AT&T Archives - Check it out

I found out about the AT&T Tech Channel on YouTube.  There are numerous videos relating to AT&T and some of the discoveries done at Bell Labs.  Check out this example video on Vacuum Tubes.

Have a great weekend!

Chip of the Week: MAX21000

Hello Great Lakes Friends.  I wanted to share with you more details about the MAX21000 - Maxim Integrated's three axis gyroscope.  Its key benefits are that it operates off of 1.8V, has an internal supply for improved performance in a noisy system, and has the highest accuracy across temperature and aging.  So where could you use a gyroscope?  I included a few ideas of where they are used today:

• Motion control, gaming
• Navigation applications
• OIS/EIS
• Robotics
• Health/sports  monitoring
• Remote controllers
• Toys
• Wearable Sensors

 Below is a block diagram of the device and there is an evaluation kit available:

New Touch Technology

Hello Friends of the Great Lakes.  I hope you are well and wanted to show you a great youtube video I found of Fujitsu creating a new user interface for real-world objects.  Check out the link and let me know where you think you could use something like this:

Struggling to Select the Perfect Microcontroller

EDN had a great article this week on a subject I deal with a lot: how to select a microcontroller.  One of the particular points I enjoyed reading was on engaging with your local field engineer.  I really think a person to person dialogue about the design decisions can really help in accelerating a selection.  We are here to help!

Here is the full link - link.

10 steps to selecting a microcontroller

Jacob Beningo - April 7, 2013

Selecting the right microcontroller for a product can be a daunting task. Not only are there a number of technical features to consider, there are also business case issues such as cost and lead-times that can cripple a project. At the start of a project there is a great temptation to jump in and start selecting a microcontroller before the details of the system has been hashed out. This is of course a bad idea. Before any thought is given to the microcontroller, the hardware and software engineers should work out the high levels of the system, block diagram and flowchart them and only then is there enough information to start making a rational decision on microcontroller selection. When that point is reached, there are 10 easy steps that can be followed to ensure that the right choice is made.

Step 1: Make a list of required hardware interfaces
Using the general hardware block diagram, make a list of all the external interfaces that the microcontroller will need to support. There are two general types of interfaces that need to be listed. The first are communication interfaces. These are peripherals such as USB, I2C, SPI, UART, and so on. Make a special note if the application requires USB or some form of Ethernet. These interfaces greatly affect how much program space the microcontroller will need to support. The second type of interface is digital inputs and outputs, analog to digital inputs, PWM’s, etc. These two interface types will dictate the number of pins that will be required by the microcontroller. Figure 1 shows a generic example of a block diagram with the i/o requirements listed.

Figure 1. List of Hardware Features

Step 2: Examine the software architecture
The software architecture and requirements can greatly affect the selection of a microcontroller. How heavy or how light the processing requirements will determine whether you go with an 80 MHz DSP or an 8 MHz 8051. Just like with the hardware, make notes of any requirements that will be important. For example, do any of the algorithms require floating point mathematics? Are there any high frequency control loops or sensors? Estimate how long and how often each task will need to run. Get an order of magnitude feel for how much processing power will be needed. The amount of computing power required will be one of the biggest requirements for the architecture and frequency of the microcontroller.

Step 3: Select the architecture
Using the information from steps 1 and 2 an engineer should be able to start getting an idea of the architecture that will be needed. Can the application get by with eight bit architectures? How about 16 bits? Does it require a 32 bit ARM core? Between the application and the required software algorithms these questions will start to converge on a solution. Don’t forget to keep in mind possible future requirements and feature creep. Just because you could currently get by with an 8 bit microcontroller doesn’t mean you shouldn’t consider a 16 bit microcontroller for future features or even for ease of use. Don’t forget that microcontroller selection can be an iterative process. You may select a 16-bit part in this step but then in a later step find that a 32 bit ARM part works better. This step is simply to start getting an engineer to look in the right direction.

[Click below for more steps]
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Step 4: Identify Memory Needs
Flash and RAM are two very critical components of any microcontrollers. Making sure that you don’t run out of program space or variable space is undoubtedly of highest priority. It is far easier to select a part with too much of these features than not enough. Getting to the end of a design and discovering that you need 110% or that features need to be cut just isn’t going to fly. After all, you can always start with more and then later move to a more constrained part within the same chip family. Using the software architecture and the communication peripherals included in the application, an engineer can estimate how much flash and RAM will be required for the application. Don’t forget to leave room for feature creep and the next versions! It will save many headaches in the future.

Step 5: Start searching for microcontrollers
Now that there is a better idea of what the required features of the microcontroller will be the search can begin! One place that can be a good place to start is with a microcontroller supplier such as Arrow, Avnet, Future Electronics or similar. Talk with an FAE about your application and requirements and often times they can direct you to a new part that is cutting edge and meets the requirements. Just keep in mind that they might have pressure on them at that time to push a certain family of microcontrollers!

The next best place to start is with a silicon provider that you are already familiar with. For example, if you have used Microchip parts in the past and had a good experience with them, then start at their website. Most silicon providers have a search engine that allows you to enter your peripheral sets, I/O and power requirements and it will narrow down the list of parts that match the criteria. From that list the engineer can then move forward towards selecting a microcontroller.

Step 6: Examine Costs and Power Constraints
At this point the selection process has revealed a number of potential candidates. This is a great time to examine the power requirements and cost of the part. If the device will be powered from a battery and mobile, then making sure the parts are low-power is absolutely precarious. If it doesn’t meet power requirements then keep weeding the list down until you have a select few. Don’t forget to examine the piece price of the processor either. While prices have steadily been approaching $1 in volume for many parts, if it is highly specialized or a high-end processing machine then price might be critical. Don’t forget about this key element.

[Click below for more steps]

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Step 7: Check part availability
With the list of potential parts in hand, now is a good time to start checking on how available the part is. Some of the things to keep in mind are what the lead times for the part? Are they kept in stock at multiple distributors or is there 6 – 12 week lead time? What are your requirements for availability? You don’t want to get stuck with a large order and have to wait three months to be able to fill it. Then there is a question of how new the part is and whether it will be around for the duration of your product life cycle. If your product will be around for 10 years then you need to find a part that the manufacturer guarantees will still be built in 10 years.

Step 8: Select a development kit
One of the best parts of selecting a new microcontroller is finding a development kit to play with and learn the inner working of the controller. Once an engineer has settled their heart on the part they want to use they should research what development kits are available. If a development kit isn’t available then the selected part is most likely not a good choice and they should go back a few steps and find a better part. Most development kits today cost under $100. Paying any more than that (unless it is designed to work with multiple processor modules) is just too much. Another part may be a better choice.

Step 9: Investigate compilers and tools
The selection of the development kit nearly solidifies the choice of microcontroller. The last consideration is to examine the compiler and tools that are available. Most microcontrollers have a number of choices for compilers, example code and debugging tools. It is important to make sure that all the necessary tools are available for the part. Without the right tools the development process could become tedious and expensive.

Step 10: Start Experimenting
Even with the selection a microcontroller nothing is set in stone. Usually the development kit arrives long before the first prototyped hardware. Take advantage by building up test circuits and interfacing them to the microcontroller. Choose high risk parts and get them working on the development kit. It may be that you discover the part you thought would work great has some unforeseen issue that would force a different microcontroller to be selected. In any event, early experimentation will ensure that you made the right choice and that if a change is necessary, the impact will be minimal!

Jacob Beningo is a lecturer and consultant on embedded system design. He works with companies to develop quality and robust products and overcome their embedded design challenges. Feel free to contact him at jacob@beningo.com or at his website www.beningo.com.

TI Employee BoosterPack Challenge

It looks like TI is offering a design challenge to their employees to build a great booster pack.  I can't wait to see what designs come out of this.  I started to review some of the submissions and saw my obvious favorite, a quad copter booster pack.

You might be unsure of what a booster pack is.  A booster pack is an add on board that mates to TI's microcontroller development kits.  These development kits are called launchpads and they are available for TI's 16bit MSP430, their C2000 DSP line, and their ARM Cortex M4 microcontroller line.  There are numerous booster packs available and TI has straight forward instructions on how to build your own - link.

Here is a link to the employee entries thus far - link.

I saw this article and needed to repost.  Please exercise caution if you attempt to built this.  Here is the full link to the instructions - link:

DIY Laser Cutter for PCB Stencils

Friday, 29 March, 2013 18:27 Last Updated on Friday, 29 March, 2013 23:14 Written by NJC

20 Comments

Introduction

Are you sick and tired of using a tooth pick to apply solder paste? Are you still using through hole components because you don’t want to deal with soldering surface mount devices (SMD)? If so, this post provides you with guidelines for building your very own laser cutter for cutting PCB stencils. With a total cost of approximately $200 (it can be significantly less if you already have parts laying around), this project can pay for itself very quickly. While you can get “low cost” stencils for your PCBs, they still can be quite expensive if you are only creating one or two boards.
The laser cutter can cut very accurate stencils from adhesive backed black vinyl sheets (on Amazon) for ICs with a pitch of 0.5mm (SON-10) and 0402 resistors (and possibly even smaller parts). These stencils are disposable and so cheap that you do not have to worry about using your stencils on one or two PCBs.

It gets better. You can use your RepRap as a laser cutter. All you need is a laser, a laser driver circuit board, and updated firmware (see below). While I built my laser cutter to be a laser cutter and not a 3D printer, I still used the RAMPS for the electronics even though it was built for the RepRap.
Before going onto how I built the laser cutter, I want to give you a quick overview of the design flow once everything is up and running:

• First, I create a circuit board and order it from either Seeedstudio or OSHPark. Eventually, I will be using HackEDA for my schematic designs (go check them out!).
• Next I make sure I have all the components I need.
• Once the boards arrive, I export the gerber files for the stencils from Eagle CAD using a simple CAM processor.
• I then run a custom Python script which reads a gerber file and outputs a G-code file that the RAMPS electronics can understand.
• Using pronterface (a RepRap interface software), I control the laser via G-code creating the stencil
• A few minutes later, a perfect stencil has been created!
• Using a credit card or razor blade I apply solder paste to the board.
• I then manually place the parts using tweezers (sadly I do not have a pick and place machine…. yet).
• Finally, I carefully place the populated board in my toaster oven reflow oven.
• Approximately 5 minutes later, a perfectly soldered surface mount PCB is ready to be tested!

It has literally never been easier to build a custom circuit board. One of the best parts of this project is that most of the software needed was already written. This makes it VERY easy get going once the build is complete. Never reinvent the wheel if you can help it! That being said, you can buy a cutter/plotter for $250 on Amazon and make stencils that way. I believe that I will be able to achieve significantly higher accuracy with no software magic using my custom laser cutter. This is a much “simpler” alternative that may not provide as good results for approximately the same price.