Knight Rider K.I.T.T. Scanner

[CocaCola]

Okay that sounds good. Could you explain how I would wire up this entire circuit with the LEDs and such. Also how would I switch between preset designs?

Have you decided upon a design approach since many have been offered? As for how you wire it up and how you switch patterns is fully dependent upon the hardware you choose and the firmware you write to run it...

On a side note, I have no idea where you live but in most US states lights in motion (less turn signals) on a vehicle that is not an emergency vehicle are illegal...

 

[KrisBlueNZ]

As long as the code isn't written in BASIC or something like that, the dimming effect can be done easily enough with PWM. Even if you're using 74HC595s and bit-banging the SPI, PWM is feasible. True, it adds a fair bit of complexity to the firmware.

 

[CocaCola]

As long as the code isn't written in BASIC or something like that

Can you elaborate why you suspect you can't do this with BASIC, as I have done this in BASIC so I'm confused as to why you would say you can't?

The overhead on the micro just gets out of control real quick and make it impractical, IMO not worth the trouble when you can easily slave the control to an LED driver chip and get superior results...

 

[KrisBlueNZ]

Just because all the calculations for pulse-width-modulating 30-plus LEDs would be far too slow in an interpreted language. If you're talking about compiled BASIC, I would agree. I was really referring to the BASIC Stamp and the like as being impractical.

The overhead for pulse-width-modulating 30-plus LEDs with, say, 8 or 16 levels of brightness would not be an issue, provided that the code was reasonably well designed. Sure you can use LED driver chips to do the dimming, but where's the fun in that?

 

[CocaCola]

Just because all the calculations for pulse-width-modulating 30-plus LEDs would be far too slow in an interpreted language. If you're talking about compiled BASIC, I would agree. I was really referring to the BASIC Stamp and the like as being impractical.

OK, agree but interpreted BASIC is soooo 20 years ago With compiled BASIC and the ability to do inline assembly today's high end BASIC compilers are arguably just as efficient as any compiler out there...

The overhead for pulse-width-modulating 30-plus LEDs with, say, 8 or 16 levels of brightness would not be an issue, provided that the code was reasonably well designed. Sure you can use LED driver chips to do the dimming, but where's the fun in that?

We all know you like doing it the hard way, on the contrary I'll fully into taking the easy route especially when it's become so cost effective to do so...

As an example I have been using the HT1632C for a ton of recent LED projects, control of up to 384 independent LEDs with 16 levels of brightness, all for just over a $1, and I can control it with the most basic low powered micro, have plenty of CPU left over and only use 3 pins... It's simply cost and time effective, even if it's not as fun

 

[BobK]

I would take the hardware minimalist approach. Looking at the datasheet, the Vss pin can sink up to 340mA. That would be 17 LEDs lit at 20ma -1 for the mA or two needed by the processor. So, I would keep the number lit LEDs down to 10 at any time (and socket the chip in case of software error). You could get quite good trailing effects with 10 LEDs lit at a time. In fact, you could probably have all of the LEDs lit at different levels with clever phasing of the PWM signals.

So, my hardware would consists of only the 40-pin micro, a resistor for reset, a couple of decoupling capacitors, 30 LEDs and 30 current limiting resistors, plus the ICSP header for programming.

Bob

 

[KrisBlueNZ]

Ditto Bob. And good suggestions there.

I don't necessarily "like doing it the hard way"; I prefer to have the complexity in the firmware, where there's no per-unit cost, than in hardware.

 

[kevbo423]

I think I want to go with the 40 pin Micro controller approach. What else would I need besides the LEDs, and the microcontroller?

 

[(*steve*)]

I think I want to go with the 40 pin Micro controller approach. What else would I need besides the LEDs, and the microcontroller?

Resistors, and a program (oh, and a programmer, a PCB or a breadboard, a power supply, possibly some bypass caps, maybe a crystal and associated components for the oscillator, etc.)

 

[medictrode]

How about an arduino? I know hard core Micro guys hate these things, but they are great for single use projects like this especially if you are a beginner. I would assume though you would need the Mega board as it has more pinouts on the PWM side of things, unless you use the digital with some sort of small R/C Circuit to get the whole trailing effect thing. Just a thought..


Actually just last week I found a bread board with this exact effect I made way back in Vocational school(18Yrs ago, wow I'm old). I tore it apart because I needed the breadboard, but it was quite the complex circuit. I think there was around 5 ICs on there..

 

[(*steve*)]

Well, you could use an arduino, or simply an ATMega-xxx, the chip used in an arduino board. And you can still use the same development environment if you wish.

 

[JonBoy470]

I can see why purists would hate Arduino, but I would agree with medictrode this project is the sort of thing Arduinos are great for. Using Charlieplexing, you can drive N*(N-1) LEDs using N IO pins on the Arduino, so even an Uno or Leonardo should be able to drive all your LED's. This ground has been covered by the Arduino community; there's dedicated libraries for seemingly everything... Charlieplexing is no exception. Check the links below to get started...

http://arduino.cc/forum/index.php/topic,8461.0.html
http://playground.arduino.cc/code/charlieplex
http://www.instructables.com/id/Controlling-20-Leds-from-5-Arduino-pins-using-Cha/

 

[JonBoy470]

Or if Arduino is too rich for your blood...

If Arduino is too rich/mainstream for you get a TI MSP430 Launchpad right from TI. Use TI's free development software, or download Energia, which is a fork of Arduino targeting the TI Launchpad board... Community isn't as big, so software libraries aren't as plentiful, but the chip is crazy low power, and it and the Launchpad Eval board are way cheap... ($10 last I checked)

http://energia.nu/
http://www.ti.com/tool/msp-exp430g2

 

[sheldonstv]

build yourself a standard 4017 counter circuit and connect this circuit as shown to each op