Making A Custom Sign With An Atmega328P

[@W1RMD]

I love it! I love the vintage 70's cartoon look. Great job!

[@wiseoldfool]

You and Clive sound nothing alike, but you both have voices that are both soothing and engaging!

[@mangamaster03]

I love the sign, your choice of yellow LEDs, and the full walk-through of your design. What a beautiful project!

[@baratono]

Greatly enjoyed this project! More please.

[@FranLab]

Okay. You got it.

[@tookitogo]

11:40 Pro tip: the Atmega328p is perfectly happy with a supply voltage of anything between 2.7 and 5V for the full 16MHz. (The Arduino environment programs the fuses for a 2.7V brownout detector.) This means that 3 AAs in series (alkaline or NiMH) drive it beautifully with no regulator or diode drops or anything. At lower clock speeds you can go even lower, but that’s harder to set up in the Arduino IDE. Of course, if you need to interface with other devices you may not be able to get away with this voltage range, but most 5V-capable CMOS stuff is happy with it.

[@dhpbear2]

12:23 - I experience that same 'pressure-sensitivity' with LEGO-building!

[@vjcodec]

Epic! I would maybe stick another piece of foam in the same shape of the arrow on the back side! More body more protection. ;)

[@FranLab]

I wanted the back to be visible when I hang it up for curiosity sake.

[@ethanpschwartz]

@@FranLab And we curious folk appreciate that 🙃

[@nutsnproud6932]

I liked the voice over and time-lapse too.

[@idio-syncrasy]

Wow. That's amazing. ❤

[@absurdengineering]

To drop half a volt with the load you got, one Schottky diode would have been enough. Two 1N4007s do drop half a volt - with a 10Mohm load of the multimeter. The diodes are dropping about 1.3-1.5V under led load. The leds would be a bit brighter too :) That atmega will do fine on 5.5V, and those cells won’t stay there long either. I’d probably just leave it be without any droppers. Or instead of a Schottky use a saturated 2N2222 on the negative side - it’ll drop 0.2-0.3V, adding more than enough margin to keep it within the voltage ratings of the ATmega.

[@appliedengineering4001]

It's nice to have margins there. Even though the atmega chip can handle 5.5 volts. it can be damage if the voltage hits 6 volts. Plus, what happens if someone put alkaline batteries in there. Then you're looking at close to 6.5 volts.

[@absurdengineering]

@@appliedengineering4001 A fuse in series with battery input and a TL431 with a current boost transistor will do the trick :) Set to 5.7V. Anything above it will shunt the voltage, and if the source is feisty, it will pop open the fuse. Do not use poly fuses - way too slow. Single-use fast fuses work.

[@MatthewSuffidy]

So there were enough GPIOs to just switch the LEDs without any multiplexing? To my knowledge the Arduino classic has a maximum total amperage which you would probably approach with so many LEDs. What you can otherwise do is switch a supply rail (with transistors) using the GPIO signal to avoid that.

[@jannepeltonen2036]

It's completely mesmerizing to watch you work on this. I mean, it feels like a privilege to see the working methods of someone of your experience. Thank you!

[@henrysara7716]

Thank you, great / funny project.

[@bernielarrivee5448]

Very cool. I always learn something new watching you work, which is really saying something since I've been working with wiring and electronics for decades. Color me a fan, Fran.

[@danielsanichiban]

Think of the signs in Las Vegas back in the day, or some of the more elaborate discos. How many Watts were they dealing with? were there giant banks of relays clicking away somewhere? motorised multipole switches like pinball machines? could be a cool video topic ....

[@tvelektron]

Never liked those yellow leds in the 80s and 90s, always used green and red that time. Later i went to blue and coolwhite because they have been kind of extraordinary and novel for some time. But this sign is so beautiful that i want to get some of the old yellow ones now...

[@wiseoldfool]

Blue LEDs? we used to dream of blue LEDs!

[@tvelektron]

@@wiseoldfool with "later" i mean the early 2000s. I cent remember the exact year, maybe 2003 or 4 i got my hands on a nearly complete spool of blue SMD LEDs. They came from a board manufacturer and should be thrown away because of the wrong package. I think about the same time the chinese ebay sellers started with kind of affordable white leds as well.

[@michaelmoore7975]

I like using the double-sided 3M super strength molding tape. It is truly diabolical. Watch out wherever you stick it.

[@-jeff-]

Ugh. Yeah, I hated chassis wiring too. And I caught why you mounted the power switch on that center piece of foam. So it would clear the switch's throw.

[@_BangDroid_]

Really inspired me Fran and got my creative juices flowing! I've been trying to think of a new project and I think I'll make something similar for my friend's home theatre. I think I'll use neopixels and one of the pi picos I have laying around to save some weight and wiring complexity

[@CARLiCON]

cool signage & nice EEVblog DMM Frannie...can't wait for Franathon, even though I don't know what it is

[@D.E.Middleton]

As i do one thing, i do all things…. Nice work !

[@UpLateGeek]

Cute! I love the light chasing effect, like the old-school signs they had in amusement parks.

[@fazergazer]

So…what’s on the Big Screen❤😊

[@eDoc2020]

You could've used a 4017... but then you'd need a shitton of OR gates to get your desired effect. The trendy thing would probably be a dual core 133MHz MPU running Python driving a preassembled string of addressable RGB LEDs. The bare ATmega was just fine.

[@appliedengineering4001]

Or even better yet. just use a esp8266 running a web interface and Neopixel. then connecting it to a string of ws2811 pixels.

[@eDoc2020]

@@appliedengineering4001 ESP8266 is old now. ESP32 is the more modern equivalent. If it wasn't clear the 133MHz dual core MPU I was referring to was the RP2040 in the Pi Pico.

[@LanceHall]

You can take your dinky fake light bright and put in tri-color LEDs where the pegs go and make an active color display run with an Arduino.

[@lordmuntague]

Legend! Classic Fran build, I love t! ❤

[@thelegalsystem]

Those old LEDs have some character, a je ne sais quoi.

[@xuthnet]

As to worrying about frying the ICs, in my work with dozens of Atmega based Arduinos, I've never killed a single one. This includes an awful lot of abuse. My experience is that they stop working when they're left sitting in something and are fully immersed in rainwater but as soon as you pull them out they start working again (immediately, well before they're actually dry). And somehow I managed to do this several times. Some of these (that have been fully submersed) have also been subjected to burning man (without any enclosures). They're old tech built with modern fabrication techniques so they're completely overbuilt. On the other side of this coin is that I've fried a couple of ARM based microcontrollers just by looking at them wrong.

[@klif_n]

Pretty clever way of doing the chaser lights without a crap load of pins. Fun to watch :)

[@Tubemanjac]

English subtitles, please. 🙏

[@davepost7675]

I love the mix of "arts and crafts" with modern tech...wonderful. Looks great!

[@trainliker100]

Fran has an interesting combination of both the creativity of an artist and technical precision of an accountant. Those two traits don't usually both exist strongly in the same person.

[@flossflink]

Did you consider a cheap Chinese pcb?

[@mikemike7001]

Those cheap Chinese PCBs are fine in some cases, but why bother for a one-off, especially when you've had decades of old-school soldering experience?

[@eDoc2020]

That's not the Fran way. If she wanted a custom PCB she would etch it herself.

[@iancrowe8384]

Hi Fran. Nice project. A couple of thoughts. You didn't need to use the crystal oscillator, You can programme the 328P directly using the ICSP programming method. This dumps the firmware direct to EEPROM without the need for a boot loader. It would also mean that you don't need to swap the chip back into the UNO every time you want to change the firmware. You will need to add the ICSP port to your board (8 wire port, it's basically a SPI connection). The Arduino software supports programming via a ICSP programmer. You may need to hunt around for a tutorial on how to use the Arduino IDE to configure the fuse bits to allow you to use the internal clock but not a problem with your board as you've already got the 16Mhz clock. You can configure your UNO to act as an ICSP programmer but I'd recommend picking up a USBASP module which plugs into a free USB socket. They only cost a few dollars ($5-10) and are available everywhere. If i remember correctly you can configure the IDE to generate the firmware without the boot loader which gives you an extra 0.5-1.5k of programming space. As to anti static precautions I can tell you from experience it does make a difference. ESD (Electro-Static Discharge) is not only a device killer but also leads to device degradation leading to early component failure. One place I worked at introduced full Anti-Static Precautions (wristbands, conductive surfaces, conductive transport bags and racks and anti-static packaging. Over the next year we saw a 10% drop in final test failures and a 30% reduction in component failure based warranty returns. It more than covered the costs incurred. Ian

[@PicaDelphon]

Easy and Simple Build, I love these..

[@mikemike7001]

I have a surplus of Arduino Unos, so I might have just stuck one of those to the back. Would it be too heavy? Even though I have more Unos than I will ever use, I would have felt bad about stealing its ATmega328P. Then I remembered I could get an ATmega328P preprogrammed with the Arduino bootloader for a few bucks from Adafruit. Now I don't have to feel bad for a poor little Uno without its chip. The things nerds worry about.

[@FranLab]

I did not want a development board in the permanent sign, since it contains way too much unused electronics (power supply, UART, LED's, etc) that would just suck power. Dedicated basic board means lean, mean, clean.

[@mikemike7001]

@@FranLab I agree. I have gone so far as to move some Arduino projects to an ATtiny84 or 85 to make them as compact as possible as long as those chips have enough I/O pins. Not necessary for your sign, of course. BTW, I love that it's battery-operated. I'd hate to see it with a dangling wire. It really is beautiful.

[@Donna230]

So much fun to watch.

[@mikemike7001]

Just about perfect, front and back.

[@Enigma758]

Not sure why the Atmega328 would have made common cathode more preferable. I thought it could both sink and source a max of 200mA. BTW, these project videos are among my favorites.

[@FranLab]

Because coding pins HIGH would turn them on, which would be more intuitive.

[@Enigma758]

@@FranLab Oh, right. I thought maybe there was something special about the atmega328 itself.

[@askjacob]

@@FranLab that is where setting your own alias in the code saves headaches. LED_On = 0, LED_Off = 1 :D

[@FranLab]

@askjacob Yea, or just flip mentally to LOW is ON - that's what I did anyway.

[@weathermannax416]

How do you work so fast? If I work like that everything will be flying all over the place. It would look like a hurricane has just blown through the shop.

[@richardbrobeck2384]

What A great project Fran !!

[@ReverendFuzzy]

You still need to put a ZIF socket on the UNO board. It'll make it SO much easier to get those Atmega328P chips in and out,

[@FranLab]

Meh.

[@johnwalker861]

Have ever considered trying your hand working in radio Fran , i think the voice that would lend itself well to that medium . Your voice has a relaxing quality to it . I think that it would be worth looking into at least. Take care now !

[@romancharak3675]

Nice implementation, Fran.

Neat! You should consider using an Arduino Nano. Same CPU as on the Uno, and much smaller. You actually would not have had to create a custom board...unless you are trying to pinch pennies. I use copies from China. $2-$3 each. Thanks!

[@FranLab]

The whole idea of making my own board is to eliminate all of the unnecessary, thick, and and power consuming parts of a Dev Board - USB interface, hardware, headers, power supply regulation, LEDs, etc. But you do you.

[@tookitogo]

16:51 “I’ve never destroyed a chip”. No, you’ve never damaged a chip _that you identified as ESD damage._ ESD damage is often incomplete, in that the device isn’t dead, but is compromised, either performing out of spec, or with its lifespan reduced, such that it will fail down the line. But by then you don’t associate it with ESD damage. And above all, damaging ESD is not detectable by the human senses. So we have absolutely no way of knowing that we didn’t cause ESD damage. Consequently, the only thing we can do is take steps to prevent it. Especially in the winter when air is dry. I hate using RSD wristbands, so I am very glad that at work, I have a grounded ESD floor mat. Combined with ESD bench mats and ESD footwear, that means stuff is protected without needing to use the strap.

[@TheWatcherInTheTower]

Nice build!

[@appliedengineering4001]

You should've used a esp8266 like the esp-12 board and have it drive a few 74xx595 chips to control the leds with. That way you could control the LED remotely with your smartphone.

[@FranLab]

The last thing I would want to do is use my phone. So uncool.

[@tookitogo]

@@FranLabHowever, I would recommend using a more modern MCU, simply because the Atmega328 is such an old part that’s crazy expensive for the CPU power it provides, and which was also in very short supply during the component shortage. I also really like the NXP PCA9634 LED driver, which has 97KHz PWM (so totally flicker free when dimmed), controlled via I2C. Then even an MCU with few GPIOs can control tons of LEDs individually.

[@Erwinhooi]

great idea, I would have done this with 555 and 4017 but this is less components!

[@appliedengineering4001]

The problem with the 4017 is that it only turns one LED on at a time.

[@theshowdoctor]

Right angle header would have saved you some time... And kept it flush...

[@CARLiCON]

I was just thinking another way you could program this, is like a construction sign, where state 1 is all LEDs OFF, state 2 is #1 (upper & lower ) ON, state 3 is #1 + #2 (upper & lower) ON, state 4 is #1 + #2 +#3 (upper & lower) ON etc. until state 21 where all LEDs are ON, then goto State 1 & loop. It would use more power, so battery life would be an issue, but it would get brighter progressively which may be more dramatic, just sayin

[@tookitogo]

Since she’s not using any transistors or other drivers for the LEDs, supplying that many LEDs simultaneously off the Atmega’s GPIOs will exceed the Atmega’s maximum current carrying ability. She got away with it during testing, but I wouldn’t run it that way long term.

[@frankowalker4662]

It looks great. I would have stuck the switch to the side of the battery pack.

[@willrobbinson]

would not even bother dropping 1/2 volt off the bats ects

[@greglongenecker1772]

I find your voice has a very calming affect on me : )

[@soufianebellahbib7808]

👍🏼passionately 💚🌴☀️

[@Janokins]

Had to stop myself from analysing the code. It does what it needs to do, so who cares how it's doing it? :D Force of habit I guess. Sign is looking good!

[@KeritechElectronics]

That's a really cute project, talk about excess and over-engineering! Nice wire harness. ESD wise, some parts are pretty susceptible and others not that much. I've never blown a CMOS or a MOSFET, but if possible, I observe precautions, especially with that expensive newfangled electric car charger stuff I work on now. Still wondering why not 4017 though.

[@FranLab]

Just because.

[@6F6G]

4017s would do sequential LEDs quite nicely. The Atmel (well Microchip now) could be programmed to do a lot more.

[@Torby4096]

Cool razzmatazz!

[@wiseoldfool]

You cheated, you used cable ties. I'm sure you've used lacing cord in the past!

[@FranLab]

I honestly considered it.... but then, no.

[@wiseoldfool]

@@FranLab Cable ties are much more practical, but a 70's wiring loom built by a skilled operator is a work of art. The down side was that we often ran signal and power cables in the same bundle. No-one would consider doing that today (I hope).

[@BretFrohwein]

FranLab. Every connection carefully hand-wired for unrivaled dependability and fewer service calls.