How to make Chase Lights with a Decade Counter - The Learning Circuit

Karen is making a robot with lots of flashing lights. But the Arduino she’s using to control the circuit has limited I/O. After learning about 555 timers and decade counters, Karen discovered that she can combine them to animate the lights in her robot reducing the outputs needed on the Arduino from ten, down to one. Decade Counters use a clock signal to cascade a high output signal across 10 outputs. Karen shows how to make an astable oscillator circuit with a 555 timer to create the clock signal needed for the decade counter. Then shows how to set up a circuit with 10 LEDs, one for each output. She also shows how to use transistors and relays for applications that require a higher current draw: bit.ly/3fWekor
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[@pileofstuff]

the good 'ol 555 + 4017 circuit. It's a classic that every electronics hobbyist should learn. Nicely presented, Karen!

[@stevehyt]

A variation of this circuit, called a Larson scanner, was used for Cylons and KITT on Night Rider. Thanks for these videos!

[@Davedarko]

I know you can do 6 lights with the 4017+555 going forward and back - 8 is more tricky and involves more chips. Having it to stop between scans sounds even trickier.

[@ChadKapper]

You have taught me soooooo much!!! Thank you for your thorough yet digestible lessons!

[@albertogarciaengineer3053]

I love these videos, really well explained. Keep it up!

[@pileofstuff]

@0:46 I like the way you think. Throwing more software at it isn't always the better solution.

[@sortofsmarter]

Right...those chips wont crash and will run those lights for the next 100 years..long after the Arduino decided not to boot up one day..lol

[@berenedain8427]

I really love these videos, and I finished watching the relevant video hours ago, your explanations are really nice and the videos are calming as well some of my lecturers i have should take notes haha!

[@samzx81]

I hope you keep putting out these videos :)

[@Chubbbs117]

Great video, Ive always wanted to try stuff like this.

[@uzhavarasan4505]

Intresting video. Thanks sis

[@linod7265]

Thank You for your vídeo, It's really inspiring to make great things like the rain drop scene for My christmas tree, and to make the turning back lights of the car more visible. Thank You and hope to learn more from You.

[@Electronzap]

That's a cool circuit :)

[@MrCardeso]

Thanks, Karen!

[@DAVIDGREGORYKERR]

Counters like the 74AC74 can be used as part of a Tayloe Down Conversion Mixer, the other chips required is the 74AC00 and the 74AC152.

[@changarawemichael5556]

Thanks alot

[@TboneLoyal]

Great video. Learned alot. Guess you could use this to wigwag as well.

[@nathanherling9836]

Very neat!

[@FireballXL55]

I was surprised you got away without any decoupling across the 555 unless that is you used the CMOS version. The 555 really takes a gulp of power during switching and can cause problems.

[@iyup2964]

Nice channel!

[@stnwrd]

Great sound effects Karen, I use to drive my parents crazy with them LOL

[@arnelcondino2634]

Hi Karen 👍👍👍

[@nourn2002]

Car turn signals would be great with this

[@leecollins5479]

karen you make these videos even better watching!

[@elvielaelectronico]

Me gustan los efectos de sonido ( I love sound effects)

[@artursmihelsons415]

Try to put in positive rail p-channel Mosfet which gate are driven by npn transistor in place of relay.. :) From positive rail to gate add 100K resistor, npn transistors collector goes to gate, emitter to ground, from base 10K to ground and through 4,7K to arduino.. In battery powered application this will lower power consumption. To save space, I would put in place of these output transistors ULN2803 darlington array and maybe leave remaining 2 transistors.. ;) Anyway, great video, as always!

[@maker_karen1785]

Thanks for the input!

[@alansmithee183]

The Element14 Karen is one of the good Karens not one of the bad Karens :)

[@andrealvs]

As a newbie in electronics I find Karen's videos fantastically easy to follow. Thank you for putting in time into make them! One question about this circuit: why did you decide to use a relay to turn the circuit on and off instead of a transistor, like you did to drive each strand based on the decade counter?

[@maker_karen1785]

It's been a bit since I worked on this, so I'm trying to remember back. For the rest of the robot circuit that this is going to go into, there are other circuits that turn on fans and vacuums that have a much higher current draw, so I'm using relays for those rather than transistors. I think I just decided to use a relay here as well so I didn't have to worry about max voltage or current draw at all. I think relays can also handle heat dissipation better than transistors, so that may have also been why.

[@RealRapBeats]

hay qua nha ban!

[@michaelrobert4094]

Could turn the relay circuit into a latching circuit. It would be easy to turn this circuit into a knight rider scanner

[@stevetobias4890]

This is really cool. I just have one comment, you started all this because you were using 10 wires from your Uno board, how many extra wires are you using in the circuit. I understand about the co adding but there is an example in Arduino IDE that does this, however, if you're doing it because you need the extra Arduino pins in your robot project then it makes sense. If you only need a set lighting speed you can cut out the 555 right,?

[@eswar9255]

yeah

[@walter_mayer]

@6:50 what you are doing here? Put the IC output without resistor to the base and the emitter to GND. So the only resistance of the circuit is the IC internal FET resistance. Or with other words you produced an nearly a shortage to ground at each output. I would recommend to use a 2N7000 FET to avoid such issues. @8:39 with the switch it's ok. But mention to connect the relay to an arduino pin without showing the necessary free wheeling diode could kill some arduino or running in a latchup risk. It's anyhow no good idea to connect a relay directly to an uC pin. I would recommend to use a big enough P-FET to turn on the circuit, by switching the arduino pin to low (for turinging on).

[@cncpreferred848]

That is an easy circuit using the 555 and 4017 for only 10 lights. What do you have for 20, 30, 40, or more lights?? I have tried a few circuits on the internet for 40 lights, but there were 4 lights on at a time, and they ran together as a group. I would appreciate the circuit.

[@alfredsivanzire3552]

😍

[@RepTalez]

Çould you instead connect the LED anodes to the output pins and connect all the cathodes to ground through a single resistor? It seems to have the same effect and takes up less space, but is there drawbacks to doing it this way? This is for the single LED per pin.

[@maker_karen1785]

I responded to you on the element14 Community. ;-)

[@phs125]

I wish I chose engineering all those years ago. This thing could've been my job😭

[@chriso5355]

Anybody know the easiest way to make runway approach lights chaser?? This is for my small airport on my sheet of plywood... I was thinking about having 6 groups of 4 White LEDs over about a foot or so in length.. Thanks

[@genebowdish.mageniemagic]

Sounds like it is possible to run 10 lights with 1/10th of the power with a fast enough frequency which may be beneficial for a solar powered system and a cloudy day ... Study by, Gene Bowdish

[@josecarlospereiramachado2016]

Muito bom, sonoplastia melhor.

[@blackBird5869]

Your students are to lucky who have a super genius like you

[@krisc1243]

Hi, thanks for uploading such a great video. If I understand it right, each NPN transistor works as MOSFET to utilize separate power source to compensate over drawn current ?

[@josefonseca9178]

I think there is a better way to do this but, if you are going do keep the relay i would suggest doing a seal-in contact, unless you want to keep holding that button all the time. Loved the video!

[@maker_karen1785]

Oh yeah definitely. That was just for the demo.

[@thatroom]

your voice is asmr for me, Karen.

[@PedroSantos-mk3pm]

It is great...think i can build a real robot drone with that...a block RF attached to the input...Lets go fly...Think about it!!!!

[@Davedarko]

You can use the 4017 as a crude stepper controller, but I'm not sure the stepper is fast enough to levitate things with a prop, unless you are building an ornithopter. There are ways to convert the rc pwm signals into clock pulses for the 4017 then and bam - flying 4017.

[@arnelcondino2634]

Pls give me a schematic diagram

[@maker_karen1785]

I drew up the breadboard design, but I didn't make a schematic. You can find what I posted on the element14 Community. Link is in the description.

[@canlobin2240]

i like you

[@IanG-uf2fq]

THE EVERLASTING BAD HAIR DAY

[@kashyapkoshti]

just add D-flip flop and you don't need an arduino at all

[@DaveMcAnulty]

I don't understand the requirement of the relay. The 555 timer only uses a few ma of current while running. The decade counter, transistors and leds can all be powered off the power supply lines, no?

[@rohankumar5461]

If relay is not used then whole circuit will run from one Arduino pin which can only supply 20ma

[@cdwlights]

I wonder why not use an arduino pin to drive the clock enable pin on the counter

[@maker_karen1785]

@@cdwlights You could, it just would require an additional Arduino pin. The idea was to run the entire circuit off one Arduino I/O and only have to do as much programming as having to turn the circuit on/off.

[@techinfotahir7912]

Agiya sawad ab to