Wednesday, February 11, 2015

Lab 4

In Lab 4 you will complete the layout of several independent circuits. We will get these designs fabricated, and you will assemble and test the circuits in Lab 6. There are three circuits that you will lay out for this lab:
  1. The surface-mount LED flasher that you completed as part of DipTrace Tutorial Day. 
  2. A simple microcontroller board. One possibility is a copy of the Arduino Micro, and you can find the schematic on their website. Other possibilities can be discussed with the staff.
  3. An analog drum voice. Schematics will be provided in class.
To complete this assignment, you must deliver the following documentation:
  1. Simulations of the first and third circuits in LTSpice
  2. A complete schematic for each circuit
  3. A complete bill of materials for all the parts (including source, stock number, and cost)
  4. A complete layout in DipTrace (suitable for fabrication)
Lab 4 is due Monday, February 23.

Monday, February 9, 2015

Drum Machine Documentaries

Homework: watch the following videos about the Roland TR-808 drum machine.

First up is a short trailer for an upcoming documentary called "808" (premiering at SXSW).



Second is an excerpt from the  BBC documentary "The Shape of Things that Hum".



If you have the time (82 minutes), the full documentary is on YouTube. It discusses a number of important electronic instruments, including the MiniMoog synthesizer, the vocoder, the Yamaha DX7, the CMI Farilight, the Simmons drum machine, the Roland TB-303 bass synthesizer, the Roland TR-808 drum machine, and the Akai Sampler.

Saturday, February 7, 2015

DipTrace Tutorial Day

The class assignment for Monday (February 9) is to complete two tutorial projects in DipTrace. Before class on Monday, please complete the following homework:
  1. Get DipTrace installed on your laptop. See the Olin instructions here.
  2. Get the DipTrace Tutorial PDF file.
In class on Monday, we will complete the following projects:
  1. Complete the schematic and layout tutorial, pages 1 through 79.
  2. Complete a second layout of the "Astable Flip Flop" using only surface-mount parts.
    • Transistors: ON Semiconductor MMBT3904LT1G (SOT23 package)
    • Capacitors: 33uF  TDK Corp C3216X5R1C336M160AB (1206 package)
    • LEDs: Lite-On LTST-C170GKT (0805 package)
    • Resistors R2 and R3: 680 ohms (0805 package)
    • Resistors R1 and R4: 34 kilohms (0805 package)
    • 9V battery connector (use same through-hole connector)
Minimize the size of your PCB layout to save space. Save your second layout in a safe place when you are finished (we will get these designs fabricated as part of Lab 4).

After class on Monday, you may want to watch some of the (advanced) Video Guided Tour (should take less than 30 minutes). Make note of any jargon or concepts that you don't understand.

One additional project that we might get started, time permitting, is the layout of a simple microcontroller.  This design is based on the Arduino Micro, and you can find the schematic on their website.


Thursday, February 5, 2015

Lab 3

Reverse Engineering. Take apart and fully document a piece of commercial electronics (provided). Assemble a complete documentation package describing the circuit, components, and behavior of the object. Deliverables (as a web page):
  • Basic test results showing behavior
  • Block diagram of system
  • Bill of materials of all parts
  • Complete schematic of circuit
Document package is due February 12.

Monday, January 26, 2015

Lab 2

Commercial Electronics Autopsy: Take apart a piece of commercial electronics (provided). Take pictures, study construction techniques, draw a block diagram, write a bill of materials of major parts (top ten), and find some data sheets, but don't draw a schematic. Make a list of the major components; the main integrated circuits are important, of course, but don't overlook interesting examples of passive components, sensors, connectors, switches (and other controls), internal cable assemblies, heat sinks, mechanical elements, etc. Deliverables (as a web page):
  • Link to service manual (if found)
  • Basic test results showing operation (or non-operation)
  • Pictures of the disassembly and the insides
  • Block diagram of the system
  • Bill of materials of ten major parts, with date codes and datasheets
  • Discussion of the mechanical design, including functional and decorative elements
  • Short presentation for informal show-and-tell session
If your item has an FCC ID code on it, be sure to check out if any of the FCC filings are public at http://transition.fcc.gov/oet/ea/fccid/.
Extra credit for salvaging and reusing some interesting part from your autopsy (for example: motors, sensors, LEDs, switches, fans, etc.).

Schematics Lecture Notes

Here are the lecture notes for today's discussion on schematics and bills of materials.

Lab 1

Build a battery-powered circuit that flashes an LED.

That's the whole lab assignment. It's up to you to design a schematic, find parts, choose a construction technique, and make sure the customer (your professor) is satisfied. Feel free to ask questions, but you must demonstrate a working circuit by the end of class today.

Difficulty setting:

Sunday, January 25, 2015

Teardown highlights from iFixit 2015

Part of the homework this weekend is to read some teardowns at iFixit and send me an email with a link to your favorite one, with a short explanation of why it's your favorite. Here are the replies that I've received so far:
  • Pebble Smartwatch
  • I liked the teardown of the Pebble smartwatch. It was cool to see how much they packed into such a small space, especially with a large portion of it being the battery (which was only 130 mAh, but supposedly able to last a whole week). The craziest thing was that the screen had to be pried off and ended up being destroyed in the process. This was because in this version of the watch (the Kickstarter version), everything was held tightly together with adhesives. Newer versions utilize screws and are supposed to be more easily serviceable.
  • iPhone 1 and iPhone 6
  • Comparing and contrasting the original iPhone with the latest version was actually pretty interesting. It was crazy to see how much some of the components stayed the same and how much others had changed. Although the iPhone 6 is jam packed with more features and components to go with these features, it was quite a bit more organized, as all the components were smaller. I think the main reason that this was possible was because the antenna and logic board had shrunk considerably. I wonder if that’s due to new technology or better sourcing of components?
  • Tracking Device
  • I thought the tracking device looked like something that could be interesting to take apart. I mean, that’s what you do when you find FBI super-secret spy gadgets on your car. The tracker looked a lot bigger than I was expecting, and I was hoping for some military-grade stuff (…there is some mil spec velcro-ing going on though). Some cool parts of the teardown are the huge magnets, and the battery that’s supposed to last 10-20 years. I like that the screws were coated in thread lock to keep people from doing teardowns, and that the FBI was hand-soldering the board components. I also appreciated step 10 about the FBI finding you if you find their tracking device.
  • Amazon Echo
  • Echo is all about audio (both input and output), and the components inside reflect that. Amazon advertises the omnidirectional microphone on Echo strongly, and those are found at the top of the device. 6 microphones ring the perimeter of Echo, and one sits in the center. This purportedly allows Alexa to hear you no matter where you are in a room. These microphones may be Amazon-custom, as the part number doesn't appear anywhere else on the internet except in reference to the Echo. Many of the other components are specialized towards audio as well, including an audio codec, an amplifier, a digital media processor and a regulator. (Interestingly, all of the above were TI components.) The remaining components include a wifi/BT chip, flash memory, RAM, and a general processor.
  • FitBit Flex
  • I really enjoyed this teardown because I personally own this device and have thought many times about how to actually open and get into the device. Seeing that the way that iFixit approached this issue was using a saw was quite amusing. I was surprised by seeing that only half of the small device was taken up by a battery while with personal experience, the battery lasts about a week. It is crazy to see that the device was able to pack so much stuff into such little space.
  • Dell Latitude D620
  • I thought it would be cool to see a teardown of a Dell Latitude, because that is the type of laptop we are given as Olin students. Right off the bat, I was kind of surprised by how the author approached the problem. Instead of attacking the screws in the back of the laptop, he pried the nameplate off from the keyboard, and then lifted the keyboard. I also didn't fully understand everything about how the insides of a computer work, so it was cool to learn about how the CMOS battery keeps time even when power isn't supplied. I was also surprised to see how messy some of the thermal paste heat sinking was, because everything else fit together very elegantly. The teardown process was very delicate, to the point that loosening a screw too much can damage the logic board of the computer. For a lot of the teardowns I read, the process has to go perfectly for there to be any chance of reassembling the device again.
  • Occulus Rift VF Development Kit
  • Earlier this semester I was asked questions about the workings of this headset. Seeing the teardown, I was able to actually visualize the connections between the screen, speakers, camera modules, and housings in a way I couldn’t the day of those questions. If I could go back and do it again, I would have looked for something like this as preparation, but as they say, hindsight is 20/20. Another aspect I really appreciated was seeing the ease with which boards could be removed and parts could be identified. It seems to me like this represents a pretty decent way of doing a visual/digital project where you’re more likely to suffer with ribbon cables and wiley wires.
  • Blendtec Total Blender
  • My favorite teardown was the Blendtec Total Blender. Partly due to their hilarious videos but also because it wasn’t another microprocessor wrapper. Most of the tear downs of modern electronics are basically computers (which I have some experience assembling and disassembling) with a few extra components. The most impressive portion of the blender was of course the giant motor, but also the sensors that are required to maintain the motor and keep users safe. I hope by the end of the semester I can comment more on the electronic design.
  • FitBit Flex
  • I chose the Fitbit Flex because I have been interested in wearable devices for a while, and I thought it was quite interesting to see what was going on inside of one. I was surprised by how much of the interior was taken up by the vibrator, considering I had originally assumed that there would be more space required for the various components that take measurements from our body. It was also unfortunate that it was so destroyed in the process.
  • Nintendo Wii U
  • The Wii U is interesting because it has both a main station and a complex controller that have to communicate with one another with minimal lag time. The main console is impressively small and has interesting ways to fit the heat sink in the small space. The controller is even more interesting since the circuit board has to take in several inputs (including analog sticks, buttons, and even a large touch screen) which are ergonomically organized.
  • Steam Machine
  • Most of the components are off-the-shelf making them easy to upgrade. The controller has a microcontroller that can handle the user’s configured functions of the several buttons. Not only does the box contain the standard video card, hard drive, CPU cooler and power supply, but it also is prepped for another hard drive to store games on. It already contains an impressive 1 TB platter drive common in laptops, in addition to an 8 GB SSD. Unsurprisingly, the heatsink fan is huge, 80 mm, but surprisingly quiet. The on button on the console is quite large. It was surprising how much space was taken up by LED’s just to illuminate the circumference of the button but I guess this device is not built to be very compact. This device is built to be highly modular, high speed processing and have a lot of memory.
  • Nexus 7
  • My favorite teardown was of the Nexus 7. I've had to remove the back cover of my Nexus 7 several times to repair the speakers and headphone jack, but left the other components largely untouched. It was interesting to see more of what was under the battery. I found the L shape of the motherboard particularly interesting because I had always assumed that it was rectangular. It's also amazing to me how densely packed some portions of the motherboard appear to be.
  • Chromecast
  • I elected to review the Chromecast because my hall elected to buy one last semester for our communal television. Compared to a lot of teardowns that I read, this one had the most fun banter: the writers commented on how the model number, H2G2 - 42, is a reference to Hitchhiker's Guide to the Galaxy. I also thought it was interesting how they did not provide solutions for fixing the Chromecast (presumably because it is effectively impossible to repair). The teardown revealed a relatively large heat sink, but didn't explain which components would get hot. I hope by the end of EE Proto I can come back and figure it out myself.
  • Nintendo 3DS
  • What I found most surprising is how easy it is to take apart (relatively speaking) Usually Nintendo products, or game consoles in particular, are items that you'd figure are not meant to be easily repaired. But, the 3DS seems to have a ton of just simple screws, and only requires a bit of heat. Compare to some of the other consoles, and you'd be in for something much more involved. I also enjoy seeing how many cameras are employed to take the 3D pictures. As a proud owner of a few 3DS's myself, I get such a simple joy out of taking 3D pictures, and being able to tuck 4 cameras in is pretty great. Plus, it takes some pretty cool pictures.
  • Kindle Voyage
  • I had never before thought about what went into the making of an E-reader since its display is so reminiscent of newspaper ink. Aside from the humor and gadgets (a plastic card) used in this teardown, which I found delightful, I really loved learning about the multitude of sensors and ICs in this package. The PagePress force sensor reacts to an increase in pressure to trigger a page turn which is activated in tandem with a piezo haptic vibrator. IC packages streamline memory, power management, and wireless connection among additional functions. Best of all, e-paper still maintains its display even after batteries are removed!
  • PlayStation 3 Slim
  • Nest Thermostat
  • Canon PowerShot S500
  • Google Glass
  • I selected Google Glass because my friends bought one last month and I'm amazed by its powerful features. Users can take pictures, surf Internet and send message by just blinking their eyes a couple of times. I’m curious about how engineers manage to consolidate camera, smartphone, signal processing techniques and wireless transmissions into such a small volume. I thought it would be cool to see a teardown of the Google Glass and I’m eager to know the latest technologies that being used in this amazing gadget.

Thursday, January 22, 2015

Gear Teardowns

Assignment for Monday, January 26:
  1. Get a toolkit (if you don't already have one).
  2. Read Chapters 1 and 2 in "Troubleshooting Analog Circuits" by Bob Pease.
  3. Discuss the autopsy/teardown candidates with your lab partner (see exhibits A through Z in the administrative handout).
  4. Review the some teardowns at iFixit and send me an email with a link to your favorite one, with a short explanation of why it's your favorite. Be sure to venture beyond the lists of "Recent" and "Popular". For some examples, see
  5. Watch the following video (a teardown of an Anritsu spectrum analyzer from Mike's Electric Stuff; see his YouTube channel for more videos).


Good stuff.

New Term 2015

Today is the first day of EE Proto 3.0. We even have a permanent catalog number (no longer a "special topics" number). Stay tuned for new activities.