2 Ways to make a Larsen Scanner - DIY Electronics for Beginners

2 Ways to make a Larsen Scanner - DIY Electronics for Beginners
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In this video we look at two ways to make a Larsen Scanner (leds that chase up and down a row). the first using an Arduino, and second, using discrete components, in this case the 555 & 4017.
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[@gartmorn]

Great Paul. I love the unedited, warts and all approach. I wonder how many other you tubers edit out all the 'real world' electronics! How boring would it be if every circuit worked first time! 🤣

[@pulesjet]

Yep Chit happens. EVERY TIME.

[@ericsmith7988]

Lol as I was watching I kept saying you need more diodes and then you put more diodes in. I like this project. Thank you for the video, Paul.

[@karlporath8904]

I did this one on my Heathkit Experimenter with a 4017 in April when we were shut down. After spending a couple hours in my shop I showed my Wife proudly. She rolled her eyes and asked what else it does.

[@BertGrink]

I hope you told her that it's not so much about what it does, as it is about the fun you have building the circuit.

[@bblod4896]

I feel your pain.

[@BrucesWorldofStuff]

Wife's, what ya going to do? :-) They sure know how to go what! LLAP

[@virgilharsell7463]

Promise us when you are a big famous KZbin star, you will still leave in all the troubleshooting. I learn so much just from that. Thanks, Paul.

[@ericmartin9299]

"We've got a little bit of crazy going on there." - describes most of my circuit builds. LOL

[@learnelectronics]

same here, I know what I want it to do, but it never does the first time....

[@adamv242]

Thank you for this! I'm going to try breadboarding this up myself as soon as I get my hands on some 4017s...

[@rjmendoza]

Honestly I learn more with you than I ever do in something scripted ... you have a new sub lol well also besides, your almost at 100k AND your about to have a needle shoved in your ear drum lol

[@learnelectronics]

Awesome, thank you!

[@HarrieWorst]

It gives a throwback to the great '80s television series like Knightrider, Airwolf, A-Team and McGuyver. And cheesy lighting effects for home use at that time. What is not to love about it! Certainly for me as an '80s born and raised kid.

[@loucinci3922]

Enjoyed the heck out of that. Thank you. On the fly troubleshooting + redesign. Good job.

[@mikeoliver3254]

This is such a fun circuit to build and play with, I’m going to have to see how many ways I can build the scanner with the stuff I have on hand. Great video Paul, can’t wait to see you hit 100,000, you have earned it.

[@michaelpadovani9566]

Enjoyed the troubleshooting process, only thing I can think of is maybe poor breadboard connections? Cool mating of 2 ICs for a neat LED effect.

[@moebiusfan9545]

Always enjoy seeing projects from the ground up! Especially the foibles and uh-oh moments that require troubleshooting and redesign. Great learning exercise!!

[@frankowalker4662]

That was so entertaining, Thanks Paul. Don't you just love the randomness of Breadboards. :)

[@BrucesWorldofStuff]

Yep! If it is not working just give it a twist and there ya go! Working... Lol LLAP

[@markday3145]

The two main problems appeared to be wiring two outputs together (which is why he needed all the diodes), and leaving the reset pin floating (which is why it suddenly became stable at the end).

[@GORF_EMPIRE]

Discrete way is much better than wasting an entire UNO on it. I'm sure fitting that on a small PCB smaller than the UNO would be relatively simple as well (hint hint...nudge nudge) ....unless you add some relays to control some high current LEDs and stuff it on your cars front grill.

[@umbra3324]

Learned a lot. Thank you

[@utkf16]

Good timing I found a 4017 sitting about just yesterday. Great video thanks

[@belfieldsucks]

Ha, that was great Paul, i do love that you leave in the trouble shooting aspects of it. It totally reminds me of myself at my desk, rarely works the first time. I had mentioned some weeks ago about a soldering station i was building, oohhh man did that go in and out of its enclosure to many times before i had it right haha. Keep em coming Paul, i haven't found a video yet that has'nt taught me something!

[@KissAnalog]

Thanks Paul fun video!

[@bblod4896]

8:43, "We got a little bit of crazy going on there" ROFLOL

[@mazharkhaliq1971]

Really good video 👍

[@johnscoles660]

Did you connect the decoupling capacitor between pin 8 and 1? Would be a great vid on what they are for. Love this one, yet more time to waste on the 555

[@BrucesWorldofStuff]

That is great Paul! That is the way it works on my bench too! :-D I have come to notice that my OCD and or dyslexia gets in the way at times. Like you said, Who in the hell came up with that combination? I love the fact that you build in the diagnostic into the video like it was a accident. That is a cool way to make a video... Lol Just pulling your leg a bit! I know, what happens at the bench stays at the bench! Right? Thanks for leaving in all the Oops and the video... I love that circuit. Someday I will build it... :-) Will they come? LLAP

[@monkeymanstones1]

Hope my Twitter post added subscribers. Today's video was and wasn't a great start for the new viewers. "Was" as some viewers will recognize the debugging steps taken to resolve the problem, wasn't as some may see it as badly done (clearly it wasn't, just needed completion which was in effect debugging today). A good video.

[@samuelchamberlain2584]

You can buy smd practice boards with this circuit. I managed to cook all the leds on mine and ended up adding though hole to get it to run.

[@bblod4896]

Now, if you can get it to talk and drive a car, I'll be impressed. 😆 Thanks Paul.

[@opalprestonshirley1700]

Enjoyed this video, a tribute to all those LED lighting effects. Fun watching you troubleshoot.

[@jamesallen6007]

Thanks.

[@georgechambers3197]

Live TV, almost. 😁 Discrete components are fine but I think I'll stick with the Arduino. I have more of those than components. Thanks, Paul great video!

[@midnightrizer]

What circuit do i need to calibrate my O scope? is there a built in calibration on scopes or do i need to build a circuit to do that?

[@JasonQuackenbushonGoogle]

this is great. do you just add a cap in front of the anode of the LED to get the trailing effect? if so what are some good values to play with and can you show how to do the math based on the clock rate of the 555? and is there a sweet spot you can calculate between clock rate and cap drain to get that cool cylon eye animation effect? basically im saying coukd you do like half a dozen more vids on this circuit? ;)

[@ELECTROMOD]

I really enjoyed the way you troubleshoot and did it. I have a question for you. While going reverse i.e from pin 1 to pin 6, why can't you connect those pins to the cathode of the diode instead connecting it to the anode of the same diode? so while in the reverse LED chase the forward corresponding pins i.e from pin 3 to 10 won't get any effect from it. I'm right?

[@joejane9977]

when the chip is not outputing V it is sent to ground so like pin 4 and 5 are bridged trying too drive center led the other pin is pulling it down so you cant pull it up too drive the led. before you double isolated.

[@learnelectronics]

yep

[@ianbertenshaw4350]

Now i wonder if you use an arduino running a sketch that fades the previous led as it brightens the next would it look like the eye on a cylon ? Might need to run the leds hard up against each other ?

[@learnelectronics]

Yep

[@rogerhammelsr.1788]

Come on Paul everything doesn't work the first in your world. Must be moving over to my world. Great Video

[@keithking1985]

i knew you'd throw in a scope at 100k!!

[@josephmazzeo9413]

Breadboard contacts especially the cheaper or heavily worn ones will be flaky at best. After so many insertions they lose their grip on the leads and wires.. the cheaper ones are horrendous out of the box.

[@stevetobias4890]

This can be done with a trail using an Arduino, you will need two pins for each LED and each LED has two resistors, one that shows a faint glow (half on) for the LED and the other bright glow (full on). Then the Arduino just goes between full on, half on an next full on etc.. there's your trailing effect like the real KIT's car Larson effect

[@learnelectronics]

very nice

[@jamest.5001]

Would a cap per LED, give The trailing effect?

[@Namirred]

JAMES Just James I can't see why not

[@lubricatedgoat]

Would a capacitor help with the afterglow? I mean one for each LED in each direction? Or would it slow the brightening stage too?

[@learnelectronics]

It might. Ill give it a try

[@JasonQuackenbushonGoogle]

learnelectronics seems like you'd just have to play with the clock to start charging the cap earlier?

[@jamest.5001]

The kitt scanner!

[@pulesjet]

Use your NE555 to Drive a Shift Register for the same effect. Dhoooooo No way to reverse order. Guessing the Firing order was dictated by the way they could layer the tracks within the IC. Yes, They could have made life easier, eaaa?

[@learnelectronics]

You know engineers, they aint right

[@pulesjet]

@@learnelectronics That's a given. They love to create 9 more problems solving one.

[@BrucesWorldofStuff]

@@pulesjet So true! I know 2 engineers and they always do it the hard way... LOL LLAP

[@g8sbs944]

You have dirty connections clean the leads

[@nonsuch]

I'm not trying to be a smartass but the 555 timer and CD4017 IC chips aren't "discrete" components.

[@learnelectronics]

What I meant was not a microcontroller.

[@nonsuch]

@@learnelectronics I know what you meant. Maybe I was being a smartass. 😂 Love ya man!

[@gerardregnier3457]

The first thing that should have been done was to APPROPRIATLY de-couple the integrated circuits. We immediately saw tremendous spikes on the square wave output. This problem should have been addressed and mitigated before progressing further. You added de-coupling capacitors after the fact without understanding or checking to see what value or type of capacitor was best suited to fix the problem. Additionally, no effort was made to try to identify the cause of the apparent intermittent circuit condition that occurred. If a more complex circuit was being breadboarded, it would be highly unlikely that successful operation would ever be achieved without logical and diligent circuit checks and analysis performed during construction.

[@learnelectronics]

Lighten up, Francis

[@gerardregnier3457]

@@learnelectronicsWho is "Francis?"

[@smacks999]

Gerard Regnier Watch "Stripes".

[@jonelectronics510]

@@learnelectronics I think there are some good points being made, not wishing to criticise. This would have been an ideal time to show the 555 datasheet, discuss the section it has about decoupling and then further that to why it's needed. You could have then used the recommended capacitor value and scoped that and assessed whether or not you felt that was a good value. The output waveform showed the spikes that would have also been on the power rail caused by the 555. The 4017 was largely suffering due to the power rail instability but as mentioned, the random spikes on the 555 output should have been discussed and dealt with. The scope result would have been inaccurate to some extent due to the large loop area presented by your probing techniques.

[@gerardregnier3457]

@@smacks999 Read Hans Christian Anderson's story about "The Emperor's New Clothes."

[@borayurt66]

Seriously... Leaving the reset pin floating on a logic IC? Connecting different level (one low, one high) outputs together creating a perfect short? Then adding diodes to prevent this, yet still connecting the outputs at the same end of the diode which actually makes the diode useless and create the same short? You should rename the channel as "Learn electronics along with me"...