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EEVblog Specific / Re: EEVacademy #4 - I2C Bit Banging
« Last post by b_force on Today at 06:39:24 PM »
I still think the pace is to fast, I doubt if non-native speakers can follow it.
Feels like you're on a hurry. The viewer barely has time to think about what you just said.

Didn't enjoy it, sorry.
Watched only a couple of minutes of it.

I have not watched this, but generally speaking,  for a couple of other youtube channels I find the youtube speed  control very useful.  One i play at a faster speed because he has a v.e.r.y s.l.o.w natural speaking cadence with lots of long gaps, speeding up by half or even double speed makes it much more comfortable, one I play slower than normal because the concepts are often hard and she is sometimes just going way too fast for me to keep up, slowing down makes it easier to follow.
The speed control doesn't change the pace.
By that I mean pauses etc that the speaker implements to give the audience time to think about the things just said or to emphasize certain parts.
For that reason you can't expect the audience to do THAT by themselves, simply because they are the ones looking for information.

Second minor thing is that it feels very odd to slow down or speed up.
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There's also the matter of the default non-programmed settings of non-volatile configuration registers (aka 'Fuses').   E.g. many Microchip PICs and (ex-Atmel) AVRs wont run unprogrammed in many typical application circuits because their default clock mode isn't compatible with the clock circuit components present.
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Open Source Hardware / Contact temperature sensor DS18B20
« Last post by yamadanao614 on Today at 06:28:09 PM »


I need a contact temperature sensor to get the temperature of a container. How about ds18b20?

Anything like LM35 which I found from google search gives me ambient temperatures. Can anyone suggest an easy to use contact temperature sensor? Accuracy as high as possible! I am going to use it with an Arduino Due, if that information is relevant.
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Beginners / Re: Profitability of component level repair on electronics?
« Last post by Ian.M on Today at 06:25:45 PM »
As a rough rule of thumb, consumer electronics devices depreciate in value by about 33% per annum (excluding rare and./or collectable items).   It is very difficult to justify the cost of a repair exceeding 50% of the residual or replacement value of an item.  This breaks down at the lower end where the convenience of not having to source an exact replacement or make other changes to use an alternative replacement may persuade the customer to accept a repair quote higher than the replacement cost, but its nearly impossible to make a living doing small repairs at less than $50/item, unless you are very very good at doing them very quickly, have enough demand to keep you busy (but not so much that your turn-around time suffers) and specialise in a limited number of models so you can keep stock of all spares required for same day or while you wait service.

Its *EXTREMELY* difficult to get started as a small business owner in the electronics repair trade in any 1st word country.  The fixed costs and overheads of setting up a business are high, even if you work from home, and unless you are already near-expert in a high value niche market and have a good contact list, you'll face great difficulties growing the business fast enough to break even before you run out of your startup capital.
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Beginners / Re: Mosfet Ohmic Region Control
« Last post by Johnex on Today at 06:20:37 PM »
Thanks for the ideas guys.
Ian, do you have any examples i can take a look at and scale up?
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Noise measurements are difficult with meters that do not have a PC interface or at least logging feature. So it does not work with most handheld meters. Quite often in handheld meters the noise is at or below the resolution limit - for manual reading it is kind of inconvenient if the last digit is constantly changing - this adds quantization effects. Depending on the value read the output may stick to a value or show the 1 digit jumps - both cases hide the true noise.

A 1 ┬ÁV resolution with low noise is rather good for a handheld meter.
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EEVblog Specific / Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Last post by G7PSK on Today at 06:14:04 PM »
Thats the whole point, you do not get out the multimeter until you have confirmed that the circuit is dead and isolated safely by padlocking it off. Risk from using multimeter on the wrong range should then be zero. This is indeed what electrical engineers who work on large circuits such as factories etc are trained to do.

Working in an industrial setting is one thing. But I wasn't thinking of that. I was thinking of working in non-industrial settings like residential buildings and office spaces, HVAC systems and such like. Does your home have multi-padlock safety interlocks? Can you be sure that all the wires in a junction box are on the same breaker? They should be, but there are certain cases in old buildings (and my house) where they aren't.

I think that to a large extent the CAT ratings have been used as a marketing tool by some company's even driven by them.

There are lock out devices for domestic switch boards and offices HVAC etc and should be used especially where there are other people working on the system or where there are people who might turn the power back on when they find the coffee machine or whatever is not working. Lock out devices should be used by more than electricians, I know of a case where a farm worker was cleaning an elevator, he had done all the proper things like turn off the main power switch. Unfortunately for him someone else came into the barn saw the lights were out and went and turned the power back on, this started the elevator and he was pulled in and drawn halfway up before the idiot that turned the power on heard his screams realized what was going on and turned the power off again, when the fire brigade arrived to extricate the man they had to turn the power on and wind the man the rest of the way up the elevator in order to get him out by that time his hand was in a pretty poor state. So any one who is going to do any thing which involves shutting off power needs to be able to make sure the power is not coming back on until they are ready and it is safe.
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Test Equipment / Re: $20 LCR ESR Transistor checker project
« Last post by mauroh on Today at 06:09:29 PM »
I just bought this direct from taobao.  I think it is most suitable for me at this time.  Last I checked, it was not available on ebay or banggood.  They have an adapter that plugs into the 4mm.  The adapter has a ZIF socket and surface mount pad.

Edit:
This unit could run
https://github.com/svn2github/transistortester/tree/master/Software/trunk/mega328_st7565_kit

Is there a "m" version readily available for this kit?  Thanks.

At Banggood, they call it Hiland DIY M12864 Kit
I preferred this version because it has a nice case and it is faster compared to the latest AY-AT
Attached you can find the m-firmware 1.29 compiled for that hardware (8MHz and 16MHz)
I enabled also the servo function that I use frequently

Have a nice day
Mauro
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General Chat / Re: What did you buy today? Post your latest purchase!
« Last post by McBryce on Today at 05:56:13 PM »
Painted it with acrylic blue, now it looks professional  :)

Tektronix would approve :)

McBryce.
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Manufacturing & Assembly / Re: Homemade manual pick and place
« Last post by Kjelt on Today at 05:56:00 PM »
I always use 45 degree needles and hold the pincet under 45 degrees.
That is to have a clear point of view because I place the parts looking under a stereo microscope.
That is the main disadvantag I see from these placers you need a camera and can only see a part of the picture esp. with square ic packages.
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