Xbee Communication Part 1: Getting Started

I have spent my free time in the past few days playing with Xbee wireless modules. I move at a snail's pace because I'm terrible at managing my time effectively. I did manage to get the two modules to communicate. Not bad for like three intermittent hours of work. I spent a few celebratory minutes typing messages between the two before I decided to start making dinner.

The first step to working with the Xbees, aside from ordering the parts from Sparkfun.com, was to solder the breakout boards and wire the circuits up on breadboards. I managed to miss the recommendation that you purchase the 2mm sockets with the breakout board so that you can change the Xbee modules at a later date so I ended up soldering them directly to the breakout boards.

I also purchase a logic level converter from Sparkfun in order to step down the voltage of the serial data lines from the arduino to the Xbee from 5V to 3.3V. I had to solder header pins on this as well, but the SMD chips were already on the PCB so I didn't have to do the painstaking work of soldering those tiny things on myself.

I ran into a few problems getting the Xbees to respond to my serial commands. The first problem was that I seemed to have the TX and RX lines reversed. I could have sworn that they we wired as the diagram in Making Things Talk showed, but my mind often wanders from the page to the breadboard, so I could have been wrong. The second problem was just the fact that I had multiple serial terminals open at the same time. This resulted in some error messages or the terminals simply not responding at all. Personally, I prefer the error message, even if I didn't bother reading it.

I chatted with Lee about the problem at work and he told me about the conflict with multiple serial terminals and I was able to fix the problem as soon as I knew to only do one at a time. Now that I have the two talking I need to figure out a project where they might be useful. I'm sure that I'll think of something eventually. At least I've taken the first baby steps though.

Driving a unipolar stepper with the Arduino

I decided to get around to playing with the Arduino again. I had a few unipolar stepper motors laying around so I decided that it was about time that I figured out how to interface them with the Arduino. The first hurdle was figuring out how to wire the motors. All three of the steppers are five wire unipolar, but none of them have wires. They all have PCB's with connectors on them. I had a connector or two that I took out of an HP printer so I just had to figure out which wire did what.

Finding the center tap on the motors was easy enough as you do so by using an ohmmeter to check the resistances between pairs of wires. The common power wire will be the one with only half as much resistance between it and all the others. Finding the order of the remaining four wires in the end required good old fashioned trail and error.

When I finally figured it out I made sure to label the wires. The wiring order worked on all three steppers, two of which are Mitsumi's and the third is a Minebea.

It was easy enough to get the stepper to turn once the wiring order was determined. The Arduino stepper library provides a pretty simple method of doing so. The Arduino website gives adequate instruction on figuring out how to use it so I won't bother documenting it again. I just figured that it might be helpful to post a picture of the wiring order that I found to be shared among the steppers that I have so that I may spare someone else the effort of figuring it out in the future.

Toolbox organization

I purchased a new Craftsmen tool chest to hold my ever expanding tool collection, as well as to free my old toolbox to use for bike specific tools. I was unhappy with the lack of organization on my old toolbox. Whenever I opened a drawer tool would roll around and get all mixed up, especially my sockets as they are round and roll quite efficiently.
The first step that I took in preventing tools from rolling and sliding was to line the drawers with something that had a non-slip surface. My toolbox had foam drawer liners but they didn't really have the grip necessary to do anything more than simply protect the paint of the toolbox. I found some Con-tact brand shelf liner at Home depot that claimed to be quite grippy and when I touched it I felt that it seemed much more promising than the liners offered by Sears.
I cut the liner using a utility knife and some flooring that was leftover from my basement remodel as a cutting guide. The flooring had a cork backing that made a nice cutting surface that didn't dull the tip of my knife, and it had a nice straight edge to guide the knife with.
After the drawers were lined(Except for one as I did my math wrong and didn't get enough liner. Doh!) I wanted to make sure that I had somethign to really prevent the sockets from rolling around. I remembered that I had some Komplement drawer divider in the garage that we had forgotten to return with the Hopen wardrobe that we assembled, only to find that our ceilings were are too short to fit it. I had to modify the drawer dividers to fit and to separate the multitude of different types of sockets that I have. I used a utility knife to do this. I feel as though a small hand saw would be much better for this, but I lack such a saw, so the utility knife was what I used. The most difficult part was cutting the notches that interlock the dividers in place. The dividers are thin plywood with three plys and the middle ply was difficult to get though with the knife, but I managed. All things considered, it came out pretty well. I do want to cut the height of the dividers that run horizontally in the shelf, in order to make it easier to get to the tools in the back of the drawer and to add some labels to let me quickly see what the sockets are in each compartment. Aside from that I'm pretty happy with the outcome.

Xmas present for my sister

My sister has said for years that she would ride a bike if I found her one with a banana seat. This year for Christmas I did just that. I happened to mention to my friend Lee that I was hoping to find such a bike to give to my sister and he happened to have one in his basement. Lee has one of everything, by the way. I did some research and determined that the bike was a Ross Barracuda, made in the late sixties to early seventies.
The bike needed a bit of work, but it was in pretty good condition overall. I disassembled pretty much everything, down to the wheel hubs, and cleaned, polished or replaced anything that needed it. I decided not to go to the effort of repainting the frame as the many little rust spots gave it character, in my opinion. The only things that I ended up buying, in addition to the bike, were a bottom bracket and tires. Luckily I found a bottom bracket at Harris Cycle and tires on Amazon. Whitewalls kick ass. Below is the "after" picture. I thought it came out pretty nice and my sister seemed to agree as she jumped up and down in the driveway as I unloaded the bike from the car.

Beer Label

One of my favorite parts of the homebrewing process has always been the design of the label. I've been using the program GIMP a bit at work lately so I figured that I'd get some more practise using(at work) by designing the label for the Belgian Dubbel. As you can see from the picture I have decided to name the beer "Dubbel Track Ale". If you couldn't figure it out from the picture, double track is a term commonly used to describe a dirt road or path in which there are two distinct parallel paths; typically worn by a atv's, trucks or tractors. These are the type of trails that we rode in Colorado in September, so this is a salute to my boys, who accompanied me on the trip.

Yay! Fermentation!

Quick followup on my last post; the beer it is fermenting. I checked last night when I got home from work and there was a slow bubbling in the airlock. That's just a bit more than 24 hours later which is not bad at all. I'm really looking forward to trying this one. I think that it is going to be super tasty.

MMMmmm beeeeer...

I haven't posted anything in quite some time, but it has been even longer since I have brewed a batch of beer. With my diet and my amazing propensity for procrastination, coupled with the beer of the month club that my in-laws got me for Christmas last year, I haven't brewed in about three years or so. I decided that I wanted to make a batch for the snowshoe/skiing trip that I am going on in March and that I wanted to make a Belgian Dubble. I'm assuming that a Belgian Dubbel is similar to a German Dopplebock. I really like Dopplebocks but Northern Brewer only had Belgian ingredient kits available, so I got the Dubble. I'm not sure what I'm going to name it yet. The obvious ones are taken; e.i. Dubbel Trouble, Dubbel Barrel, etc. I may just use one of those anyway.
Having not brewed in a while I stumbled a bit, but I think that everything went pretty well overall. I do wish that I had read the instructions on the liquid yeast earlier. I’m used to the White Labs liquid yeast that comes in a test tube and you just get it up to room temperature about 3 hours before adding it to the wort(unfermented beer). The yeast that I used this time was Wyeast Labs “Smackpack” liquid yeast. In this case it was the Wyeast #1214 Belgian Ale Yeast. The “Smackpack” is an interesting thing in and of itself. Essentially, the yeast is contained in a foil-lined plastic bag, and floating in with the yeast is a small bag of yeast nutrient. As long as the yeast is refrigerated they stay dormant. When you want to use the yeast you break the inner bag by smacking the package between your hands. This pops the inner bag and releases the nutrients. You then allow the package to get up to 68-78 degrees so that the yeast wakes up, eats and multiplies. The bag is pleated on the sides to allow for expansion as the yeast multiply and give off CO₂. What I failed to read was that they recommend that you do this 3-24 hours prior to pitching the yeast, with a recommendation to stay on the longer end of the spectrum. Had I known I would have activated the yeast the night before, thus ensuring a larger amount of viable yeast.

It is very important to have yeast that is healthy and plentiful. The strain of yeast plays a large role in the flavor of the end product, and the faster the yeast starts to flourish in the wort, the less chance there is for the beer to spoil or be overtaken by wild yeasts present in the air. Wild yeasts are not necessarily a bad thing, but they make it difficult to predict the flavor of the beer. I’m kind of tempted to make a small batch of beer using a wild strain from the region. I’ve heard that yeast is commonly present on apples, hence the proliferation of hard cider in the northeast during the founding of our nation. I suppose that it wouldn’t be too difficult to make a batch of cider and take some yeast from that. It would be an neat exercise to split a batch of something like a pale ale and make half with lab yeast and half with the local yeast to compare the two. I’ll save that for another time though.

I should find out by tonight whether or not the yeast took. The airlock that prevents air from going into the fermenter, while letting CO₂ out should be bubbling by then. If not, I guess I start over. Keep your fingers crossed for me.

Ubuntu On Lappy

I downloaded the Windows Ubuntu installer, Wubi and installed Ubuntu 8.04.1. My Linksys wireless card wouldn't work but my Netgear card worked immediately. The startup is horribly slow so I want to format the harddrive and do a full install of Ubuntu on Lappy. I'm just waiting for the next realease to drop in less than two weeks. I've inserted a count-down thingy to show when it is ready.

Cyclelogue

Check out my new blog where me, Sean, J, and Tom will give the details on our mountain bike trip from Telluride to Moab at http://cycleogue.blogspot.com/.

Bike Projects

In the past few weeks I've been given two antique bicycles by friends. The first is a 1971 Schwinn Le Tour. The second is a 1983 Peugeot P6. According to the Lemonde frame size calculator, the Schwinn is pretty much the perfect size for me, being 54.5cm from the center of the bottom bracket to the top of the seat tube. The Peugeot is a bit big at 60cm. I can still mount the bike with enough clearance for the wedding tackle. Of course, the tires are completely flat so the stand-over height may be a bit big for me.

I'm thinking that the Schwinn will make a good candidate for an upgrade, while the Peugeot will make a good fixie. Aside from the fact that the frame is a bit big on the Peugeot, it also has many hard too find parts. Since the point of a fixie is to have as few parts as possible, there will be fewer parts to track down. Hopefully the bottom bracket and headset are in good shape such that I don't have to go from bike shop to bike shop looking for a stupid french replacement. The Schwinn has a non-standard fork and headset, but the headset feels pretty decent. I'll have to sit down and outline the details on the two projects. That will come at a later date. Stay tuned.