a way to switch to binary from hex? It would save me having to look at a chart to see what actually changes. veryalive, I have an analog scope, I think that would work as a limited logic analyzer? At this point I have only turned an LED on/off with a button, so there is not much to see with either one.
  12. My Stupid Question Space

    Ahh, I kept missing that second part, and it makes sense. It is good to know that I just got lucky on my first try. Now I will not be scratching my head, next time when I would probably not be so lucky. Much thanks!
  13. My Stupid Question Space

    Since I am liable to have a lot of these, I figure it is best to just consolidate them all into one thread. I think I am fairly competent in C++, for desktop, but am new to embedded. My electronic knowledge is very basic, at best. Most of my questions will most likely concern the architectural, or electronic, elements of the msp430g2553 in general, since that is what I am working with, although they could be more general, or involve code, as I learn more. I am currently reading MSP430 Microcontroller Basics . If you are familiar with the book , you will know it involves a different chip and was probably written before the Launchpad came out(?). I am definitely not using the same board anyway. Instead of trying to use the on-board stuff, I am working with a breadboard, also. Everything else aside, this means that is not possible for me to just copy the code and see how it works. This brings me to stupid question #1. The second program involved using a button to turn the LED on/off. I figured out how to enable the internal pull up/pull down resistor, but did not find anything about how to set it to one or the other. Since what I did worked, is it safe to assume that the chip is smart enough to figure out witch one you want?
  14. CCS7 Requirements

    Oops. I kind of mixed several things into one there. I should have said; I only have a 32bit Linux VM, so I would have to install a 64bit one. It seems to be working, on Windows, for now, so I should be OK. Going back to CCS6 will be the next thing I try, if I run into problems I cannot find a work around for. I am not sure what to make of the advice/problems part of CCS. Since the code I copied is supposed to be what comes installed with LP, it seems odd that it would show 8 problems with the code. It is either extremely picky, or TI did not do a very good job with the example code. I suspect it is a little of both.
  15. CCS7 Requirements

    I only have a 32bit Linux VM, buy I think I will be alright for now. I C&P'd the blinky code from the workshop onto a blank chip and everything seems to be working. Now the fun part begins, learning how to actually write the code myself.
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