EEVblog #72 - Let's Design a Product

In this supersized lecture length episode, Dave foolishly attempts to explain how to design an example product (the uCurrent) from start to finish.

The Full Article:
http://www.alternatezone.com/electronics/ucurrent/uCurrentArticle.pdf

See also:
http://www.alternatezone.com/electronics/ucurrent/

Category:

Science & Technology

Tags:

• electronic
• engineering
• product
• design
• lecture
• tutorial
• how
• to
• multimeter
• pcb
• enclosure
• battery
• circuit

[BitEntropy]

Is there a specific reason why the Off position is on the bottom rather than the middle? The normal operation of it would just be turning it off and on, and occasionally using the battery check. In the current layout, any time you want to turn it on or off you are moving the slide two positions (and putting more wear on the switch) and powering the LED, even if temporarily.

[EEVblog]

@BitEntropy No, the LED does not switch on if you move the switch quickly enough, a nice side benefit. It's easier to move the switch all the way to one side than centre it, so it's easier to switch it off.

[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!

[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.

[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

[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?

[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