RCA Over Cat5

November 4th, 2007 No comments

I spend a lot of time in my kitchen, cooking up some hopefully tasty creations. With our recent move, our kitchen was upgraded considerably. In the apartment, I could hear the TV and even watch it, albeit at a viewing angle approaching 180 degrees. In our new place, the TV in the living room isn’t visible from the kitchen, and I was getting lonely and bored cooking while the TV was on in the other room.

Our New KitchenOur recent subscription to Rogers’ Digital VIP pack includes a SD digital box that we weren’t going to use in the living room. So we, and by ‘we’ I mean ‘I’, decided to buy a small TV and mount it on a wall in the kitchen. The only problem is that if you look closely at this picture, there is no cable outlet in the kitchen. There is, however, a Cat5 drop here, running from the ground floor.

WiresMoving down to the ground floor, we find the utility room that houses our washer & dryer, furnace, and hot water tank. This is also the room where the cable and phone lines come in from the outside, so our cable modem and wireless router live here too. It’s a big mess right now, but clean-up is on the low-priority to-do list, and I’m not too keen on spending too much on making this room pretty, especially since we are renting.

After some research, and a failed attempt at just soldering the RCA wires to the Cat5 twisted pairs (Yes, I knew there is an impedance mismatch, I just wanted to see for myself), I went to Home Depot and they had what I was looking for:

What these do is let you use one twisted pair to send one of the three RCA signals, yellow for video, red and white for audio, over one twisted pair of Cat5 cable. There are 4 twisted pairs in one Cat5 cable, so you can use 3 for the RCA signals and have one to spare, which you can run a telephone over if you wish. They were about $5 each, and I needed 6, 3 for each end. Perfect for my situation!

The 40735-R*W units come with everything you need to get them attached to your Cat5, so other than something to strip the twisted pair wires inside the Cat5 cable, you don’t need anything special to get this working.

So in the basement, we have the cable box, RCA wires, and the QuickPort connectors:

There were 3 Cat5 wires there, going to the master bedroom, the guest bedroom, and the kitchen. To figure out which one to use, I guessed. Got it right the first time. =)

So on we move to the kitchen. It’s the same process, plug some Cat5 into the wall socket, slice off one end and put on some more of my favourite new connectors:

I picked up a 19″ LCD TV, a Sharp LC-19SB24U. It has a really thin bezel, which makes it look quite sleek in the kitchen. To mount it to the wall, I picked up a mount (00K79.21) at the Lee Valley showroom / warehouse here in Ottawa. I found out that Lee Valley has some great prices on these from my favourite home-theatre forum: Digital Home Canada.

I decided to put it on the wall where you see it so that I can put it out of the way when I don’t want the LCD close the kitchen work area. Here it is mounted to the wall:

So it all worked out pretty well. Here are some shots with the TV in the cooking position and in the safe at home position:

So at this point in time there are a couple of things left to do here, clean up the wires, and implement some sort of IR transmission system so I don’t have to walk down to the laundry room every time I want to change channels!

The last picture I have is of the wire management package that I picked up at Home Depot. I just need to pick up a white Cat5 cable to run from the wall up to the back of the TV:

So, it’s been a fun project… and now I can watch Sportscentre in the morning making breakfast and the Habs while making dinner =). If you have any comments, let me know at ken@kje.ca.

Categories: Tech

MLB Simulator

April 2nd, 2007 No comments

From a link that was in the paper mentioned in the previous post, I started to read about RIOT, the MLB simulator at Berkeley. Here is an excerpt from their page:

Calculating the clinching and elimination numbers for the RIOT baseball standings involves systematically searching for scenarios in which particular teams finish with or without gaining playoff berths. For example, we determined that San Francisco was eliminated from first place in the National League West on September 8th by proving that no feasible scenario exists in which the Giants win the division. The problem of determining whether a team can advance to playoffs given the current league standings and schedule of remaining games can be solved by a single maximum flow calculation (see Hoffman and Rivlin [1] and Schwartz [2]). By introducing additional constraints, we extend this maximum flow formulation to derive integer linear programming problems which find the minimum number of games a given team must win to clinch a playoff spot or avoid elimination from post season play. Robinson [3] takes a similar approach to finding a scenario which maximizes a given team’s lead in the final standings. Interested readers should also consult Gusfield and Martel [4], who show how to find the minimum number of games a team must win to avoid elimination from first place by solving a parametric minimum cut problem.

Very neat. Click here to download their paper.

Categories: General

NHL Simulators

April 2nd, 2007 No comments

If you google for nhl playoff simulator my NHL Eastern Conference Playoff Race Simulator comes in at #3 in the search results. While I was checking my Google ranking, I found a paper written by some professors from the University of Alberta where they used some simple Monte Carlo simulations in Excel to simulate the end of the 2004 NHL regular season, and then the playoffs. If you are of the less math-inclined persuasion, skim sections 2 and 3, but be sure to read at least section 4. Here is a reference to the paper:

Ingolfsson A. (2004), “Simulating NHL Games to Motivate Student Interest in OR/MS,” INFORMS Transactions on Education, Vol. 5, No 1, http://ite.pubs.informs.org/Vol5No1/Ingolfsson/

Categories: General

MATLAB Vectorization

March 19th, 2007 No comments

After reading up on MATLAB vectorization last week, I wrote this code to normalize each row of a N by 3 matrix. The speedup is not enourmous, but it is significant. I tried timming things this weekend on my computer at home, but MATLAB on a 1GHz G4 with 512MB of RAM is not what you would call ‘peppy’. I’ll try on a modeling workstation at the office today and see what’s what when we try a big matrix and it can stay all in memory.

function [ ] = unit_vector_rows_for( N )
%UNTITLED1 Summary of this function goes here
% Detailed explanation goes here

%make a 1×3 matrix, we will consider rows as 3-tuples
a = [1:3] ;

%repeat a so that it becomes a N by 3 matrix, so we can have a big one to
%test

a=repmat(a,N,1);

tic
for i=1:size(a,1)
a(i,:) = a(i,:) ./ norm(a(i,:)) ;
end
k=toc;
fprintf(‘For loop time is %f\n’,k);

function [ ] = unit_vector_rows_mat( N )
%UNTITLED1 Summary of this function goes here
% Detailed explanation goes here

a=[];

%make a 1×3 matrix, we will consider rows as 3-tuples
a = [1:3] ;

%repeat a so that it becomes a N by 3 matrix, so we can have a big one to
%test
a=repmat(a,N,1);
tic
a = a./repmat(sqrt(sum((a.^2)’))’,1,3);
k = toc;
fprintf(‘Vectorized time is %f\n’,k);

Categories: Tech

Laurentian Aerospace Corp.

January 30th, 2007 No comments

Check out the new Laurentian Aerospace Corp website, put together by yours truly!

Categories: General