Welcome to ME102, "Mechatronics"

Lecture Notes

H-bridge lecture notes are now up.

Lab 2 Bug Report

While most groups successfully completed lab 2 without many problems, there were a couple of groups that spent more time than anticipated due to a bug with the provided sample code. The bug is simple, but it occurs multiple times.

int pwmPins[] = {11, 10, 9, 6, 5};
...Some code
for (int i = 0; i<=5; i++)

pwmPins is declared in the beginning as an array of length 5. However, it is later accessed in the for loop for indices 0 through 5. This presents a problem. Unlike Matlab, which starts counting arrays at 1, the Arduino language uses a more popular convention by starting counts at 0. So pwmPins[0] returns the 1st element in the array.

Nothing is problematic until you reach the point where i = 5. Code that then tries to access pwmPins[5] then becomes meaningless. Many of you managed to get to the checkoff without being hindered by this bug. However, a frustrated few definitely encountered this mistake.

While the fix is trivial (all you have to do is change the for loop so that it iterates from 0 to 4), the implications are not. The Arduino IDE will catch compilation errors that are generally syntactic, but run time errors such as the familiar (Index OutOf Bounds) will probably not be caught. Therefore, be careful when thinking through code for your project. Errors in logic are much harder to debug than things such as a missing semicolon.

This bug has now been fixed. Please let your GSI know if you encounter any further difficulties.

More OH's

Sarah now has office hours on Thursday from 2-330pm.

Project Proposals and OH's

On the presentations this coming week:

• Please send your project proposal in two pages of power point to your GSI
• All students names must appear on the proposal first page
• All members should come to the presentation.
• You only have three minutes to present you project.
• Not all members need to talk; only one or two people should present the work.
• We must receive the proposal by Sunday night. This is going to take the place of the written portion--you do not need to turn that in.

Additionally, Andrew now has office hours in 2168 Etcheverry on Thursdays from 330-5 and Friday from 1-3. The course info has been updated to reflect this.

Project Proposals
DUE: Sept. 21/22

Write 1-2 pages on your project (double spaced).  Include a brief
description of the problem and why it’s important to solve, and a more
detailed description of how you intend to solve it.  Your description
should explain what kind of sensors, actuators, and other major
hardware components you will need and how they will interact to form
your device.  You should specify type of hardware but do not need to
know what specific model/make you will use (e.g. if you need to know
temperature, saying you need a radiation temperature sensor is
fine—you don’t need to know you will be using the Foobar TempMaster
101 Alpha).  You should, however, make sure what you want exists and
is feasible for you to acquire and use.

Project Drawings
DUE: Oct. 5/6

Solid model your device and submit drawings of the solid model.  Use
whatever CAD software you are familiar with.  For every part, submit a
drawing detailed down to the bolt holes you will use to connect the
parts.  Show relevant dimensions.  Submit an assembly drawing that
shows the overall form of the device.  The drawings should give a
detailed picture of the inner workings of your device, and should be
sufficient as blueprints to build it.  Also submit a list of parts you
will need.  You do not need to submit drawings of common stock parts
(e.g. bolts, nuts, etc).  After submitting these drawings and
receiving feedback from the GSIs, you should begin fabrication of your
device.

Hardware Checkpoint
DUE: Nov. 2/3

All hardware for your device should be manufactured and assembled.
Custom parts should be machined and shown to work.  Sensors should be
mounted, motors should be connected to shafts, and pretty flashing
lights should be in place to flash prettily.  You should be able to
show you know how to control your actuators (e.g. what voltage to
apply to motors) and what output your sensors give you (e.g. if you
have a light sensor, hook it up to a multimeter and show its output
change with varying light levels).  It is ok if small adjustments need
to be made for fine-tuning, but no major work should still need to be
done.  You should spend the majority of your remaining time writing
and debugging the code to control your device.

Presentations/Open House
Nov. 30, Dec. 2

Show off your work!  For the presentation, show us your functional
device.  For the open house, put together a poster (or more) to
showcase your invention to the public.

Lecture notes from yesterday, as well as for next Monday are now online.

• Inputs and Outputs
• Pulse Width Modulation

All lectures will be held in 277 CORY from now on.  Lecture times and days are unchanged.

Lecture notes from yesterday are also up

• Introduction to ADC

Hi all,

The Arduino board kits are ready for pickup. Tom Clark will be distributing them in 2113 Etcheverry on Friday, Sept. 4, from 8:30-10:30am and 11am-5pm. He will be out to lunch for ~30 minutes around lunchtime. Please stop by with your group and pick up one kit for the group during this time. You'll need the kit during your next lab session, so remember to bring it with you.

Andy

Hi ME 102

So, many of you may be wondering when and where to get your Arduino Kits to complete the lab assignments. The kits are being currently assembled and tested. As soon as they are completed they will be available. Stay tuned for more details.

Thanks for your patience as the semester gets underway.

On a non-lab related note, lecture notes for today are now up:

• Microprocessors in Mechatronic Systems
• The Microprocessor
• Memory Architecture

There have a number of questions about which Arduino board should be used for ME102. Please note that lab kits will be provided. The lab kits will contain the Duemilanove as well as the sensors and actuators needed to complete the labs.

That being said, the Arduino website features many boards such as the Duemilanove, Nano, Mini, Pro, Mini Pro, Mega, and Lilypad. The standard Arduino boards is the Duemilanove and the largest difference amongst the available options is the size of the board. A comparison can be found here. To shrink the board size down from the Duemilanove, a number of convenient features such as overcurrent protection, USB connectivity, and easy-access pins are no longer there.

The ME102 labs were written with the Arduino Duemilanove that have the Atmel 328 chip in mind. This is the most recent version of the Duemilanove, and offers expanded memory in comparison to the Duemilanoves with the Atmel 168. If you wish to buy your own boards for lab, buy the boards with the Atmel 328. A fellow classmates has found an online retailer that sells them for $30 (S&H inclusive).