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  1. From: ELM This is a practical white LED head mount lamp (flashlight). Recently many white LED flashlights appear on the market. However, most flashlights require three cells because they are regurating output current with only series resister. The odd number of cells except one is not good, and a margin between VLED and VBAT is too small, intensity of light is affected by variation of input voltage within the battery life. Thus I built a white LED head lamp which operates with two cells and controls output current.
  2. From: ELM This is a video scan converter to display NTSC video signal into VGA monitor. Normally, the VGA monitor occupies most desk top space, so that everybody will be thinking that if the VGA monitor can be used for video monitor. I tried to build a scan converter. Right photo shows my VGA monitor which displays TV. The VGA monitor (Nanao T560iJ) has two VGA inputs, BNCs and a D-sub, it can easy to change its inputs without any external video swicher. A small monitor at left end of the photo is a sub-monitor to be used during the VGA monitor is used for PC. Now, difference between NTSC and VGA is shown in table 1. The horizontal refresh rate for VGA is just two times faster than NTSC, and vertical refresh rates are equal. Thus, only converting the horizontal refresh rate is sufficient for NTSC to VGA scan converter and its circuit diagram is very simple. If there is difference between vertical refresh rates such as PAL to VGA converter, it will require frame buffer, the circuit diagram will become complexity.
  3. From: ELM A video test pattern generator will be needed when calibrate or test video equipments. To characterize system performance and understnad it quantitative, wave form monitor, vector monitor and related video measurment equipments will be required. Some generic patterns, shch as color bars, cross hatch, dots and full field, are also used for home video creation to calibrate video monitors without any measurment equipment. This kind of test signal generators for personal use are often found as construction kits, however, most of the kits are designed on cheap analog method and the wave form is not accurate, therefore it cannot be used as a standard signal in fact. I designed and built a digital video test signal generator in order to generate accurate reference signals which can be used for calibration and measurment of video montors and home built video equipments. Amazing.
  4. Hello audioguru and MP. First of all, Thank you for providing me some light in this issue. Strange, the Protel library was wrong about this device, checking the IC, now, it has pin8 GND >:( It's a demo version by the way... I've check the first circuit (again) and changed the IC's, it won't work if not disconnect the 8 pin. What i remember, I've mis-wired the first board and the IC start to heat very fast (I burned my finger after that...). What i can think is that something inside this chips are burned out (my fault), that's why my friend and me could not build an second unit of this. The sound with new IC's are different, because i've burned out the pin 8 ;D Thank you audioguru and MP!
  5. audioguru I Love you ;D (you know what a mean, when i say love, not the LOVE you fell about other person, well...never mind) It works!! ;D ;D ;D ;D It works!! ;D ;D ;D ;D All the five circuits, put the regulator back and disconnected the pin 8 from ground and is great, working!! I've check the first circuit also, with or without the pin 8 grounded it will work the same way. Did you build the circuit? And one thing that i can't understand is why should i disconnect the pin 8 to make it work? Thank you very much audioguru and MP!!!! ;D
  6. Hello MP, Well, i'm not trying to redesign the circuit but to build another since none of my friends could, what i think that was strange at first but doing again at my home i could not do it also. I'm sure all conections are fine and checked step by step. I've checked the components, changed the IC's 5 times , they are from the same serie, same type (LM386-N1) and from same store, not only the IC but the components. Rebuild the board also 5 times using the working one and schematic as base, checking every inch but the results are the same, it will only work if I remove the regulator, and if I do that, hum increases and oscillations occur, like a police siren if i plug the headphones with the circuit on. Yes, the input sorce was the same on both units also the output headphone. Thanks!
  7. Boy this is giving me too much headache ??? The above circuit was the one i've build as a headphone amp, I do have a working one, but the problem is that i can't build the second (also my friends). The problem is that when i turn the power on, the sound start to crack(or something like that), i can hear only some cliks and pops very distorted. Burning my brains out for a few days i have discovered that if i remove the 7806 regulator and bypass the voltage from the bridge the circuit works (with alot hum noise, but works fine). Also, when i turn this on without the 7806 regulator, i get a huge pop in the headphone (almost got def because of that). What i can't understand is that i have a working circuit with the same parts. With the regulator i have a 5.5 DC output, so i change the 7806 to 7809 and T1 to 12V 500ma (+-15V output) that resulted in 8.9 DC output, but the still the same problem, remove the regulator and all works again >:( I do have a kit from SONY, an video composite to RGB converter based in the old V7021 IC from SONY that has a LM386 for audio output and uses a 7805 voltage regulator to feed all circuit and works fine. ??? Searching around i have found this Supplying power to opamps isn't as simple as you could think. It isn't enough to connect a 9V battery to the V+ and V- pins on the opamp, but an opamp needs to be connected to a bipolar power supply or it needs to be biased to half of the input voltage. So this is what i miss?? Do I need do feed a -9V in to the pin 2??? Or "biasing" the voltage will do the same effect?? And Why the first circuit works and this second not?? Thanks in advance! Wellington
  8. Rectifier Applications Handbook In PDF
  9. Yep, i will get me one soon ;D The problem to make the computer respond to any one is that some stange can get in to your computer and stole data etc.
  10. Hello velosity1, I've been thinking about this computer structure for years, let me try to explain my version. All started with Knight Rider here in Brazil is know as "Super Máquina (Super Machine)" when i was eight years old. Voice recognition - Identify the main key of human voice that we humans can separete one person from another, like a voice signature, that is unique. There are some software of voice recognition over the internet but they still lack in this feature, in noisy ambient the computer can't identify the registered voice. Command interpreter - After identify the root commander (me or you) accept basics commands, like this example: Computer (check to see if is from root, if it is respond if not keep silent) Turn on TV at Channel 5. Computer - Call command from root. Turn on - (Command) turn on something TV - Check if there is any device connected in the central named TV, if no TV is registered, return error, if found wait next command. Channel 5 - Registered command for TV to select channel or the channel frequency. So the computer will wait for specifics commands, more like: Turn on, TV, Channel 5. Or like to give another person user permission to use the system. (!) = wait next command Me Computer (!) Register (your name) as regular user. Computer responds (!) User (your name) registered, wellcome (your name)! Or Computer (!) Register (your name) as root. Problems: 1- Create a program that can identify you. 2- Integrate all your electronics (TV, sound, lights etc) with the computer. 3- How the computer(program) will learn new commands, can be done if the program was made to accept new commands and if this new command could link to ones registered. 4- Make the computer respond with pre-recorded or text recognition. 5- Build a huge hardware to integrate all this. This could be created with C in any linux computer, but to make this happens you will have to be: An Software/Hardware Engineer Iám also good with ideas if I could found a company that accept this kind of stuff i would make this worl upside down. ;)
  11. Hello audioguru, At last it work well ;D Yep, please note that the original uses normal cables to input/output this will increases the interference, i did mine with shielded cables at the input and output. The bass of this little 'beast' gives a good punch without killing the high frequencies, thanks to R/C in at pins 1 and 5. This is that kind of project to put in the "must have" section.
  12. Hello all, The other circuit that i've build was simple, but the sound was too flat, so i've build this one, the original can be found here, what can I say? Very, very, very............good sound, so clean plus a good bass kicking (much better than the other one), i've made some modifications to fill my needs and to work with the enviroment that i was using it. The original circuit distorts the sound a bit (from the xbox AUDIO OUT used as source) and the volume at full distorts alot more. I've include regulated/well filtered power supply circuit to use with it.
  13. Thank you audioguru for the tips. The board of this circuit is very small and can't handle a 1000uF cap, also the box that i have put this boards is small too. With that changes i have a clear (flat) and soft sound, to make the circuit punch the bass a little, using this diagram i use R/C (R7, C6) in parallel with the 180k resistor it will give a good bass, but also kill a good range of the high frequency and drop the final output to half. To fix that, i change the values of R/C, R is 220R and C is 100uF, still give a good bass and some midle range frequency and still cut the output in half, so I reduce the 180K resistor value to something like 68k. Now this solve some of the flat sound, but when build this circuit i did not know this site, what is very good, so i will drop this and make the one in the link above. By the way, i did not know about Toshiba selling secrets, a japanese company doing such a thing is very rare.
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