Brooke's World The life and ramblings of Brooke.

Task

Find the following types of components

• Digital to analog converter (DAC)  ( Cut Tape/Tube, 8-10bit, SPI,
  • Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22249A.pdf
  • Digikey: MCP4812-E/SN-ND
  • Mfr: MCP4812-E/SN
  • Price: $2.53
  • Package: 8-SOIC (0.154″, 3.90mm Width)
• Potentiometer ( digital or analog?, how many watts?, trimmer pot? tolerance?  Ohms?)
  • Datasheet: 
    
  • Digikey: 
    
  • Mfr: 
    
  • Price:
  • Package:
• MOSFET ( I don’t even have enough information to start.  There are two many even main categories of MOSFETs and I cannot figure out where to start ) ( Mosfets, FETs – single, Packaging: Cut Strip/Cut Tape/Tube, Mounting Type: Surface Mount, Package/case: TO-252 –  TO-268 the D2PAK ones, FET Type: N Channel, )
  • Datasheet:  http://www.diodes.com/_files/products_inactive_data/DMN3020LK3.pdf
    
  • Digikey:  DMN3020LK3-13DICT-ND
    
  • Mfr: DMN3020LK3-13
    
  • Price: $0.59
  • Package: TO-252-3, DPak (2 Leads + Tab), SC-63
  • Drain to Source: 30V
  • Current continuous drain:  11.3A
• Sense Resistor
  • Datasheet:  http://www.bourns.com/data/global/PDFs/crt.pdf
    
  • Digikey: CRT0805-BY-1004ELFCT-ND
    
  • Mfr: CRT0805-BY-1004ELF
    
  • Price: $0.51
  • Package: 0805 (2012 Metric)
  • accuracy: ±0.1%

Recall the following design goals:

• Swappable components with easy to solder packages.
• Low cost.
• SPI DAC part with 8- 10 bits.
• MOSFET capable of carrying half an amp in a surface mount package.
• Moderately accurate sense resistor.

Task

• Create a current source with a voltage input, using an op amp.
• Add in an optional DAC to control the current source with voltage readback

Schematic

Git Repository: https://github.com/hedrickbt/ContextualElectronics/tree/Module3Unit4/Session1/MyBenchBuddy

Task

Find the following types of components:

• Quad op amp for making a instrumentation amplifier ( <= 1na input bias I, cut tape, < 500 uv input voltage offset, +/- 12V input range )
  • Datasheet: http://www.ti.com/lit/ds/symlink/opa4170.pdf
    
  • Mfr:  OPA4170AIDR
    
  • Digikey:   296-29664-1-ND
    
  • Price: $2.58
  • Package:  14-SOIC (0.154″, 3.90mm Width)
• Temperature sensor with a simple analog output ( temperature sensor/transducer, cut tape, accuracy <= +/- 1C, sensing 10C-125C exclud. trip point ones )
  • Datasheet:  http://www.ti.com/lit/ds/symlink/lmt86.pdf 
    
  • Mfr: LMT86DCKT
    
  • Digikey:  296-35729-1-ND
    
  • Price: $0.73
  • Input V:  2.2-5V
  • Package: 6-TSSOP (5 Lead), SC-88A, SOT-353
  • Supply I: N/A
  • Accuracy: ±0.4°C
• Analog digital converter with 2+ inputs (so we don’t need an external mux) ( analog front end, cut tape + tube, 2+ channels, 16+ bit)
  • Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22286A.pdf
    
  • Mfr: MCP3911A0-E/SS
    
  • Digikey:  MCP3911A0-E/SS-ND
    
  • Price: $2.33
  • Input V: 2.7 V ~ 3.6 V analog/digital
  • Package: 20-SSOP (0.209″, 5.30mm Width)
  • Supply I:
  • Bit: 24
  • Sample Rate: 125KSPS
  • Channels: 2
  • Chris actually chose 3901 due to part availability

Recall the following design goals:

• 16+ bit input
• Low cost
• 1 degree C accurate (aim for .5 C accurate)
• Swappable components
• Easy to solder components

Task

• Create a block diagram for the thermocouple measurement circuit in Kicad.

Github:  https://github.com/hedrickbt/ContextualElectronics/tree/Module3Unit3/Session1/MyBenchBuddy

Task

1. Create a schematic with a heirarchical page for each block in the block diagram.
2. Add some hierarchical labels within one of the sheets.
3. Exit the sheet and import the heirarchical pin to the top level heirarchy symbol.

Github:  https://github.com/hedrickbt/ContextualElectronics/tree/Module2Unit9/Session1/MyBenchBuddy

Measure or look up the dimension of an Arduino Uno. Compare against other versions of Arduino.

• Measured: 2.691″ x 2.1020″
• Looked Up:  http://arduino.cc/en/Main/arduinoBoardUno  2.71″ x 2.1″ maximums
• Leonardo: Same  http://arduino.cc/en/Main/ArduinoBoardLeonardo
• Due:  4″ x 2.1″  http://arduino.cc/en/Main/ArduinoBoardDue
• Mega 2560: 4″ x 2.1″  http://arduino.cc/en/Main/ArduinoBoardMega2560

Verify the pin pitch of the stackable connectors on the edge of the Arduino.

• Measured: .103″
• Looked Up: http://arduino.cc/en/Main/arduinoBoardUno  .100″ ( aka 100 mil )

Enter the board outline of the Arduino into PCBnew for a rough 2D guideline.

• https://github.com/hedrickbt/ContextualElectronics/blob/master/Session1/Module2/Unit11/BoardEdgeLayout.png

If you want to participate alongside, do the following (before watching the execution video):

• Create a new repo in GitHub for a project:  ContextualElectronics
• Create a new project in the KiCAD launcher of your choice of name and location.: MyBenchBuddy
• Create a blank schematic file:  MyBenchBuddy.sch
• Create a blank layout file.:  MyBenchBuddy.kicad_pcb
• Push your files to the rep :  https://github.com/hedrickbt/ContextualElectronics/tree/master/Session1/MyBenchBuddy/KiCad

List your biggest failure in a project ever on the forum thread for this course unit.

• A software project that a significant amount of time was spent on.  We delivered the project and the customer didn’t feel they received what they expected.  The biggest issues weren’t technical at all.  The issues were that our communication wasn’t  as good as we thought.  This was an important lesson that I was lucky to learn early on.

In the event you’ve never had a big failure, explain why you think that is.

• I know I shouldn’t answer this one too.  I fail all of the time.   While trying to think of really big failures I struggled.  I just try to manage failure in small bites where possible.  This means that recovery from failure doesn’t have to be as big of an obstacle as it can be when we fail really big!  Unfortunately I don’t get to tell the fun and spectacular failure stories.

I am participating in an online course called Contextual Electronics – Session 1.  I will be posting my answers to quizzes and homework here.