mixos Posted May 2, 2004 Report Share Posted May 2, 2004 This redrawn simplfied circiut from my collection was drawn ina special way by circiut maker and retraced in black to highlight it enougth to come out when photographed, for posting, ill post another similiar one soon and because it uses more of the 4017 decade counter pins, it allso makes a good decade counter testor.by Steven (received via e-mail) Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 2, 2004 Report Share Posted May 2, 2004 Mixos,Steven's circuit is not a knightrider, it is a chaser that misses a few steps. We have discussed knightriders and chasers recently in this site at: Electronic Projects Design/Ideas, "LED Flasher (very interesting)".In Steven's circuit, R5, the LED current limiting resistor, is not needed because the 4017 outputs have built-in current limiting at about 9mA with an 8.3V supply. In Steven's circuit, the transistors in the multivibrator have their base-emitter junction driven beyond their 7V maximum rating which causes damage to them.A good knightrider project is in our site's project section here:http://www.electronics-lab.com/projects/motor_light/035/index.html Quote Link to comment Share on other sites More sharing options...
MP Posted May 3, 2004 Report Share Posted May 3, 2004 steven, since you have already built this circuit, could you please reply to the questions asked?MP Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 3, 2004 Report Share Posted May 3, 2004 In order to avoid continuing confusion about knightrider/chaser, for those who have not seen the American TV show, is it possible to include the animated GIF:into the project article, above?Is it also possible to remove the phrase,"Knightrider" from the Projects Index for the chaser circuit:http://www.electronics-lab.com/projects/motor_light/028/index.html Quote Link to comment Share on other sites More sharing options...
steven Posted May 3, 2004 Report Share Posted May 3, 2004 :) with so many circiuts in my collection i havent got to biuld this night rider scanner as it was a talking electronics circiut from my colection but i now favour the one in this site, from steven Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 3, 2004 Report Share Posted May 3, 2004 MP,Thanks for fixing the Projects Index.Isn't it possible to include the animated GIF into the "Knightrider LEDs for Model Cars" project? I have a solution for anyone who complains that the GIF shows 10 LEDs but the project has only 6. Quote Link to comment Share on other sites More sharing options...
steven Posted May 4, 2004 Report Share Posted May 4, 2004 :) from steven, oh ill see if i still have the talking electronics mag and email the pic of the night rider scanner by talking electronics, yes it is a kit for the car. did i make any boo boo :o Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 6, 2004 Report Share Posted May 6, 2004 Heres a schematic of my up-down sequencial LED flasher that can sequence 16 LEDs, not sure how many LEDs were used in the original knightrider car .http://onfinite.three10.com/libraries/display.php?lid=8114&d=c524448053f994bcb48126b1b3904945 Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 6, 2004 Report Share Posted May 6, 2004 Nettron,Nice circuit. But 5 chips (the 5th is a 5V regulator) just to flash leds?The original knightrider car probably used light-bulbs. I would guess 8 to 10 of them. Quote Link to comment Share on other sites More sharing options...
MP Posted May 6, 2004 Report Share Posted May 6, 2004 Nettron, thanks for sharing. ;)Do you have a picture of the prototype? I think others would be intrerested to see it as well if you do.MP Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 6, 2004 Report Share Posted May 6, 2004 But 5 chips (the 5th is a 5V regulator) just to flash leds? Audioguru, you have a point there, i was thinking the same thing when i was first designing the thing. Wish the 74154 had had some type of F-F and up/dn counter built-in. I had thought about using a 4017 but it would only give me sequencing in one direction with 10 LEDs. Do you know of a stand alone IC that can do dual sequencing of 16 LEDs or more ?Do you have a picture of the prototype? Sorry MP, no i dont. I gave the board to my bro, seams he used it in a holloween costume for light effects. But I have the ExpressPC board layout on a floppy somewhere, i'll post it here if and when i find it. Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 7, 2004 Report Share Posted May 7, 2004 Nettron,We have a 6-LED knightrider circuit in our projects section. The 4017 counts forward lighting LEDs 0-5, and diode gates are used to light those LEDs in reverse order while the 4017 continues its count of 6-9. From a 9V battery, the 4017's outputs are current-limited to about 11mA, so a current-limiting resistor is not needed. The project is here:http://www.electronics-lab.com/projects/motor_light/035/index.htmlAn LM3914 dot/bar-graph chip lights 10 LEDs sequentially in both directions when fed with a dual-opamp triangle-wave generator. The LM3914 can be cascaded to allow umpteen-dozen LEDs, but the set-up adjustment will be tricky after maybe 50 LEDs.A D-A converter would feed cascaded LM3914s beautifully. Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 7, 2004 Report Share Posted May 7, 2004 We have a 6-LED knightrider circuit in our projects section. Yes i was looking at that earlier, nice little compact design. Its also available from Doctronics in kit form here:http://www.doctronics.co.uk/kits.htm#chaserUnfortunately wasnt enough LEDs for my app.An LM3914 dot/bar-graph chip lights 10 LEDs sequentially in both directions when fed with a dual-opamp triangle-wave generator. Yep had looked into that as well, was thinking about taking the ramping voltage right off the timing capacitor on a 555 astable and use the LM3914 in dot mode. only problem was i didnt have a 3914 handy so tried the nuts-n-bolts route using comparators (LM339), had lots of those. But the design became too complex and just plain overkill, so later dropped the idea (violated the KISS rule). But something worth looking into. Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 7, 2004 Report Share Posted May 7, 2004 Nettron,Don't use the ramping voltage of a 555's timing capacitor to drive an LM3914 because it is not linear with time. It would start counting the LEDs quickly, then slow down when nearing each end. The integrator output of a dual-opamp triangle-wave generator is perfectly linear. Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 7, 2004 Report Share Posted May 7, 2004 Nettron,Have you considered distorting the ramp so the LEDs slow down at each end like a pendulum? Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 7, 2004 Report Share Posted May 7, 2004 Don't use the ramping voltage of a 555's timing capacitor to drive an LM3914 because it is not linear with time. Remember i didnt have a LM3914 and was using LM339 comparator IC's. The idea i had in mind to solve the non-linearity problem, without adding another IC , was two-fold: 1. use different amounts of feedback around each comparators to "pull" the input voltage over threshold at appropriate timing intervals, 2. use a different reference voltage for each comparator. Yeah i know, it sounds ugly but that was 2 years ago and i havent looked at it since.Have you considered distorting the ramp so the LEDs slow down at each end like a pendulum?Hmm...interesting,hadnt thought of that. AG maybe you should post a design based on that idea,I for one would really like to see something original. Quote Link to comment Share on other sites More sharing options...
MP Posted May 8, 2004 Report Share Posted May 8, 2004 yes, audioguru, could you post an original design for others to view?MP Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 8, 2004 Report Share Posted May 8, 2004 The exponential charge/discharge of a 555's timing capacitor IS like a pendulum! But the effect is reduced by the 555's lack of full charge and discharge (1/3 of +V to 2/3 of +V).So maybe it would be best to low-pass filter a square-wave in order to obtain an alternating voltage that changes very quickly at the beginning and very slow at the end.What do you think about that?How many LEDs? Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 8, 2004 Report Share Posted May 8, 2004 Appearently not all that original .http://www.eki.com/product.asp?number=2009 Maybe add a few more rows of LEDs, with different numbers of LEDs in each row, to simulate the "string" with the longest row representing the bobbin at the end. Maybe this belongs in another thread ?So maybe it would be best to low-pass filter a square-wave in order to obtain an alternating voltage that changes very quickly at the beginning and very slow at the end. Appears do-able. Another option could be to build a circuit based on the internal window comparator on the 555 timer IC but with independent control over the charge/discharge rate and window reference voltages ( Vtrip upper/Vtrip lower). Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 9, 2004 Report Share Posted May 9, 2004 Nettron,Eki aren't using 18-pin LM3914s but are probably using the same circuit that you have, except using CMOS instead of your TTL. A quick check of Kinetics shows that a pendulum doesn't swing exponentially, but more like a sine-wave, since its inertia starts it swinging slowly, the same way that it ends when it runs out of momentum.What happened to KISS? You sound like an LED salesman. Those LEDs will be coming out of our ears! Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 9, 2004 Report Share Posted May 9, 2004 Eki aren't using 18-pin LM3914s but are probably using the same circuit that you have, except using CMOS instead of your TTL. I mean the pendulum concept not the type of IC's used, although cmos would be better when it comes to power consumption, especially if we're talking portability.What happened to KISS?Taking a backseat at the moment i guess, im sure it can be refined, perhaps use a sinewave oscillator to drive a 3914('s). Making it more analog rather than digital would be something i would be even more interested in.You sound like an LED salesman. Those LEDs will be coming out of our ears! ..and for todays special, 2 bags of LEDs for the price of 1 ;D yeah i can imagine a salesman's delight at someone designing a commercial circuit/kit with that many LEDs. Just more eye candy not really necessary. Quote Link to comment Share on other sites More sharing options...
Ldanielrosa Posted May 9, 2004 Report Share Posted May 9, 2004 Have you considered using a microcontroller for this? Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 9, 2004 Report Share Posted May 9, 2004 Nettron,I mentioned CMOS because Eki's kit doesn't appear to have LED current-limiting resistors. CMOS outputs current-limit at about 11mA from a 9V battery.I agree that linear will look better than logic, because the LM3914 "blends" between adjacent outputs, while logic will go: jerk, jerk, jerk, etc.Ldanielrosa,Microcontroller use also is not very original. I can purchase this circuit from my local car-accessory store and have a choice of LED colours. The product has a microcontroller chip under a blob of black epoxy, and the LEDs are surface-mount. It is supposed to make your car appear to have an expensive (and noisy) security system.Cell-phone covers also have many blinking LEDs. Quote Link to comment Share on other sites More sharing options...
MP Posted May 9, 2004 Report Share Posted May 9, 2004 I would tend to agree with LDanielRosa. A microprocessor would be a good way to go. As far as this not being original: Obviously a statement from one who does not program. That would be like saying that there are a lot of op amp circuits, so using one in a new design is not original. The code for a microprocessor will give you complete control of the LEDs in any sequence, pattern, brightness, etc. The program can be as original as you need for it to be - because you are writing it.MP Quote Link to comment Share on other sites More sharing options...
Nettron Posted May 10, 2004 Report Share Posted May 10, 2004 A microprocessor would be a good way to go. As far as this not being original: Obviously a statement from one who does not program I assume by "microprocessor" we mean a microcontroller, yes ive seen that suggested on other forums. A controller such as the PIC can simulate in software just about any logic circuit. I agree this would be a good option if the IC count and "wiring" become too great, but like MP mentioned thats assuming one is comfortable with programming. This has somewhat jogged my memory ( excuse the coming pun) ,managed to dig up an old schemy of a circuit i once used for proramming SRAM memory IC's. Its an option to using a micro and for programming eliterates, its programmed one bit at a time via a non-encoded keypad.http://www.geocities.com/nettron1000/2816SRAM.htmlOnly drawback is that the info will be lost when power is disconnected. A way around this problem would be to use EEPROM's. Quote Link to comment Share on other sites More sharing options...
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