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GrizzledGeek
(@grizzledgeek)
New Member
Joined: 2 weeks ago
Posts: 3
2020-09-09 10:28 pm  

My name is Michael.  I’m a retired Electrical Engineer who recently got interested in a project that involves small sensors interfaced to a microcontroller.  I was delighted to discover the Arduino programming environment and the wonderful (and cheap!) device ecosystem that surrounds it.  They’re a perfect re-entry point for me after several years of retirement.

Just as a point of reference – the first ICs I designed with (before going on to design them myself) were the uA741 and TI 7400-series TTL.  And the first programming languages I learned were Fortran IV and IBM 360 assembler [when the 360 shipped with nothing *but* an assembler, not even an operating system!].  It’s been a while … I’m pretty sure that the ATmega328 is more powerful than that mainframe was!

So I’m looking forward to interesting discussions on the Forum as I get immersed in this wonderfully accessible new microcontroller world.  Right now I’m trying to make an MPR121 capacitance sensor (on an Adafruit breakout board) work reliably.  The Arduino library that Adafruit supplies is a useful starting point, but the defaults need tweaking, and the automatic baseline tracking is a nightmare!  

The issue du jour is that when I read back the on-chip registers (via I2C) I don’t always get what I wrote.  Anybody out there with experience on this gadget?


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Doug75
(@doug75)
New Member
Joined: 1 week ago
Posts: 1
2020-09-12 8:12 pm  

Thanks for being on your forum.

I'm a Newbie and I have always loved Electronics.

I learned about this site on youtube, watching videos from time to time.This site is very informative and the Owner is very impressive and well informed.

I'll try to learn as much as possible and also offer information if and when possible.

Regards,

Doug75

 

 


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DroneBot Workshop
(@dronebot-workshop)
Workshop Guru Admin
Joined: 1 year ago
Posts: 570
2020-09-12 10:51 pm  
Posted by: @grizzledgeek

Just as a point of reference – the first ICs I designed with (before going on to design them myself) were the uA741 and TI 7400-series TTL.  And the first programming languages I learned were Fortran IV and IBM 360 assembler [when the 360 shipped with nothing *but* an assembler, not even an operating system!].  It’s been a while … I’m pretty sure that the ATmega328 is more powerful than that mainframe was!

It's amazing how things progress. I also started with 7400-series IC's and 741 & 747 op-amps, and still use 555 timers!

You don't even need to look back that far to see how things have progressed.  

In the mid-1990s I worked as a systems analyst for the Alberta Government. The data center where I worked in Edmonton was supposed to be the third-largest in Canada at the time.  The "size" of a data center was measured by the amount of "DASD Storage" it had.

"DASD" was a "Direct Access Storage Device", a large unit with a very large hard disk in it. Each DASD unit stored 7GB, and we had them mounted in DASD boxes which held four units, for a total of 28GB. In the mid-1990s 28GB was a lot of storage.

Our data center had a football field-sized room with nothing but row upon row of these boxes, qualifying us as being the 3rd largest in Canada.

Flash forward to today - one of my computers, the Mac Mini that I produce the videos on, has 52 TB of external storage, which I am sure is much more than that entire data center had back then. And it's all sitting on one small computer table!

In a few years, I'll probably be able to buy a 64TB microSD card!

Welcome to the forum, both of you.

😎

Bill

"Never trust a computer you can’t throw out a window." — Steve Wozniak


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codecage
(@codecage)
Member Admin
Joined: 1 year ago
Posts: 724
2020-09-13 12:10 pm  

And even more amazing, is the price drop!  In about the mid 80's the first 2MB memory board I ever saw, on a S-100 buss board, was 6995 [guess where the decimal point was located...if you guessed after the five you are correct!].  I just recently purchased a 128GB microSD card from Amazon for 1999, and here the decimal point was after the first nine.  Using the 80s price per byte that SD card is worth somewhere around $447,680.000.00 as compared to that S-100 2MB memory card. And the SD card size is close to that of the fingernail on my pinky finger! And for those not familiar with the S-100 buss those cards were about 10 x 5.25 inches.

Here is a photo of my first 1K (yes, 1024 bytes) S-100 static RAM board.  And it still works!

1K Static Ram S 100
This post was modified 7 days ago by codecage

SteveG


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DroneBot Workshop
(@dronebot-workshop)
Workshop Guru Admin
Joined: 1 year ago
Posts: 570
2020-09-13 3:41 pm  
Posted by: @codecage

Here is a photo of my first 1K (yes, 1024 bytes) S-100 static RAM board.  And it still works!

You mean you still have an S-100 bus computer to test it with Steve?  Don't tell me you actually own an Altair?

🙂

Yes, the price drop is crazy. I remember when a vendor came into our office and was telling us that one gigabyte hard disks would be available soon for under a thousand dollars. And I was thrilled, the thought that one day I might actually own a drive that large really got me excited (which says a lot about me if hard disks get me excited, but that's another story).

The last video I uploaded to YouTube was over 12 gigabytes, so it wouldn't have even fit on that hard disk.  And BTW, that 1000 dollar wonder was a 5 1/4 inch, full-height hard drive.

I also remember servicing communications controllers that used external "Winchester Disks", these were hard drives with a single platter about the size of a very large pizza.  They held a whopping 5 megabytes, and they were belt-driven, and occaasionally you had to change the platter (they were also very heavy) so I always had a spare with me if I went on a service call.  I have no idea what those drives cost, but I'm sure their price-per-byte in todays dollars would be extraordinary!

😎

Bill

 

"Never trust a computer you can’t throw out a window." — Steve Wozniak


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codecage
(@codecage)
Member Admin
Joined: 1 year ago
Posts: 724
2020-09-13 8:48 pm  

@dronebot-workshop

Yes, an Altair that is outfitted with all the S-100 cards that make it a clone of a Processor Technology Sol 20.  However it does have a problem at the moment that I have not tracked down yet that makes it not work quite right.

I also have an IMSAI with a 4MZ Z80 that runs a multi-user UNIX OS look alike called Cromix, from Cromemco. It is working so I have been using it to try to isolate the issue in the Altair. By the way, the Cromix/IMSAI unit has a whopping 10MB ST-506 hard drive attached to it!  😀 

And the company I was working for back in the mid 80s was attaching a CDC SCSI hard drive (forget the name it used) to our bigger business systems that was 96MB.  It fit into one of the deeper 19 inch racks and weighted a ton (not really, but it took at least two people to move it). The drive had 80MB fixed and 16MB on a removable cartridge.  Those platters were at least 14 inches in diameter if I remember correctly.

And I have a story about a very interesting service call I had to troubleshoot a problem with one of those 96MB hard drives, but we'll leave that for another day.

This post was modified 6 days ago by codecage

SteveG


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GrizzledGeek
(@grizzledgeek)
New Member
Joined: 2 weeks ago
Posts: 3
2020-09-15 9:33 pm  

LOL! 

Everybody knows about Moore's Law, of course -- compared to when I was first designing integrated circuits in 1971, design rules have shrunk about 10,000 times, resulting in an increase of circuit density per square cm of about 10-100 million.  Along with a corresponding reduction in power per operation and $ per logic element.  But you guys are pointing out that the density (and cost, and power, and *weight*) of magnetic storage has decreased about as much, on a mostly independent technology trajectory.

All of it is a testament to the power of several thousand engineers beavering away day by day, mostly generating incremental improvements (along with the occasional breakthrough) -- all of it accumulating to produce an exponential technology evolution that's lasted over 50 years so far!

And now we get to enjoy all that progress, with gigaflops and terabytes at our fingertips for little more than pocket change.  What a great time to be doing electronics!


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robotBuilder
(@robotbuilder)
Reputable Member
Joined: 1 year ago
Posts: 493
2020-09-16 12:05 am  

And now we get to enjoy all that progress, with gigaflops and terabytes at our fingertips for little more than pocket change.  What a great time to be doing electronics!

Hardware has become more modular without the need to understand it much at the discrete component level as has the software to use it with its libraries.

It is also a great time to be doing software!

Welcome @grizzledgeek I assume the forum title reflects your age?  Seems like there are plenty of oldies joining the forum and posting.

 

 


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GrizzledGeek
(@grizzledgeek)
New Member
Joined: 2 weeks ago
Posts: 3
2020-09-16 7:14 pm  

Yup -- another oldie.  Fact is that the last 15 years of my working career were spent at a computer, running circuit simulation, CAD and analysis software.  The high points were the occasional chances to turn a knob on a spectrum analyzer or oscilloscope to look at a real live signal. 

Now that I'm retired, the availability of Arduino and its relatives has re-awakened the pleasure of actual hands-on work.  Ah, the smell of a hot soldering iron!


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