Instructables

Knight Rider Circuit For RC CARS - COMPLETE & WORKING - Updated 15th March 2012

Picture of Knight Rider Circuit For RC CARS - COMPLETE & WORKING - Updated 15th March 2012
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This is a NOW COMPLETE & OPERATIONAL !!

Just waiting on a capacitor and a 1k resistor to complete this instructable and i will also be adding a Variable POT not origionally included in the schematics but i will want to mount this onto a perfboard of the smallest possible size and because i have only just started learning electronics - the only way i learn is to throw myself in at the deep-end, so to speak!

Ive left Pictures of the ingredients as well as a list below for what you will need to procure for this awesome and inexpensive little circuit !!!!!!

1x NE555 Bipolar Timer
6x LED (Red)
8x 100R Resistor (1/4W)
2x 220R Resistor (1/4W)
1x 1K Resistor (1/4W)
1x 68K Resistor (1/4W)
1x 3.3 uF Electrolytic Capacitor (16V)
1x 4017 Decoded Decade Counter
1x 9V Voltage battery (also known more commonly as a PP3 Battery {i didnt know this!})
1 x 9v Battery Snap/Clip/Connector/whatever, lol

I bought EVERYTHING ABOVE from EBAY !!! - Nice & Cheap ! NOTE: if you buy resistors, best get them in packs of 100 or it is not worth buying them !

I cannot take credit for the full schematic of this circuit which you will find here and also an awesome forum for people like me who either have NO knowledge of how to put something like this together or that are learning electronics themselves - and if you really want to make this circuit yourself, please get involved in the forum here where you too can learn from the best there is !!!

This is now Fully-Complete, If you want to make this for yourself and dont want to see my messed up tries, skip straight to Step 4 !

 
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judas791 year ago
I have an Arduino, but making a Knight Rider light using it would have been to easy, and Arduino's aren't as inexpensive as this project. So far I've put together the breadboard version, but I'm going to put a pot. in the R2 position as you did, on a perf board. I'm relatively new to electronics also... Have you tried using 12v? Is it brighter or just last longer? I'm supprised you haven't gotten more response. Thank you for all pics and work you did on this.
offtherails2010 (author)  judas791 year ago
im so sorry for the really delayed response to this, ive been in and out of hospital all year so havent really had must time for anything !

Thanks so much for your praise ! Really is highly appreciated !

Im also into the Arduino Scene, only just got back into electronics after a 15 year lay-off lol !

Yup, ive also tried this circuit from 12v and all that happens is the 4017 decade counter gets a little hotter (around 45°c instead of about 35°c when running from 9v) and the circuit lasts longer !

Once again so sorry for the really late reply !

I should be bringing out a few PCB's for these knightrider circuits specially for RC Vehicles, some ultra small ones using SMD parts as well as through-hole components !!

My layout of your instructable is still laying on my breadboard. I bought more breadboards. I tried to get a clean layout using Fritzing but never did. I come to this site all the time but never noticed the message notification until today. Did you ever make the PCB's or get them manufactured for you?

I just finished building this circuit and it works, but it seems to kind of run over both of the second to last LED's on the left and right but when sped up with the variable resistor it looks normal.
do you absolutely need the resistors that go behind the led lights? because i dont have that many of those type of resistors and was wondering if i could take them out.
You could but you will be shortening the life of the LED's - You might even BLOW them instantly !

The Resistors limit the voltage going to the LED's, you can use anything from 680 Ohm to 1K resistors, its always best to have them in there also depending on what colour LED your using the resistors will need to match the VFD rating of the LED's...

Do you know the forward voltage of the LEDs your using, and i'll calculate the needed resistors you need for them ?
Hey thanks for the reply! I didn't know that they could blow like that either! lol,
yea the LED's that I'm gonna be testing the circuit with can run with nine volts and there on this kit i have so i think they all ready have resistor in them. When i finish the circuit on an actual board I'm gonna have to get different LED's because i can't take those ones off the kit so i think ill have to get some more resistors for them. Thanks for the help!.
No problem and your most welcome, anytime !

Just let me know closer to the time for when your ordering the LED's and i'll offer some suggestions !

i buy things like resistors, usually, in batches of 100 from ebay, depending where you are in the world, it only costs about £2 or $2 including shipping/postage from within your own country !

If you cant find the right resistors or you live in a country where they charge stupid amounts for things like dirt cheap resistors, just send me a private message and i'll send some to you, got pretty much every value lol !

This kit with the 9v LED's sounds interesting, do you have a link from where you got them by any chance ?!?
Thanks! and yep i found a link to the kit i have, it also comes with a bag with resistors and about 14 different ic chips and and all that stuff the LED's that can handle nine volts are built into the board, here's the link to it in case you wanted to check it out http://www.radioshack.com/product/index.jsp?productId=3814337#
and it also comes with two books with a bunch of other circuits in it
Ahhh nice1 for the link, i just had to be sure lol !

I suspected that the LED's may not have been able to handle 9v on their own and i was correct, lol !

Okay so if you attempt to power these LED's with anymore than 3v then you will definitely blow them !

But the colour of the LED's also correspond to the voltage needed to power them, typically these are the ratings for the colours below:

Colour Voltage

Blue 3.2v MAX
Green 3.0v MAX
Red 2.2v MAX
Yellow/Orange 2.0v MAX

If your unsure, always use a 1K resistor for powering up an LED, if your using a normal breadboard and not this electronics lab, then its real simple from there, drop the ohms in small increments if the LED brightness is too dim for your liking:
so for example,
Use the 9v battery, attach a batter clip onto it and put the wires into a standard breadboard then:
choose a red LED, hook up the positive red wire to your breadboard and the 1st leg os a 1K resistor, second leg of the 1K resistor to the Long Leg of the LED (Anode) then the Short leg of the LED to the black wire of the 9v battery (Ground, or GND for short) and the LED will be quite dim, because Red LEDs typically have a forward voltage of approximately 2v, ish...
Then disconnect the power from the LED and change the 1K resistor to a 680 Ohm resistor (or any resistor above 700 but doesnt have a 'K' after it !) the K stands for 'thousand' so a 1K resistor is basically 1000 Ohms.

If you keep adjusting the LED's resistor like this till your happy with the brightness of the LED then you will never blow an LED, although, LEDs are so cheap nowadays and accidents do happen, i only recently blew an LED lol ! (just yesterday !) but thats the 1st LED ive blown in YEARS lol !

Like i said, accidents do happen lol !
wow thanks i never knew the voltage ratings of the LED's before! i just assumed that every one was just different and almost any voltage below 9 volts would work lol, that helped me understand how to find the right ohm resistor for LED's in the future, lol just yesterday I found out that infrared LED's dont much like 6 volts on there own it lit up a bright orange, made a weird noise then gave off this odd smell next time i get a tv remote i will remember to use a resistor before the LED lol
Homer1002 years ago
Thanks for the Knight Rider Circuit !!!

Ive made one !!!

Many thanks !!!!

Homer100
offtherails2010 (author)  Homer1002 years ago
Your most-welcome !!!

I'm really glad someone's tried out my instructable !!!!!

;-)