EEVblog #1244 - Mailbag

[EEVblog]

More Mailbag!



SPOILERS:
Mailbag SPAM!
Arizona
If it smells like chicken, you're holding it wrong.
2:57 https://www.tympan.org Open source hardware audio hearing development system.
11:20 Circuit Scribe conductive ink learning kit https://www.circuitscribe.com/
24:20 Sony RM-440 video editing unit teardown
30:42 Pulse Sensor https://www.pulsesensor.com
31:36 DIY Mouse Kit https://github.com/biomurph/Mouse
32:26 DIY OpenHak open source Fitness tracker https://www.openhak.com
36:34 Faber Castell TR3 scientific calculator and slide rule
42:22 Thermocouple Raspberry Pi Hat http://www.scientificdatasystems.co.uk
46:35 Casio FX-82 Calculator


Ohms Per Square Sheet Resistance video:

Thermocouple Tutorial Video:

[johnlsenchak]

I  don't think  "Fundamental  Friday's " is boring, I wish  you would  do more of them 

[Fungus]

Quite a good slide rule.

Does the middle, slidey part flip over? It looks like it's upside down.

[ggchab]

I  don't think  "Fundamental  Friday's " is boring, I wish  you would  do more of them 

I also like Fundamental Friday's 

[Ibex]

RE: Tympan

Dave,

Click on the three-bar menu icon (hate 'em! ) at the top of the tympan.org page and there are links to some information pages and their forum. Tympan is an open source hearing aid project. From a quick glance at the forum it looks like people are trying to do some interesting things with it.

[Kleinstein]

Getting 7 input channels for the thermo-couples is  likely because there is one channel used for internal purpose like the cold junction or zero correction.

When testing the conductive ink with sharp probes, there are two contributions: one is the thick film part and the other is the spreading resistance around the small contract. To really check the painted resistance it would likely take a 4 wire measurement.

With the calculator it looks like the one digit that sometimes got to bright probably got a problem (e.g. shorted out common pin). This may also effect the keyboard.  There is a visible solder bridge / tin splatter on the board.
I don't think the calculator is genuine Faber Castell, more like an OEM solution. The LEDs look a little like the HP bubble ones.  Some 20-40 mA from 4 coin cells in series sounds like a fail, unless rechargeable. The slight rule is a backup when the batteries run out  .