EEVblog #1254 - Mailbag

[EEVblog]

SPOILERS:
USB Stick Teardown
1:37 $2 Multimeter Teardown
4:21 Dick Smith Funway Into Electronics Book
Dick Smith Talk:
Tandy 200-in-1:
Dick's Youtube Channel:
9:58 Electronic Hanukiah & XMAS Tree LED snowflake
https://amzn.to/2J5x0V9
https://www.tindie.com/stores/djacobow/
17:47 USB CAN Bus Interface https://www.medo64.com/cananka/
19:49 LORAwan sensor node https://github.com/itofficeeu/ito-sensor-node
24:42 Electronoobs DIY T12 Soldering iron
https://www.youtube.com/electronoobs
https://electronoobs.io/
https://electronoobs.com/
35:43 Acer C20 Mini DLP Pico Projector Teardown

[maginnovision]

I love the idea of a menorah on a christmas tree. 

[wilfred]

What is the board to board connector @42:25 called?

Does anyone not Aussie understand what "second suck of the sav" means? BTW it is colloquially more common to say "Fair suck of the sav".  And although I've said it I don't actually know what the origin is. Other than "sav" is short for saveloy.

How much extra does all that routing of the snowflake PCB cost? It must tie up the machine for a long time.

The DLP projectors had a rotating colour wheel to provide RGB light to the DLP mirrors so that complex optical arangement and the disco filter would have to duplicate that function.

The projector really should have been a separate teardown.

[jhpadjustable]

What is the board to board connector @42:25 called?

Looks like a plain but thin mezzanine connector to me. Hirose specializes in those down to 0.5mm mating heights, if not smaller. Their FC range would be a good place to start browsing.

The DLP projectors had a rotating colour wheel to provide RGB light to the DLP mirrors so that complex optical arangement and the disco filter would have to duplicate that function.

The LED packages together contain one die for each primary. You can see two dice in the first LED to come out, in the right-hand package near 43:21. One die is a deep red, the other is a fairly normal semiconductor metal color. Sometimes a diffuser is just a diffuser.

[johnlsenchak]

That's  how I got  started in  electronics  with those Radio  Shack  150  in  1   kits in 1980  , spent  hours  on it. 


Where did you  get  that  connector  adapter  set?  that's  pretty  wild  you  have  one  for  every  DC plug

[wilfred]

What is the board to board connector @42:25 called?

Looks like a plain but thin mezzanine connector to me. Hirose specializes in those down to 0.5mm mating heights, if not smaller. Their FC range would be a good place to start browsing.

The DLP projectors had a rotating colour wheel to provide RGB light to the DLP mirrors so that complex optical arangement and the disco filter would have to duplicate that function.

The LED packages together contain one die for each primary. You can see two dice in the first LED to come out, in the right-hand package near 43:21. One die is a deep red, the other is a fairly normal semiconductor metal color. Sometimes a diffuser is just a diffuser.

Where does green and blue come from then? I saw the red you mentioned and maybe it is easier to split just two colours in such a confined space. I also saw what looked like 94V on the LED cable. Would that be to reduce the current handling of the cable?

[jhpadjustable]

Where does green and blue come from then?

The other two dice. Most LEDs are a fairly normal semiconductor metal color when off. The red filter/phosphor is probably there to improve that LED's chromaticity. Maybe the red dice they use have an especially wide emissions band. Anyway, the other die in that package is green or blue, and the second package contains whichever primary's left.

I also saw what looked like 94V on the LED cable. Would that be to reduce the current handling of the cable?

No, that's a UL flammability standard and only part of a rating.

[EEVblog]

Where did you  get  that  connector  adapter  set?  that's  pretty  wild  you  have  one  for  every  DC plug

Somewhere on ebay

[jonovid]

48:10 video projector teardown
looks like the DMD chip somehow get cooked in their cells by heat damage? so a static image is somehow  baked-in to the chip display.

[128ITSH]

I apparently have the "original" cheap multimeter that is sold at 2$ now.

It is the Hongda DT-380D (probably chinese) that my dad bought 20-15 years ago, and was around 10-25$ to my guess.
As you can see in the pictures, the outside looks very similar to the one in the video, but the PCB is completely different.

Here's a list the differences between mine and the one Dave tore down in the video:
- It has no SMD components (Except the chip, which looks similar).
- The contacts are going right through the PCB, and that's better than those in the video. (except that the COM contact is too wide so when you connect a probe it can come loose or not make a good connection   ).
- There is a 200mA fuse on board, but not a 10A one. There is an additional PTC fuse for something though.
- There is a trimmer for some calibration.
- More passives than the one in the video
- The spring on the top-right side connects ground to a shielding plate in the back cover.
- Square wave output function. I have never actually used it but checked it on an oscilloscope and it outputs some kHz, can't recall what voltage.

Unfortunately this is the meter that I have to use every day , but fortunately I'm only an hobbyist and it does the job at reading low voltage and resistance and checking for continuity. Can also read mains voltage without blowing up as long as it's in the  600VAC range, I never tried to see if it has input protection in case it is on a wrong range. Anyway I hope to buy a new, better one in the next year.

Just wanted to share this a-little-old piece of hardware, which has at least visually inspired the outside look of these crappy new 2$ multimeters.

[ali_asadzadeh]

Do we have cheap and affordable DLP modules? any thing in china? or any one Beside TI are making them?

[SilverSolder]

I apparently have the "original" cheap multimeter that is sold at 2$ now.

[...]

Just wanted to share this a-little-old piece of hardware, which has at least visually inspired the outside look of these crappy new 2$ multimeters.

You have to be impressed with the engineers that manage to get a relatively complex product to even work at all, at these price points. 

I recall tracing out the circuit diagram of a 5V switch mode wall charger...  that used only one single transistor to perform both switch mode chopping and voltage regulation of the output.  Genius!

[SilverSolder]

Wonder how they got the DLP projector to work without a rotating colour wheel?

[Fungus]

Wonder how they got the DLP projector to work without a rotating colour wheel?

RGB LEDs? 

[jonovid]

4:50
Dave, eevblog should have your own beginners electronics, fun way type or electronics for kids books.
for electronics in schools. esc..

2:19
where would Stock Electronic Image FAILS be without this multimeter 
besides what other multimeter doubles as a cheap utility box enclosure.

[djacobow]

I love the idea of a menorah on a christmas tree. 

So, I guess it is funny. But there are a lot of mixed families, and even among all-Jewish households, there is definitely tree-envy. There certainly was in mine!

However, just for the record, those menorahs will stand up on their own and can be used just fine without a Christmas tree.

Full Disclosure: I am "South Berkeley Electronics"

[djacobow]

Dave,

Thanks for opening up my holiday thingies on mailbag and for the good comments.

Didn't mean to "jam" you with weird unfamiliar stuff. A Hanukkah menorah is a special candelabra used to celebrate the festival of Hanukkah, which is a minor Jewish holiday that occurs around Christmas time. A new candle is lit each night for eight nights. That's really all there is to it. The "on" button goes directly to reset, but you can "long-press" the night button to get into some silly modes that have nothing to do with any holidays. :-) There was no reason for me to assume you would be familiar with Hanukkah, so I apologize.

As for the snowflake, it has an IR detector for the remote, an ambient light sensor for dimming as you surmised, and a microphone for going into sound-flash mode. You can also do various long and longer presses of the buttons to adjust pattern, variation, speed, etc. I overloaded the heck out of those buttons, but my intention was that it would be just a sort of silly toy / puzzle / curiosity thing.

Best,
djacobow
a.k.a. "South Berkeley Electronics"

[SilverSolder]

Wonder how they got the DLP projector to work without a rotating colour wheel?

RGB LEDs? 

 

[Quarlo Klobrigney]

Oy!  I don't think a menorah goes on a Christmas tree.
Que the sound of garments being rended.

Sorry Dave..

[Ketturi]

I apparently have the "original" cheap multimeter that is sold at 2$ now.

It is the Hongda DT-380D (probably chinese) that my dad bought 20-15 years ago, and was around 10-25$ to my guess.
As you can see in the pictures, the outside looks very similar to the one in the video, but the PCB is completely different.

...

Just wanted to share this a-little-old piece of hardware, which has at least visually inspired the outside look of these crappy new 2$ multimeters.

Well in that case, I do apparently have the grandfather of these "DT-830" multimeters  . All through-hole and none of those newfangled CAT ratings or protected input jacks.

[maginnovision]

I love the idea of a menorah on a christmas tree. 

So, I guess it is funny. But there are a lot of mixed families, and even among all-Jewish households, there is definitely tree-envy. There certainly was in mine!

However, just for the record, those menorahs will stand up on their own and can be used just fine without a Christmas tree.

Full Disclosure: I am "South Berkeley Electronics"

My wife's family is Jewish but also has a tree for Christmas. It's really just the idea of the menorah on the tree that makes me laugh.