EEVblog #72 - Let's Design a Product

[fingerboy18]

I'm incredibly impressed. These should be selling by the truckload. It's elegant, compact, functional, ergonomic, producible, and economical! You just proved that simple is better. Your attention to detail shows the importance of creative skills that many engineers lack. Most engineers likely forget about how the product feels when they get too caught up in the circuit. Yeah, their circuit might be good, but it looks and feels like garbage.

[JaffaMicroBrain]

What is a mouldy meter?

[aptsys]

I would always limit the bandwidth with a feedback capacitor on something like this.

[vladimirFNX]

Awesome!! You taught me more in 51 min than my teachers in a year!

One unrelated question, What components should I use to control 30A loads, it's for an electric oven, Could TRIACs do the trick?

Anyway thankyou man, great work!

[kordunasNo1]

nice, love how you used PCB for the face of the product

[CDMCSD2]

I have a question, on the PCB top side, how did you draw those rectangles with transparent labels on them? ALso, did you use Altium DXP?

Thanks

[supremeG1000]

if anone here wants new internet, DO NOT GET FCKING TPG

one of th worst providers ever, the fucking speed is 1.5mbps

[Saakian1994]

lol



[mashersmasher]

and here i thought auzzies just drove around in the desert hording gasoline. Hurray for EEVblog, the humungus of the electronic wasteland :P

[artifactingreality]

Nice product... but why don't the multimeter companies build that functionality straight into the meter? Forgive me if there is a really obvious reason I'm missing.

[errold32]

EE Student

Fantastic work, I enjoyed hearing about the design process. That red PCB looks so good, I never suspected that was what it was.

[TelevisionMagForum]

Excellent as always Dave.

Any chance of a few close up stills being onscreen for a few seconds in this type of video?

Never would have crossed my mind to make the pcb the front panel. Great stuff!

[jkenny1]

Great video! I'm a second year EE student and we just never learn these sort of little tricks of the trade, I found your use of an op amp voltage follower to split your voltage supply very interesting and may come in handy for me sometime.

[mdmde]

Very elegant & useful design Dave. The 200mA fuses in multimeters are always blowing, among other problems that you addressed. Your product looks good, too.

[vk3ye]

@gameboygenius - If you were using AAs your idea of using 3 would allow use of NiCads/NiMHs (whereas a 2 battery design wouldn't (only 2.4v). I like this versatility.

But rechargeables aren't ideal for an occasionally used low-drain piece of test equipment due to internal discharge, so accommodating rechargeables isn't as big an issue.

Although generally I like using an even number of AAs as they come in 2s and you don't have one left over when you need to change them.

[eyeeye1]

Dave, I'm four week's into a AC/DC Fundamentals class,and your natural way of explaining thing's make it very easy to understand and a pure joy to watch.Thank you.

.

[xspoonedx]

Fantastic work Dave, really interesting to see how it all fits together! Especially useful for students such as myself. You often mention how important the PCB layout is and as such I would like to echo oehrlein49's request for a PCB design blog.

I do have one question though; why didn't you just flip the LED around in the circuit to give you low voltage detection?

[EEVblog]

@xspoonedx

Interesting question.

If you have the LED operate the other way around and have it only come on when the battery is low, then if you go to turn the unit on and the battery is completely flat, then it won't come on and you'll think your product can be used. So in this case (with no power LED), it's better to have it the other way around so you can check the battery is OK before you use it. So you could say it's more important to know that battery is OK, than know if it's flat!

[MonkeyFCoconut]

I watched this over the last two nights with my 4 year old inventor son, for his bedtime story :) To his credit he was really listening for the first 10 minutes of each 25 minute night... and he loves the way you say "banana" Dave. I really enjoyed the video and all of the information. Thanks for taking the time to put it together!

[oehrlein49]

love the idea of using the PCB as the front panel! great idea!

A few questions:

1) Who made the PCBs? I'm looking for a board shop that does red boards.

2) Is there a special/low cost deal for Altium designer? How much do you pay for a license? Isn't it prohibitively expensive for small companies?

Other comments:

I would love for you to do a video on PCB layout. Not for complete beginners, but maybe just some intermediate level tips.

Cheers,

Matt

[EEVblog]

@oehrlein49

I use PCBcart, cheap and plenty of options.

No special deals for Altium Designer unless you are a student. Otherwise it's $3900/year or $5K outright for the PCB version. That's less than half the price it used to be.

[Gameboygenius]

A subtle little thing... If I were to use AA/AAA's for this project I might've used three batteries instead of two, to avoid wasting battery power and having to switch batteries more often than needed. (2.6V/2=1.3V/cell vs 2.6V/2=0.87V/cell) Of course you'd have to consider battery impedance and such.

Which brings me to something I'd like you to speak about when seeing this: The black art of bypass capacitors, which would probably deserve an episode on its own merits.

[rek636]

good stuff.

Ill finish it tomorrow, now time for sleep

[marcelkanter]

@ 30:50 How about compensating the output offset due to the multimeter by connecting the upper connection of the 99k res. to the "real" output instead of to the output of the opamp? With this config, the opamp compensates the drop over the output protection resistor too...

[marcelkanter]

...in case of an short circuit of the output terminals it would lead to maximum output current, but the most opamps are output short circuit protected...

[dc100GHz]

HI Dave, excellent video I really enjoyed it from start to finish. But one thing I didn't pick up how did you design the PCB? What software did you use, and did you order ready made PCBs or make them yourself?

[EEVblog]

@dc100GHz

I used Altium Designer and got the boards made by PCBcart. Next to impossible to make your own silkscreened and solder masked boards.

[nickmctrick]

Thank you for such a wonderful tutorial on this subject.

[msichal]

OMG, I'm impresssed, 50 mins of a great material, using PCB as the front panel - great idea!

[Twistx77]

Great video! I really enjoyed, just one thing what about regulations to sell it internationally?

[ntjbjhq]

Your best video yet Dave, length was perfect for such a complex topic. Please keep up the longer format from time to time, don't wait another year for one!

Cheers!

[First2ner]

yep, good design, from start to end, I like how you used PCB as front panel

[killerman4ever]

@EEVBlog Aha, youtube is getting buggy lately.

[Afrotechmods]

Doc Brown would be proud!

[GeorgeGraves]

I'm 3 minuets into this things and I can already tell you've knocked this one out of the ball park. I'm going to grab a beer and some popcorn and enjoy my next hour of engineering bliss.

Cheers.

George Graves

[EEVblog]

@GeorgeGraves

Thanks.

Hey, your comment got posted 3 times and got flagged as spam by Youtube! Yet another youtube new comment system screw-up?

[GeorgeGraves]

@EEVblog Surely user error. ;)

[killerman4ever]

Still progressing on my iPod :(.

[chromebeats]

wow

[pjpeter99]

Excellent!

[nlhans1990]

That was a really interesting and nice video. Don't hold back on these please, I loved it. Goes to show that getting exactly the right components (not overkill or underestimated) takes so much more than actually thinking of the circuit and simulating/testing it. Thanks for the tips!

[amilliondead]

Wow. I am so happy I found your vidcast Dave. Brilliant stuff.

[hla27b]

Wow Dave

51 minutes and you didn't waste a second. I couldn't fill 51 minutes in front of the camera.

One question, how long does the battery last? Say if you forget it switched on?

[EEVblog]

@hla27b

Yeah, in all that ranting I forgot to mention the battery life!

More than 200 hours.

I determined that it wasn't worthwhile to add an auto-off function to this first version, as that would have required an intelligent device to do it properly.

[TheWelly888]

Dave Jones, best broadcast out of Australia since "Neighbours"! And a LOT better too!

[valordk]

51 minutes of the best product/process presentation I've ever seen! thanks for sharing.

[killerman4ever]

EEVblog72-1280x720.mp4 ?

Thats new.

[EEVblog]

@killerman4ever

Bloody youtube privacy bug again! No one was supposed to see the video before it finished processing and I had added the detail!