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Author Topic: Most unexpected places to find a Atmel microprocessor...  (Read 2493 times)
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Peoples Republic of Cantabrigia
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For work, I do a lot of teardowns... usually I find PICs in just about everything related to heating and cooling systems though the occasional freescale processor may slip in. Almost never an Atmel though. You can imagine my surprise when I recently had to take apart my Kenmore-branded vacuum to make a repair for a IMO design defect (high resistance connection = heat = melted plastic + charring).

Starting the show with the underside of the PCB inside the handle of the "intuition" canister vacuum cleaner, about 2 years old. It can be found inside the handle, where the user can set speeds, options, etc. Lots of SMD components and a ATTiny 8 is running the show in there. The actual UI (buttons, LEDs, etc. are in a separate housing assembly.



... and now for the other side .... Presumably, the epoxy / ceramic encapsulated SIP set in goo is the power supply.



Here is a innovative way to cool the variable-speed power supply (a Triac)... Note the use of a heat sink that also acts as a mounting point for the board and for whom one surface makes up part of the "inner tube wall". Presumably this approach was less expensive than using a multiple-tap PSC motor, a couple of relays, and more wires/terminals from the canister to the handle.



This BTA08 Triac evidently gets quite hot, note the charring on the white wire that had rotated backwards. This wire is presumably the neutral coming up from the canister via the hose. I found that the two clips that were supposed to hold the tube had both failed so I taped it in place instead.



Here is a picture of one of two wire terminals I replaced. This one is the female half - the male is in the tube extension thingie between the hose and the sweeper on the floor. The male version is set in a hard resin, while this female end is set in a softer SBR-like material. As you can see, there appeared to have been a high-resistance connection in there, leading to charring. Needless to say, I am not impressed with this design.



My guess is that the soft SBR allowed one of the terminals inside the rubber to become dislodged or pushed out of the way. Once the contact area becomes smaller, high temperatures due to lower contact area and/or arcing do the rest to kill the plugs. Because the Triac and the plug come as one assembly, I got to spend $53 over at Sears just for the parts. On a $400 vacuum cleaner.

My other Kenmore vacuum cleaner is finally biting the dust after 10+ years of service. Its plastic housing is literally being worn through by the wheels mounted on it. I doubt that this "Intuition" whose handle I showed you will last as long.

What interesting / unexpected places have you found Atmel microprocessors?
« Last Edit: August 14, 2012, 07:47:20 am by Constantin » Logged

Dubai, UAE
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Hi,
   There is a similar thread in Bar Sport - http://arduino.cc/forum/index.php/topic,111641.0.html

It doesn't see much action, maybe yours will see more in this section.

Duane B

rcarduino.blogspot.com
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Peoples Republic of Cantabrigia
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Who knows how many other crazies open their devices and actually look at the microprocessors running them...  smiley-lol

I was simply surprised that a general purpose CPU would be running a vacuum cleaner. Granted, it's a small one... and minimizing the number of wires running to and from the canister presumably saves a lot of money given where copper prices are now. Plus, you get to sell "variable speed" air flow to consumers for a premium instead of relying on bypass air rings as in the past to modulate the suction at the ground level.

Thankfully, I have neither the means, motivation, or time to try to hack into this CPU.  smiley
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Thankfully, I have neither the means, motivation, or time to try to hack into this CPU.  smiley

And so the potential army of self-propelled, RC canister vacuum cleaners has been averted meaning the small dogs and cats of the world can sleep safely tonight... smiley-wink
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I've seen one on the back of hard drives.
AT27C256R
apparently, it's just a eprom
I also found one on a really old apple laptop mobo. I don't quite remember what specific chip it is, but it was definitely a microcontroller (I searched it up when i found it)
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Peoples Republic of Cantabrigia
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And so the potential army of self-propelled, RC canister vacuum cleaners has been averted meaning the small dogs and cats of the world can sleep safely tonight... smiley-wink

 smiley-eek-blue smiley-mr-green smiley-eek smiley .... umm my thoughts precisely.
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I also found one on a really old apple laptop mobo. I don't quite remember what specific chip it is, but it was definitely a microcontroller (I searched it up when i found it)

I have seen simple circuits for power supply control in several appliances. A drop-cap power supply brings in the power, a small MCU or switch then powers a triac that then allows the main PSU to turn on as needed while using minimal standby while the appliance is in "deep sleep". Even works with linear power supplies using fat transformers. A nifty way to minimize standby power requirements.
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