EEVblog #722 - Mailbag

A monster Mailbag, with extra waffle and advice for youngsters.

SPOILERS:
GPS based Back To The Future speedometer display
Cypress Semiconductor PSoC Bluetooth Low Energy demo kit
PCB Backlit calendar
Geoaching waypoint altitude decoder
How do strain gauges work?
Vintage components from the cold war eastern bloc

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[winstonsmith]

Clean the mat with isopropyl alcohol. Gotta' rub, but it comes off.

Spring loaded USB cables will really launch whatever small device is attached to them when they fail. If they had a _manual_ lock on them, they'd be worth something.

[RaccoonRocket]

Isopropyl alcohol removes sharpie stains.

[Pieh]

24:04 It says "For further specifications apply to the instruction manual for semiconductor strain gauges. The quality of the strain gauges complies with the respective rulings or requirements as sited in the contract."

[SetMyLife]

That "velvet-feel" coating on plastic is total rubbish, from long term perspective. It **decays** into horrible gunk that peels off. Happened to my joystick.

[LazerLord]

Wow, I have one of those Radioshack T-shirts too! I just bought mine at the store before it closed down. I feel like I should save it for posterity, but I just want to wear it around everywhere.

[fredflintstone]

Truer words where never spoken when Dave said it's better if your projects 'don't work'. You learn so much more from your mistakes than you do from your successes. Failures make you dig in and figure out what you did wrong which forces you to have to learn to understand how things work. It's really hard to get this kind of knowledge any other way.
 Regarding free ranging children, my mother would probably have a heart attack if she knew where my sister and I wondered off to as 9-10 year old children back in the days when kids had adventure (60s - 70s)..

[markbell]

Always like that you spend a few extra minutes giving the young folks some advice, and if I may I have a couple of other suggestions for Michael.  Make a trip to thrift stores (Goodwill, Salvation Army, etc.) and you can find radios, video cameras and yes on a lucky day some test equipment.  So for a few buck you can get some stuff to teardown, learn about and start collecting parts to build projects.  Also, if you live in a city with a university they will from time to time have surplus sales, and you can find some amazing items on the cheap.
 
Cheers,
Mark
 
PS: At university auctions items are often sold in lots, but you don’t have to by the whole lot, but can usually get an item or two for a few buck from the lot winner.

[guruaccount]

Dave is really good at encouraging the next generation and teaching them to turn a mistake into a lesson learned :) very nice of you sir -- keep doing the good work!  

[yssing]

11. that is really great :)

When I was a boy I was really in to electronics, made a lot of different setups, but gosh I wish there was, well Internet and you back then :)

I really enjoy the EEV blog.

[AJMansfield]

Use sharpie marker to clean off sharpie marker! It's super simple: take your sharpie, and scribble all over the mark you want to remove, then immediately wipe it off. The solvent in the sharpie marker will dissolve the sharpie on the object and allow it to be removed, as long as you wipe it off before it evaporates again.

[martinda]

There are two strain guages supplied to both go in the bridge. 
one under compression and one under tension as they are squeezed and pulled when attached top and bottom a sort of push pull in the bridge 

[moldingpro]

That texture is TPE (ThermoPlastic Elastomer).  It is over-molded on the exterior of a stronger plastic (usually) to create a comfortable "feel" for the consumer.

[rkupka]

LOL. First time I heard you got something from Slovakia :)
So fun to hear people from abroad how they break their tongues on our cryptic slavic language.

[cemx]

At 7:52 - Dave - I picked up the Radio Shack T-Shirt on my very last trip to the local store for some bankruptcy bargain hunting.  It was interesting as the store was full of people who grew up on RS and were collectively reminiscing about the "good old times".  I saw the shirt and knew you had to have one!  

[Reality]

24:03
 "Other tech specs you can find in the service manual for semiconductor strain gates."
"Semiconductor strain gates matches working conditions described in a law"
Something like that)

[Aengus]

That open wound cap reminded me of my xmas decorations as a kid. My Dad work in the vacuum metallising & slitting room at S.T.C. (Standard Telephone & Cables) in Paignton, Devon in the 1970's making caps just like that. I used to get rolls & rolls of that stuff & it got spread around everywhere at xmas!

[rbmwiv]

On the velvet feel I have seen it done with “soft touch paint”. BMW uses that in their interior parts. One of my friends use to be the technical supervisor at one of the supply plants in Spartanburg SC. His facility made dashes and center consoles for the Z3’s.

[mopar]

Dave, if you are very careful a little bit of paint thinner on a cotton swab will remove that permanent ink from your ESD mat. Great video too, thanks!

[MyCrazyGarage]

Does ANYONE know how to get this BTTF Speedo? Ive been trying since 2009 to buy it from their site(s).
The Schematics and Gerbers arent avaiable on their blog and theres no shop to buy it from.

[Murphistic]

It was good to see how much fun Dave had with old Tesla components :) . I also have a bunch of them, mainly got from an old Tesla television set (black and white, no remote control, cca 70's vintage). Maybe, it was a bit mistake to destroy it, but it was not working.