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Elven Commander

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  1. I had a flyer from a local company in TO that sold em, I'll take a look for it this week, I'm sure it is around somewhere
  2. Hi, I was wondering has anyone out there has used both the digital and analog scopes and function generators?? What do you prefer? I have been looking at getting a digital scope, as they are cheaper and the ability to save and print your findings seems neat. It also seems portable which could be very handy. I just don't want to make an investment of this calibre for something i've never used or known anyone to use them. Thanks EC
  3. Hi all, I was drawing a schematic, but am usure how to draw a USB connection for it, how is this normally done?
  4. Hi all, I'm starting to do some self research, and was wondering if anyone had any chips they have used for this type of thing in the past, that they might suggest to someone else. I am wanting to make a digital reciever and or transmitter. I have built a simple FM transmitter before, but it is very difficult to tune. So far I have found one, the TDA7021T FM radio circuit for MTS, but I haven't had a chance to read the datasheet, I'm going to print some of it off when I get access to a printer.
  5. Hi all, I've made alot of progress on my project. I have a working display unit of 3 7 segments, and am kinda working backwards. I have all the driver/decoders connected, and all those have a decade counter(sp?) connected to it. I am at the point where I am a bit unsure of how to proceed. I am using a thermistor. I know i must somehow compare the voltage to a base voltage and if it is below it is -'ve or above being +ve. I have read about a comparitor circuit I think it is called 2 capacitors in series across the 2 inputs, and then 2 resistors, the top resistor is the thermistor, and the bottom would be the standards room temp value ie 1.2k. Then the output is from the bottom of this which is ground, and from inbetween the 2 resistors which is the +'ve voltage. Am I right about this??? how do you know what kind of capacitors, do you just use the max voltage that goes into your circuit? and what kind of power would you use for this? My major question, is if this indeed works, how does it make the leap from a change in voltage to
  6. Hi all, I've been doing some thinking lately, and have a few more questions. I looked into the ICL7107 that was suggested and is used in the voltmeters on this site. What does "an internal voltage reference" mean? I found myself the 7107 datasheet, and still unsure about some stuff. I know how to connect up my display units etc. I will be using a thermister to find the temperature. I was looking at the Led display digital voltmeter in the projects section. According to this the input goes in threw the 1 and the 2. It passes threw 2 resisters and a capacitor. R4 on the diagram, I could just put my thermister here in place of R4. All I would have to do is hook up power to it and it would measure the voltage. This is my understanding, am I close to the mark? If I am correct, the one thing that was eluding me, how does it compare a voltage that it recieves and knows, that hey, that there is = to 30
  7. Hi all, I am making a digital temperature gauge and had a few questions. I am using a thermister to detect the change in temperature. I know that it sences change in temperature, but how do I make the circuit realize this? I'm not exactly sure how to go about this project. As of right now, I know I want to have 3 display panels (7 segment) show the temperature. I know how they are labeled and after some testing I have all of them working with the decimal point. I also know i need a driver/decoder chip for them to work. My display units are common cathode, so from what i've researched the 74LM48 is the driver i'm looking at. I have the datasheet for it, and know where to send my a-g to etc. What I wasn't sure about, is I have 3 display panels, does this mean I need 3 of the 74LM48's? Something tells me that would be terribly inefficient, but how would more then one number be presented at once on 3 seperate displays if you only used one driver?? Does anyone have any suggestions or direction of where to go between my thermister and the driver/decoder?? Thank you, EC
  8. Hi all, I was having some troubles brainstorming, and thought I'd give posting here a try. I am looking to make a digital project, that I will interface with my computer and control a stepper motor to proform a task. I do believe I will have to use gears, since from what i've read the stepper isn't all that powerful. I was just curious what kind of projects people may have seen or built out there?? How difficult were they?? and if you built it what interface type did you use with your computer?? I've thought of a chair that can move up and down for your back, controlled from the computer, or a blind closer, not exactly sure what all can be done with it, and the limitations etc. EC
  9. Hi all, I have been pondering this idea for a little now, and decieded to come and check out this site. When I got here, i saw that there was a related thread started and I have read that thread and searched around a bit. My aim is to make a project, and I would like to play mp3's that are playing on my computer, and play them in the other room. My first question is, I read in the other thread that there are kits that do this, by using a PCI card. If I so wished it, is it possible to design and make my own PCI card for this ??? the other type I've heard/read about is where you plug it into the standard headphone jack. What is better??? I must make a digital project and thats all the specifications I have, right now i'm just idea surfing, and the idea of making my own board has always seemed cool. If I did make my own PCI board, how hard is it to get the data thats being played on my computer to there?? I have made a FM transmitter in the past, a variable transmitter. Is there a range that a devise like this would normally follow. I was thinking mybe 88-90 mhz or something like that, but I wasn't sure if there was a prefered, or generally used range to go for. I'm not completely sure, but I was thinking that FM would be better then AM for a project like this. I know I wouldn't want a variable FM transmitter for the full FM spectrum (or so i think) would a device such as this have an option like a switch or what not, position 1 88.1 postion 2 88.5 position 3 88.9 etc?? If I were to make a project such as this, Basically you would take your signal from the computer, turn it into RF and then transmit it, and play it on the external recieving devise. From my understanding thats what I would have to do. Would i have to run it through an amp first? Thank you for any input, i'm fairly new to electronics, and any help, comments or suggestions would be greatly appreciated. Thank you for your time, Elven Commander p.s. I almost forgot, the BH1417F, Wireless Audio Link IC, I understand that this chip sends the data as a RF using FM, but I wasn't quite sure as to what "generating stereo composite signals" meant which is the 2nd function of this chip.
  10. Hi, I am making a project dealing with DTMF and taking a number that was inputed and using that number to do something. I am pretty new to this and have been doing an immense amount of research and came across a few questions. 1. I need to connect to the phone somehow to pick it up when I call in, and then to get the inputed numbers to my DTMF chip. So I was thinking hey, that is what answering machines do, I could probably just hook into one of those, where I can set the amount of rings it can do etc. etc. Does anyone see a problem with this? My major question was if anyone knew generally where to attach my addition into to get the input signal, web, expereince or whatnot, I was researching today, and was comming up empty handed. 2. I am using the MC145436 chip for DTMF, I have never created anything from scratch, and this is my first attempt. I was reading the data sheet, and understand most of it. I am unsure of the DV pin, and then the GT and Xen pins which appeared to me to be directly related. The GT is for Guard Time, Xen for an extermal oscillator I do believe (not in front of me at the moment) My other question with this is this: Some pins require a logic 1 (in my case the ENB) that means I just need to send my +5V from VDD into ENB aswell right?? or am i very far off track? Thank you very much for your time Jason
  11. thank you for your reply, actually that is quite helpful, and will give me somthing to work on in the morning, thanks EC
  12. Hi all, I am a highschool student and for electronics class I had to come up with an idea and build it. I want to make something, that picks up like an answering machine after so many rings, then you can input 4 digit number and it will then allow you to enter additional numbers to do things etc. The four digit number is kinda like a pin number. I know that I need to do DTMF for it, and that each number is composed of a high frq and low frq. I have been trying to study chips but i'm new to this stuff. How do I know what chip I want to use, and once I deciede how to i connect that to everything else? I am currently looking at: Mitel MT8888C, MT8870D Silicon Systems SSI203 DIP-18, SSI204 DIP-14 Motorola, MC145436, and UMC 9203 DIP-18, UM9204 DIP -14, 92870A/B/C I'm think all of these are pretty good chips for me to be using in this project, but as i said i'm new and am not really sure. I think i might be leaning towards the Mitel dedicated DTMF MT8840. Has anyone ever done this?? or has anyone also researched this and help me find a good place to start. One of my main things, is if I choose the MT8840, is how to go about puting that in my own circuit, I know i'll need power to it, ground, among other things, but I'm not sure how to take the data from the phone and put it into the chip, and how to get my output. Thank you, EC
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