Contents

The Plan

We all have working (hopefully) hardware now.  We need to get out in the halls and characterize things and then nail down our initial networking needs.  We will add in some more capacity as well by soldering in some more bits.  Here is the flow:

• Discuss our network needs
• Demonstrate the Garcia robot
• Establish our Network requirements and Specification
• Use Team Pairs to Begin Characterizing IR
• Round-Robin Soldering Session to Add Bits

Discussion

We should now have a pretty solid grasp of our networking structure and we can now establish what the primitive needs will be.  Likely candidates will be the passing of a message from one address to another, broadcasts, and possibly ping and trace capability. 

This week we also briefly mess with a SensorStick outfitted with a laser as a demonstration of how a sensor "sees" the world.  In this case, the laser is moved using another BrainStem module named the Moto which manages the precise positioning of the laser scanner to develop a 3-D point cloud of geometry surrounding the SensorStick.  This view of the room is similar to the IR communication we will be using in our project. 

We also now have 2 candidate projects that all share common network needs.  We can now specify exactly what we expect to get from our network in terms of functionality.  We can't guarantee that we will get this to work for all candidates, but we can establish what each needs and get a working definition of what we must have in our network. 

Our two proposed projects that use our IR network are the Flowerpot and Balloons.  Both use a self-forming IR communication network to give an interactive view of the communication.  The flower pot idea can use some of the network information to direct a series of flowers in pots towards people as they move throughout the network.  The balloons can be "winched" up or down on cords to a similar effect. 

Note that you will need to figure out which resistors are which in your kits.  These are coded with colored bands on the resistors.  A quick Google search should get you the coding information.  There is a .pdf file on the product page for the GP 2.0 that you can sketch your plan for adding these parts before you start soldering. 

Lab

We will now pair up teams and go out and characterize the IR capacities.  This can be organized so that one group characterizes a sunlit room, one a long hall, one a large room, and another perhaps outdoors.  We have the capacity for 4 team pairs so we can then assemble these results into a single list of rough expectations for the IR and include it in the resource information. 

While characterizing, we can rotate people out one-at-a-time to get the soldering of the additional components finished.  We will prioritize this for those people with another class right after that we can get everybody soldered up in this session...  even if it runs a bit late.  This depends on how quickly the soldering goes which is somewhat unpredictable. 

We need to solder in some new things into our boards:

• Red LED
• Green LED
• Battery Monitor

These items are simple circuits that will prove useful in the future.  Since we will be sharing code, we need to all map the same I/O ports to these new features for compatibility. 

Originally, we had planned to add the photo resistor in this step but that may not be a good idea...  depending on our destination project.  The LEDs and battery monitor are essential tools for any project so we will be adding them here. 

The LED's are outputs best suited to digital I/O pins.  Many pins have redundant holes in the prototyping area so we will use digital pins 1 and 2 for Red and Green respectively.  The battery monitor will be most effective with A/D conversion since the output is a variable voltage.  For this we will use A/D channel 0 on the prototyping area. 

Things will be a bit crowded on the proto area but we should have good results.  Each of these circuits is covered in a "howto" document on this website.  Just type "howto" into the find box to get a list for more details.  In this case that is the howto for LED to logic interface and the one for battery monitoring. 

The product page for the GP 2.0 has a PDF planning sheet you can download to sketch the additions you will be making before you begin soldering. 

The batteries were initially soldered with some stand off spacing so we can work on the prototype area.

Two 5K Ohm resistors added to act as a voltage divider for monitoring battery voltage.

Connections can be made across the backside to the I/O pins. Be sure to plan out your layout.

Assignment

We have two tasks to move forward and we will now start to diverge with our teams.  One team will go ahead and write a small system library that we will all then share subsequently.  This library will grow to offer our network API as well as the access routines for our additional LED and other monitoring hardware. 

The library will be a bit of a hot-potato shared amongst the group with teams taking turns coding, fixing, and extending the library. 

The teams not coding the library will each write (as a forum post or posts) a proposed bit-for-bit scheme for accomplishing our network specified in the discussion.  Since we have one specification and multiple teams, we will get different approaches and hopefully some of the variations can be melded into the library as our networking layer. 

Each team then has an absolute deliverable for week 4.  One team will product the initial library, the others will individually architect a networking plan and fully document it. 

Materials

We are soldering and using stems this week so we will need all the hardware and laptops (at least one per team) loaded with software and ready to go.  Also, we need to bring all batteries charged. 

The first team that brings dead batteries to the seminar gets to buy the refreshments for the final day. 

Revision History:

• 2009-01-20: Added some more notes and images, pushed off the photo resistor addition contingent on our final project plan.
• 2009-01-13: Switched the Week 2 and Week 3 demonstrations
• 2009-01-07: Initial Post

Related Links:

Main page for the University of Oregon Winter 2009 407/507 course

How To: Monitor Battery Voltage using and Analog Port

How To: Connecting an LED to logic power