Jump to content
Electronics-Lab.com Community


  • Posts

  • Joined

  • Last visited


Everything posted by Theatronics

  1. The circuit produces a series of flashes in the IR range. Most TV remotes blink an led on and off at 38-40 thousand flashes per second. This high speed flashing is then switched on and off (Modulated) to send the actual data. The problem may be that the detector on your devices is very sensitive and is able to pick out the data even though you are sending a different IR signal. Think of it like radio. If the transmitter and receiver are both tuned, outside signals will have very little influence over them. The only way to JAM a signal is to overpower it so that the receiver can not detect the original signal, or to match the signal carrier and send a interfering series of pulses. I'd suggest you try a 556 chip, it has 2 555's in it. Set one up to create a 39khz signal and set the other one up to produce a 1khz signal. Use the output of the 1khz signal to (Modulate) the 39khz signal. Imagine you are in a loud stadium during an exciting game. If your friend beside you tries to talk while the crowd is yelling loudly you may not be able to hear him at all. This is the method of simply overpowering the receiver with blanket noise. Later during a quiet moment you have 2 friends who both try to say something at the same time. You can’t understand them because their voices blend and make no sense. This is similar to what I am explaining. What your current circuit is doing is similar to you and your friend talking while a trumpet player holds a very long steady note. The note is easy to ignore because it sounds nothing like your friends voice and it is not loud enough to overpower his voice. In fact a single note would have to be a very powerful signal to interfere because the modulation helps the receiver pick out the most subtle signals from a sea of IR noise. Some equipment will even work in direct sunlight, now THAT is a noisy IR source. I am sure someone will post the Circuit Diagram. -Mike
  2. type: CD\ that will take you back to the prompt. (Root directory) -Mike
  3. Hey, We could combine those ideas! Use a spinning motion to store energy in a weighted bat And then hit the ball with the bat at the end of the swing. Still one motion. Use a notched tube to hold the ball. The Notch on the back will guide the bat to the exact point on the Ball with every hit. By tilting the tube you can get different Trajectories. -Mike
  4. The >Most< basic High Voltage fly back was from a book Called “How to build your own laser and other space age devices” (Or something like that) It was a very interesting collection of high voltage and fringe electronics Circuits that are fun to play around with. The concept is simple. Two transistors push and pull a transformer winding. A secondary winding creates a small voltage that is then used to feed back Into the base of the transistors in order to create an oscillation. I think this is a “Hartley” type oscillator. There is considerable power loss in the design and it is a bit of a run-away circuit seeing as it is just a high gain amp with a serious feedback problem. The “Pro” version of this circuit is actually more elegant. It is a lower power device and only drives the transformer at
  5. I was unclear, My bad. They are not designed for wide ranges (10uf -100uf) like variable resistors. A closer analogy is a guitar string. They are designed to make a particular note, however it is up to the installer to tune it once it has been installed. Caps that little (pF range) can be severely altered by the width of a trace or the Length of a resistor. If you NEED a very exact value, sometimes you need to install A part with a little ‘wiggle’ room in the value. The range is not very big. They are listed By the TARGET value. With some flex on either side.
  6. Remember that a tennis ball in normal use is meant to absorb energy and then return that energy to reverse direction. You do not need a LONG throw to project the ball. A slug from a solenoid moving very quickly will make impact with the ball and compress it. The compression would be the same as if you had thrown the ball on the floor. After motion stops the fall is flattened out. The amount of flattening depends on the energy imparted. Then the ball returns the energy as it pops back into shape and springs from the floor. Force is speed times mass. If you weigh the ball and find a plunger that weighs more then the high speed movement of the solenoid will cause the ball to pop from the tube. 80cm should be easy to reach with this type setup, and it will not require a long tube or a complex compressed air system. You might want to put a large bank of caps onboard and then use a high current relay (Like an automotive starter) to dump the energy into the coil. This will give you much more kick in the coil. -Mike
  7. They are adjustable Caps. They have a very limited adjustment range. When used in a tuned circuit (radios) They can sligtly alter the frequceny of a tank. Sometimes used in production to adjust for cheap parts by tuning systems up before they leave the factory. Other times they can be use as part of a tuning mech such as a dial on a radio (But that isn't actually the same thing; just a close relitive.) -Mike
  8. Well, I knew there was flying involved, and I knew it was the High voltage from the screen, My first definition was "What happens when you touch it; You fly back" At least I was close. Some day I will need to test the depth of the ocean of Audio Gurus knowledge. -Mike
  9. A fly back is just a transformer. The name ‘Flyback’ comes from television raster scan terminology. The ‘Fly Back’ is the moment when the electron beam “Flys” from the lower Right corner of the screen “Back” to the upper right corner to begin drawing The next new frame. The actual purpose of the transformer is to generate the high voltage needed To keep the CRT working, but the AC signal fed to the transformer is the same As the ‘Flyback’ signal. Thus the transformer was named. There are also other windings on the low voltage side of the coil. These are used To provide low voltages and negative voltages for much of the circuitry. The coil was wound to respond to the ideal frequency of the TV frame rate. In the NTSC system (M format) is just under 30 frames per second. (30Hz) If the Transformer came from a PAL tv set use 25hz. (25 frames a second) The input voltage (current limited by impedance) can be anything but the Transformer will break down if the windings over heat or the output voltage Punches through the insulation around it. I’d start with a 12V 30Hz Push Pull Circuit. If you can find an OLD TV set you might find an exposed core. Usually the look like A disk with a square through the middle of it and then a small winding on the other side of the square. These are great for experiments because you can completely remove all the primary windings and make your own. Winding your own coil is not hard to do. In fact some people prefer it. (Like the one I am leaning on in my picture) if you are serious about a large coil stay away from PVC And any metal. Find a cardboard tube (Sono brand concrete tubes offer a good range) Also you can try the cardboard tubes in the middle of carpet rolls. Check with a local store. (Hint: Dumpster!) Use a resin or polyurethane to protect and harden the form, then wrap away. On these larger coils you usually only wrap 1 layer thick. Also Tesla used a trick To get nice even wraps on his coils and still keep the wire spaced far enough apart to reduce internal capacitance and arcing. Wrap a string or thread along side each wire. When you are done wrapping, remove the string and coat the entire thing in a coat of Varnish, polyurethane, or resin of some sort. Coils can be any shape of size and there are lots of formulas to tune them to the exact frequency you want. Most beginners just make a large secondary (about 100-200 turns) And a Low-Z primary (out of copper pipe on a wooden form – maybe 5-10 turns) Discharging a large capacitor through the primary will produce a large single spark. The challenge then becomes to tune it and find a way to provide LOTS of discharges quickly. -Mike
  10. When you “PLUG” a chip into a programmer several things happen depending on the type of chip. Good old Eproms have a glass window (Usually round) that you can see through. That little square inside IS the actual ‘Chip’. The reason for the window is not for vanity or decoration. Actually it is there to allow UV light to strike the silicon. UV light hitting the silicon causes all the electrons in thousands of tiny junctions to change to an ON state. If you read a freshly ‘erased’ eprom every bit will be a ‘1’. “Programming” an eprom is the process of clearing some of the ‘1’s and making them ‘0’s. This happens usually because of a high voltage, sometimes as high as 24 volts. An address is applied to the address pins (10110101 00110001 for example) And the data is applied to the Data buss (1110 0010 lets say). Then with the Vpp (Programming voltage) applied to one of the pins, usually set aside for this purpose, the ‘WRITE’ pin is asserted and any data line that has a ‘0’ on it will open up a bit in the chip at the address given. Think of it as ‘Blowing the fuse’ When you read back that address later all the ‘BLOWN’ fuses will read zeros and the intact fuses will read ‘1’. The true magic is that the UV light “Heals” the junctions so that you ca clear out the array and start again. Writing to an EPROM takes a bright UV light source. You can clear them by leaving the window exposed and setting them in the sun but the best way is to use the proper UV lamp. The programmer not only needs to provide certain voltages but for each chip there can be different pin outs. Also different manufacturers and styles of chips require their own timing. Too fast (And sometimes too slow) will cause programming problems) The final problem is that the chips are slow to write. Even if you built a PCB with a built in UV LED and power supply to enable programming on board, the WRITE speed is amazingly slow. That’s where EEPROMS come in. Notice the extra “e” ? it stands for Electrically Erasable Programmable Read Only Memory. These chips do not need a UV lamp. BY applying the proper programming power these chips can ‘write over’ the existing data without having to clear the whole chip first. Some EEPROMS can even run on the standard 5 volt power supply. The only drawbacks to the EEPROM are a lack of write speed, and the limited write cycles. You can usually only write to an EEPROM about 10,000 to 1million times before they start to wear out. Also the write speed is only slightly faster than the old EPROMS. The limit to the number of write cycles and speed has made RAM a critical element. Random Access Memory is very fast and it allows you to read and write very rapidly. The down side is that when you loose power the memory goes away also. There were ‘Bubble memories’ and ‘Static’ memories that tried to get around this by using a tiny amount of power to maintain their data when the main power was shut off but they never lived up to the speed of ram and the longevity of rom. The newest version is called FLASH memory. A similar technology by RAMTRON called FRAM memory works about the same. These are very fast RAM style chips that can maintain their data for 10 or more years without any power. They have a limited write cycle but it is in the ‘billions’ of cycles range and they can run on a single power supply. There are 2 other classes of chips that are “Programmed” they are PGAs and Microcontrollers. PGAs are (Programmable Gate Arrays) These are chips that have a series of logic gates in them connected to a memory array. Using special software you can design a complex logic gate that would need dozens of discrete parts to assemble, on one small part. The software then creates a series of on/off signals to program into the memory much like data is stored in a Eprom. The difference is that you can’t read and write the memory in these devices. Instead the memory is used to set up the logic gates and ‘program’ the chip. Microcontrollers are actually very small computers on a chip. They have a processor, a ROM to store programs and a RAM for working data. The program that the computer runs is stored in the ROM. Similar to the PGA, special software translates the program that is written into a series of binary data. Once the program is compiled it is written to the EPROM on the microcontroller. Again this data is usually not directly accessible under normal use. The EPROM data on the microcontroller just holds the actual program for the chip. -Mike
  11. I have heard of such a thing but only as part of a camera package. Flipping and turning a video image is a complex trick. I am not aware of any Digial processor chips that make this any easier. Usually it involves a image capture system that converts the incomming signal to a array of digital data. Then a second circuit scans the memory and creates a new video signal based on the data in the array. For instance the pattern below. A B C D E F G H I J K L M N O P would appear in a video signal like this <Flyback signal><Retrace> A B C D<Retrace> E F G H <Retrace> I J K L <Retrace> M N O P Once captured in an array the data could be scanned from Bottom to top resulting in this pattern <Flyback><Retrace> M I E A <Retrace> N J F B <Retrace> O K G C <Retrace> P L H D Once re-assembled on a screen the image would appear turned 90 degrees to the right: M I E A N J F B O K G C P L H D Scanning from bottom to top starting at the right and moving left would result in a 90 degree turn to the left. Scanning from right to left and bottom to top will result in a 180 turn. -Mike
  12. The circuit is in series. If you flip one switch you will get the resistance of all the resistors between points A and B. Just imagine the lines (Wires) as pipes. With only one valve closed at at time the 'water' must flow from A to B through a series of resistors. The photo-resistor you had in your original circuit can be replaced with the circuit I provided. I am not sure what the range of the device you were using is so I will guess that it is a 10,000 ohm resistor when dark and a 1,000 ohm resistor in bright light. To approximate the same range you could use ten 1,000 ohm (Brown - Black - Red) resistors. By closing only 1 switch the circuit will see 1,000 ohms (Or 1k). As you close successive switches the resistance can be changed all the way up to 10k. Unfortunately this design only allows 1 resistor to be connected at a time. Pressing two switches will effectively SHORT out a resistor thus removing it from the stack. In musical terms your instrument is monophonic, or single-voiced. Flutes, Tubas, and the human voice are all monophonic. If you want to close two or more switches and get polyphonic (Multi-voiced) sound such as in guitars, Harps, and pianos, you will need more oscillators. You could try etching a series of circuit boards that all have a micro switch on them. Each one would be equipped with a circuit similar to yours and a variable resistor. By tuning each circuit to a musical tone you could mount all the boards together and create a keyboard. Many of the early electronic instruments used this method. I have included a simple drawing of 3 resistors in series and parallel. The same values are used in both drawings. -Mike
  13. Resistors can only combine 2 ways. Series or parallel. In series it's easy, Add up the values and you are done. In parallel it's a bit tricky.
  14. Black tape in a I.C.E? Sticky.. I would like the question about (Why) answered. Maybe the IR or Heat isn't the real issue. Is there some 'sub-visual' bias gong on here? What little I know about 'glow plug' engines tells me that removing the coil would cause the engine to stop working. So I guess that it it should be there, maybe it 'should' be glowing ? -Mike
  15. see, that’s the problem with using a CAD program to 'Sketch' something. I should have just drawn out the thing by hand and left it more ambiguous. I am not sure. I did say that the values needed to be 'fiddled' with. I built a setup like that once but it was a while ago. the 10Kohm should show +5v when the transistor is in cutoff. When the NPN goes into sat the current through the 10K will be determined by (beta) times Ib. If the 2.2k is seeing 5v then calc would be (Roughly) (5v - .7 = 4.3v) (4.3v / 2.2k = 1.95ma) (Given a beta of 120: 1.95ma * 120 = 234ma) So the current through the 10k should be 234ma ? well, the Vcc is 5v and 234ma * 10K = 2340v. Because that is not possible the Transistor must be in saturation. As a result the entire Vcc must appear across the 10K. As a result the Vbe at the second NPN would see near 0 Volts. Even if it saw above .7 volts due to junction voltages within the first transistor, that should not be enough to cause the second transistor to go into saturation and pull the output low. If the first transistor is in sat. and there is a bias on the base of the second stage of lets say 0.7V. That 0.7v wouldn’t overcome the Vbe knee and therefore the second transistor should stay in shutoff. If there were a Bias on the base then a simple voltage divider (A second 2.2k to ground) would cut the bias in half and put us back in control. When the first transistor goes back into shutoff, the entire 5V is expressed on the base of the second transistor, through 12.2k ohms of course. 12.2K ohms @ 5v yields 0.41ma. 0.41ma * 120 = 49ma. 49ma though the second 10K resistor is 491 volts. Again the transistor is in sat so the whole voltage applied appears across the second 10K and the Collector appears to be at 0V. (Or darn close) Unless I am overlooking something, I think I got it right. Or at least close enough. It was just an example of the concept. If it were me I'd use a driver chip to shape the signal, A quad Op-amp would work. But because he had already mentioned a transistor style set up I went with that as an example. -Mike
  16. Not to be blunt, but - no. The -1.2 V is the answer. It regualtion comes from the LM317. if you feed it the negitive ref voltage, you will get 0 volts out. I have heard of Boostraping OpAmps with high power transistors to make high power amps and also using Ziners and high power amps to create power supples. Can it be done? I don't see any reason why not. But how would you very the voltage output of the device with a zener as the source voltage? I think AG's solution is the occoms razor in this case. -Mike
  17. The part is basicly a LOGIC level MosFet. You can treat it like a on/off switch.
  18. First let me say that the Texas Instruments datasheet is wrong.... Op-Amps are not for everyone. My brother in-law for example. Secondly let me say... Wellll.ExcuuuuuuuUUUuuuuse me. Forgot my Inverting vs. Non-inverting rules for a sec there. (shesh so picky.) Heres my best (and feeble) attempt at a NON-Inverting, HI-Z input Version of the same circuit.. Go ahead , rip it up. I know you are dying to.. I'll take my hurt little feelings over here and calculate some Hfe gains until I feel better. -Mike
  19. Yes, Guitar Pickups are very Hi-Z devices. But the input Z of an OpAmp with feedback should approach 10meg Ohms or more. Even without the feedback loop a standard 741 has a 2meg input on it. My gut is telling me the chip may have been damaged. I have seen a lot of 741s go south quietly. Some had some strange failures where they seemed to work but only partly. -Mike
  20. Your circuit is set up as a inverting Op-Amp with Clipping. The first part of the circuit is the two 100k resistors, They form a Virtual Ground for the OpAmp. The 741 is designed to run on a dual supply. By Cutting the 9v in half, the 4.5v that appears at pin 3 Appears to be the ground for the amp. I am not sure what the purpose of the 100uF cap on The low side of the divider is. It may have been intended To filter out noise and keep the ground steady. In truth, As the current is drawn from the battery the source voltage will Drop and the 4.5v will drop also. If the battery gets low, sudden Current drains could cause the Virtual ground to fall BELOW The stored voltage of the 100uf Cap. As the input resistance Of the 741 is nearly 20M, it is likely the entire circuit could Shift sound as the battery goes dead. I’d drop that part for now. The next part of the circuit is the feedback loop. Without the diodes the feedback is (1M / 1K) or X1000 The 1N4001 diodes then short out that formula at any Voltage above 1 volt. (Under 1 volt the diodes tend to Act like resistors – Look up ‘Knee Voltage’) That means that any input signal will be allowed to see normal Amplification unless the output exceeds 1V Pos or Neg. The remaining capacitors are just DC blocking. They let the Audio Signal through while blocking any stray DC between the guitar, The effect and the Amp. My first test would be to check for 4.5V at pin 3. (Assuming you have 9V at the battery) Pin 3 should be
  21. Fuzz is just a VERY BAD amp. The classic sound is the Jimmy Hendrix sound. I attached the circuit that makes that sound when driven by the right pickups. I am not sure what pickups he used. I am guessing they were just stratocaster single coil pickups. Humbuckers came along later. If you are getting clean sound or a very weak effect your pickups might be too weak. If you can't afford new pickups try heavy strings for slightly more output. You can also add a pre-amp on the front of the FUZZ circuit (A fet input Op_amp would be enough) can you send the circuit you were using along with what it was doing. Maybe you already have one built and just have a component in wrong. -Mike
  22. An entire schematic with parts would fill several pages. The basics of a UPS are just a two units. - a charger to keep the batteries topped off. - a Inverter to change the power from DC to AC. The charger isn't to complex. The Inverter is the tricky part. All an inverter does is create a sine wave (usually 50/60hz) then feed that sine wave into a very high power amplifier. If you want 120V AC at 60Hz then build a push/pull (Half bridge) amplifier that can supply the needed current (or wattage) The trick is to drive the amp with only the battery power. A hint, Most UPS systems use 48V batteries (Four 12V's in series) If you swing that through a transformer forward then negative you can get 48Vpp or 73Vac. If your transformer can handle bumping that up 3:5 ratio then you have 120V. If this still sounds like something you REALLY want to try then you will need to define a few basics first. How much power do you need. How long does the UPS need to run, Is the UPS a pass-though or a fail over design, Will you be driving resistive or inductive loads, and why would you want to build a UPS in the first place? Answer these and I'll help some more. -Mike
  23. What is your goal? Are you trying to turn a car into a generator? and why can't you use the battery? If you must do it that way you should get a REAL generator dynamo. (Don't try to spin a DC MOTOR) A real dynamo generator has wire coiled on the outside and the magnets spin on the inside. They can't create as much power as a energized field unit but they are easy to use and can be spun by anything from a old 2 stroke engine to a windmill. But seriously, What are you trying to do ? -Mike
  • Create New...