MECH307 - Useful Project Advice

• If you haven't done so yet, carefully read:
  • Chapter 7 in the course textbook (especially the Threaded Design Examples with full hardware and software examples, with video demonstrations).
  • Labs 9-11 in the course Lab Book.
  • "Lab" 15 in the course Lab Book (contains lots of useful project-related advice).

• Anytime you want info or examples dealing with a specific topic, the project resources page is a good place to start.

• Read all of the project lessons learned from past students. And when you are researching and wanting to purchase components for your project, see: useful local and online vendors and components recommended and used by past students.

• Use devices on the Useful PIC I/O Devices page instead of trying to design and build them yourself (especially H-bridges and stepper motor controllers).

• Research and order free samples for any PICs needed via these links:
  • Microchip page for selecting appropriate PIC16F8x series 8-bit microcontrollers
    • Important columns to consider:
      • I/O pins.
      • package: PDIP (plastic dual in-line package), not SOIC (small outline surface-mount IC)!!!
    • Make sure the selected model is supported by the Lab software before ordering. Make sure it is listed in the software, and make sure a test program compiles before placing an order.
    • Use the PIC16F88 where possible:
      • most familiar from Lab work.
      • can use multiple PICs in design if necessary (and to subdivide tasks and I/O demands).
    • If you plan to use a PIC other than the PIC16F88:
      • see the data sheet (e.g., see the PIC16F88 data sheet) for:
        • pinout diagram and the special features summary (and print and insert this in your design notebook).
        • "Oscillator Configurations" for "OSCCON" settings.
        • "I/O Ports" for pin functions (e.g., open-drain or not, Schmitt Trigger, weak pull-ups, analog/digital, etc.) and important "Special Function Registers" (e.g., ANSEL, with details later in data sheet in "Analog-To-Digital Converter (A/D) Module").
  • Microchip page for ordering free samples

• Be sure to look at the "Electrical Characteristics" section of the data sheet of the PIC (or other microcontroller) you are using to be aware of current limitations for each pin, each port, and the entire chip. If the currents are not sufficient for the external components you are using, you will need to use transistors, relays, and/or buffers to boost output currents.

• PIC programming advice and help:
  • Always start with the PIC16F88 code template on the Lab Book resources page and the Blink program (from Lab 9).
  • Divide and conquer (implement and test only one thing at a time).
  • When debugging (finding errors), remove (or comment out) all nonessential and non-related code to help you narrow down where the error might be occurring (and add Lcdout commands throughout to help track and diagnose the problem).
  • Implement an LCD early in your design (even if it isn't required in the final solution) so you can display messages and values while developing and debugging.
  • When having trouble, carefully read the command descriptions in the PicBasic Pro manual (printed copies available in the Lab) and study the examples in the textbook and in the PIC section on the project resources page.
  • Be very careful with Configuration Settings every time you compile a program onto a PIC (e.g., if the Code Protect bit is ON, you will never be able to program that PIC ever again. Also, if the I/O pin functions are not set correctly, the I/O won't work properly). See the PIC16F88 code template and the PIC programming procedure for information on how to automate this.
  • If you want to study and learn from various examples of PicBasic Pro code, many are provided under "PIC - programming examples" on the project resources page.

• Be very careful when applying power to circuits and sub systems (e.g., actuators).
  • If using a variable-voltage power supply, set the voltage before cables are attached to your circuits.
  • If using more than one power supply (or battery or AC adapter), with different voltage levels, be very careful to not switch them by mistake.
    • Applying a high voltage to a PIC or other digital IC will damage them instantaneously and permanently.
    • Consider using different connectors for the different supplies to prevent a possible mistake (which can be very costly and time-consuming to fix).
  • If using an AC cable to power components in your project, attach earth ground to your project chassis (or electrical enclosures) to prevent a shock hazard and to help provide shielding from EMI.
• Watch as many videos as possible on the YouTube Channel: Great Scott (for lots of fully-documented mechatronics projects ideas).