Sunday, November 28, 2010


I did a killer ride today. Basically the Orchards plus some climbing around Harriman (Willow Grove to Gate Hill) and back-to-front over Little Tor. And then, of course, Rockland hill and the hills back from Piermont. All told, 7000 ft of climbing over 90 miles. (map) (cue sheet) Note that the cue sheet starts at the NJ side of the GWB. I forgot the cue sheet was written that way, and thus was surprised when a 75mi ride turned into a 90mi ride. But anyway.

Brad has been telling me that I go too quickly up hills, and it's somewhat sunk in. The problem has been that I didn't really internalize just how slow I could go. Today, after blowing up on Willow Grove, and almost killing myself getting to The Orchards, I slowed it down a bunch.

Here's The Orchards approach. The thick yellow line is 250 watts. I was dying by the time I reached the top of that climb.

To demonstrate that I didn't learn my lesson, here's Willow Grove to Gate Hill. Again, the thick yellow line is 250 watts. The red arrow points to the place where I had to stop to catch my breath. The eagle-eyed will note that this comes after about 0.6mi at about 300 watts. I rounded a bend which I thought marked the end of the climb, only to see (wait for it) much more climb ahead. I knew I couldn't pull that off at my current pace, and had to stop.

Why have I highlighted 250 watts? At some point after those two hills, I began to realize that I can climb significantly longer in the range 200-250 watts (preferably around 225) than if I go above 250 watts. Those who are rolling their eyes at the obviousness of all of this are requested to pretend that I'm new to all of this.

Here's Little Tor, where I began to put that knowledge into practice. Happily, the route called for a back-to-front traversal, which means a 225' climb rather than a 450' climb. I swear I did a better job at staying below 250 than this graph shows, but c'est la vie. The blips above 250 aren't due to inattention -- I was watching the power meter like a hawk the whole way up. Instead, they're where I didn't think I could stay upright at the speed required to stay in the magic range on that grade. Later on, I discovered that I could go even slower.

Now we come to some familiar hills, where I really put it into practice. By this point, I had well over a mile of climbing on my legs, as well as over 60 miles of hard riding. Had I not had this epiphany regarding the power range, I think I would've had an extremely difficult time getting over these hills. Instead, over Rockland, I was breathing hard at the top, but not panting. My breathing was back to normal quite quickly. It got progressively harder for the subsequent hills, but again no panting, and no burning -- just tiredness in my leg muscles. This is significantly different than what I normally encounter going up these hills, to say nothing of when I go up them after a crazy ride.

In the above pictures, I marked both ends of the 200-250 range. There just wasn't any point to marking the bottom end of the range in the earlier pictures.

As for nutrition, I did all of this with minimal nutrition. Water in the bottles, save for one Gatorade I picked up at Bunbury (with the worlds best muffin). While riding, I alternated between a GU and half of a Clif Bar every 30 minutes, for an intake of 200cal/hr. The riding nutrition came out to about 840 calories, to which we must add the muffin (say, 450 calories) and the Gatorade (100 calories?). That's 1390 calories taken in versus 3990 burned according to the power meter. It's worth noting that I packed riding nutrition for a 75 mile ride, not realizing it would be 90 miles (and slow). I ran out of riding nutrition several miles before Rockland Hill, but didn't really pay for it until Nyack. Nyack to Piermont was ... exciting.

And finally, pain. Soreness in my right elbow, presumably due to putting too much weight on my hands on the handlebars. The core work may actually be working, as finger numbness was minimal (versus significant in prior rides). Towards the end of the ride, my knees started to get a little bit sore on/after the climbs. I'm assuming this is because the need to stay in the power range resulted in cadences which hovered around 50. My poor knees.

Bottom line: Always listen to Brad. I'd like to do this ride again with the 200-250 range for the entire thing. I suspect The Orchards would be much easier, and that I'd be able to make it up Willow Grove without stopping. I'd also like to try Little Tor the hard way (i.e. all 450' up the front rather than just 225' up the back). Last time I attempted the front side, I had to stop twice.

Sunday, November 21, 2010

Another day, more re-learning of college math

Another day, more college math to relearn. I'm working through the first paragraph of Practical Electronics for Inventors (with the absolutely necessary errata) by my side. We've done filters, which I actually understand now, and have moved on to transient circuits. Analysis of transient circuits involves differential equations, which I'm now re-learning.

An excellent resource: Paul's Online Math Notes

Friday, July 23, 2010

Central Park Raccoons

While riding in Central Park last night, I saw a mother raccoon thinking about leading her two kids across the road right around Lasker Pool. This being quite possibly the most dangerous place to cross said road, she changed her mind, and led them back into the bush. I pointed out all of this to my riding companion.

He observed that I shouldn't be sexist. That could've been a stay-at-home dad leading the kids around.

This is true.

But I like to think that dad is still laid up at home, trying to scrub the mark from my tire off his back. If he recovers, as another friend pointed out, he'll be the only raccoon scurrying around Central Park who knows his power to the watt. Assuming he's got WKO, he can also figure out his normalized power. He didn't get my cadence sensor, though, so he's on his own for that.

Wednesday, July 7, 2010

Waddington Eastern RR

The Waddington Eastern RR (not its final name). This is what happens when you don't have any joiners, track, terminal, or otherwise.

Saturday, March 27, 2010

Work-the-hills muffin ride

The plan was to do a long ride -- Poughkeepsie, or whatever. Chatting with Brad, and given that I have only two weeks before the Princeton 200k, we decided that I should do two short rides instead. By "short", I mean 50mi -- Nyack rides. In an attempt to simulate the short, steep hills from the 200k on muffin ride, the plan is as follows:
  • Ash St both ways
  • Push every hill -- a gear or two higher than I'd normally do. This excludes state line hill and the one after that. Possibly the third big hill too.
Ash was tough going out. Even tougher going back. I worked the hills pretty hard -- or so I thought, until Brad started pacing me after we got off the GWB. I rode the Manhattan hills harder than I ever had before. Especially the ones in Central Park.

The wattage numbers for this ride should be ... interesting.

Sunday, March 21, 2010

Princeton 200k Frenchtown Asbury Practice Ride

Princeton 200k Practice Ride
Trenton Frenchtown Asbury
March 20th, 2010

I'm signed up for the Princeton 200k on April 10th. This practice ride was advertised as a way to ride the middle 50mi, including the worst hill -- on Adamic Hill Road. I wanted to see if that hill was all that, so I wouldn't have to encounter it for the first time during the 200k. This turned out to be an extremely wise choice.

The initial plan was to rent a car, drive to Frenchtown, do the ride, and drive back. This would've entailed an hour and a half drive in each direction, only to do about 50 miles of riding. It barely seemed worth doing. But wait! There's a crazy way of doing the ride! Much more fun.

The 5:15am NJT train from Penn Station to Trenton would get me to Trenton around 6:45am. A 30-some-mile flat ride up the Delaware would take me to Frenchtown, and thus the ride. Do the 53mi ride, ride back to Trenton, and we get just under a 120mi ride. Whee! That's just under the distance for the 200k (124mi), so it'd give me the same distance, if not the same exertion.

First, a word about trains which leave Penn Station at 5:15 on Saturday mornings. Last call in NYC is 4am, which ensures that the 5:15am train is chock full of club kids returning home. Such an interesting crowd. They were loud when boarding, as to be expected, but everyone quieted down pretty quickly as soon as we pulled out of the station. Everyone was either passing out or staring dully out the windows, trying to will the train to their station as quickly as possible.

I stayed up too late Friday night making my own cue sheet for the ride, and ended up getting maybe five hours of sleep (more likely less). As a result, I was pretty quiet on the train too, trying to get some sleep during the ride. I wasn't able to get any sleep on the train, but I don't think it affected the ride.

Anyway, the train pulled into Trenton on schedule, and off I went on my ride. I've gotten a lot more comfortable with the route into and out of the city, so I was over the Delaware without difficulty. The Pennsylvania side of the Delaware is impossibly scenic. The route to Washington Crossing is ok (I've done it several times now, as part of NYC/Trenton and NYC/Philly rides), but it gets even better above Washington Crossing. Barely any traffic, houses that were old when my parents were young, quaint little towns...

I liked New Hope, PA -- at 8am. On the way back, at about 2:30pm, it was overrun, but in the morning the streets were clear, leaving nothing but a quaint main street. Just north of New Hope is the intersection to the left. For me, it pretty much exemplified the Pennsylvania side of the Delaware. The road comes in, hits the stop sign between the two houses, and makes a sharp turn to wind between them. I'm sure this made a great deal of sense when carriages were the order of the day. Now, it's a reminder of time gone by.

The plan was to take River Rd all the way up to the bridge to Frenchtown, but I saw signs indicating that the road was closed beyond the bridge to Stockton. The practice ride started at 9am, and I had no time to waste back-tracking, so I decided to cross to Stockton, and to complete the ride to Frenchtown on the New Jersey side. Not very much to report between Stockton and Frenchtown -- the road was pretty flat and unpopulated. Tree-lined, some surrounding hills, the river off to the left.

And then the battery in the PowerTap hub died, just a couple of miles from Frenchtown. With it went my wattage and distance. No data for the rest of the ride. I'm convinced that made the ride seem longer, since I had no idea of my progress.

Arriving in Frenchtown, everyone had gathered in the Citgo parking lot. A quick briefing, and off we went. Overall, the ride was hilly. Very hilly. I'd been expecting something equivalent to a Nyack muffin ride, but nothing like this. The return from Nyack has long gradual hills, like the one to the NJ state line. This ride was largely composed of relentless sharp relatively short hills, punctuated by some truly evil hills.

The most memorable hill was 0.8mi on Adamic Hill Road, just outside of Riegelsville, PA, but on the New Jersey side. It's like Ash St in Piermont, only longer and steeper. To make matters worse, I was doing it on a tri bike, with a 12-25 rear cassette. Thanks to this training ride, I'll be doing it during the 200k with a 12-27 rear cassette. One only hopes that that'll be enough. I've never ridden a hill like this before. It has an average grade of about 15 degrees, with maximum grade around 25-30 degrees.

I wasn't able to make it up the hill in one shot. I had to stop twice on moderately flat sections to catch my breath. I'm proud to say that I didn't have to walk -- I was either stopped, breathing, or riding. My goal with the 12-27 is to ride the whole thing, but we'll see. A lot depends on what the first 30 miles of the ride are like.

Beyond that, nothing jumps out at me about the ride. Lots of hills, lots of beautiful NJ farmland (yes, I did actually just say that). Hopefully I'll be able to pay more attention the second time around. The hills were so tough that I spent most of this ride trying to catch my breath.

The ride back was similarly uneventful, though New Hope was a pain in the neck. Temperatures were in the 70s, so everyone and their brother was out touristing. New Hope is apparently one of the places one goes when one tourists. Traffic was backed up for at least a half mile in both directions, in and out of town, which was fun to weave through. I held a pretty good pace, though. I was aiming for a minimum of 15mph, to get me back within two hours -- in time to catch the 4:30pm train. As it happened, I made the 3:59 train.

Arriving at 6:45am, getting back to the Trenton train station at 3:45pm, gave me a 9 hour ride. That's about a 13.3mph average, though that includes all stops (at least 15min each in Frenchtown, Asbury, and Frenchtown again). A 15mph average would require an hour's worth of stopping, which is possible.

I didn't take any pictures, but I came away with a souvenir of my ride: a sunburn on my arms. I was wearing gloves and a bike jersey, which left me with a burn from mid-bicep to just short of my wrists. Extremely well defined starting and stopping places for the burn. Oh, and I noticed that my lips were getting chapped as I returned to Frenchtown, so I stopped to get chapstick. This saved me from some of the unpleasant recovery needed for the NYC-Wilmington ride.

All in all, the practice ride was the 50 toughest miles I've ever done. I'm very glad I did it, as it let me know that I need a hill-climbing rear cassette. I also need to do more hill work so rides like this don't kill me in the future. I hadn't been taking the 200k very seriously, as the distance didn't/doesn't scare me. I'm taking it seriously now, as the hills are a cause for concern. I'd been thinking I'd be able to move on to the Princeton 300k without too much trouble. Now I know I need a lot more practice. I'm confident that I'll finish the 200k -- it's just going to be hard. The first hard century I've done, so that's nice.

Thursday, March 18, 2010

Wilmington Ride

March 6th, 2010

I'd ridden NYC to Philly a couple of times. The short route (107mi) through Jersey City and Newark, which sucked, and the long route (130mi) via the GWB. The short route is not fun because you end up on US-1/US-9/Lincoln Highway (not the Pulaski Skyway, which oddly also carries US-1/US-9). A more bike-unfriendly road I've never ridden.

Going via the GWB is much better. You add twenty-some miles, but the trip is much more pleasant. The highlight is a three-mile trip through Branch Brook Park in Newark. Very little car traffic, and it's a park. Also fun are River Road along the Hackensack River (light industrial, but relatively little traffic on weekends). The rest of the detour is pretty in spots. Much better than US-1/US-9. One downside is that the Bergen Turnpike bridge just west of Ridgefield is closed until April, which requires a detour over a short stretch of US-46. That's a highway, but you're only on it over a bridge, after which you can jump off into an office park.

I had prepared for a trip to Philly, which was kinda fun, but kinda ho-hum. Somewhere in the first 10-15 miles, I made up my mind to extend it -- to go to Wilmington. That had been my next distance goal, but I'd assumed that I'd want to do the Philly ride a couple more times before going to Wilmington. I guess not. :-)

Deciding to go to Wilmington made the beginning of the ride fly by. Getting through Newark is fun (no, really), but it can get to be boring on the nth time through. Anticipation of the unknown changed that, and I was past Newark before I realized it.

One "fun" part on the way to Newark. The previous day had been warm -- above freezing -- but the previous night had been below freezing, so there was some black ice on the roads. Specifically, on 8th St in Palisades Park, NJ. A big sheet of it -- maybe 12' wide. As I approached it, I slowed down, figuring that a high-speed crash would be bad, and that I could control my bike better at low speeds. I realized, as my rear wheel slid out from under me, that 8th St is on an incline. Not in the direction of travel, but side to side. So over went the bike, and I bounced on the ground.

I picked myself up and said, out loud, "well, I'm glad I learned that lesson." A few blocks later on, there's another wide patch of black ice. This time the road is flat. So, says I, I should be able to make it over this one. Just to be sure, I'll unclip so I can steady myself. No sooner does the back tire get completely on the ice than out it goes, and down I go. Apparently I didn't learn that lesson. From now on, I'll be walking over black ice. To make it even worse, I had gone the entire winter without falling on ice. As far as I know, I've never fallen once on this bike, over the course of two years. And yet here I did, twice in less than a mile. Go me.

The rest of the ride to Philly was uneventful. I had an easier time of Cherry Valley (my traditional bonking spot) than I have in the past. The thought of going all the way to Wilmington may have helped. Nutrition was pretty standard. Alternating Clif Bar and GU every 10 miles, lunch at the deli Warren, NJ (52mi), second lunch at the State Road Deli in Croydon, PA (107mi).

I followed PA State Bike Route E around Philly. I've never gone that way before -- generally I follow Aramingo to Girard to 2nd, and into the center city. Bike Route E took me around downtown along the water (or close to it) on Columbus Boulevard. After circling the city, it's pretty much a straight shot to Wilmington via PA-291 and US-13.

I've never gone south of Philadelphia before, so I had no idea what to expect. Now I know the business of South Philly: petroleum refining. Refinery after refinery. I thought it was pretty cool -- I'm a big fan of industrial porn. There wasn't too much traffic, so it was a relatively leisurely trip, aside from the exit from Philly proper (see Route Changes, at the bottom of the post). Three things made it less fun than it would've otherwise been.

First, I left one of my bottles at the State Road Deli, leaving me with two. I finished the second one just south of Philly, leaving me dry, and didn't get around to refilling until I was well into Delaware. Second, it was getting dark. I didn't know the precise distance (I thought it was only 150mi, when it was actually 160mi), so I spent Philly-to-Wilmington pushing the pace, trying to cover as much ground as I could before the sun set. It didn't help that one doesn't find the nicest neighborhoods in the immediate vicinity of refineries. Third, I didn't get extra food at 150mi. I may not have needed food then (my second lunch was at 110mi, so it hadn't been that long), but lack of food combined with lack of fluids wore me out pretty quickly. The last ten miles were somewhat fuzzy.

Oh, and I flatted two miles from the finish. And one of my replacement tubes had a hole. I'm so happy the second replacement tube (out of two) was fine, as I had no desire to have to start walking just two miles short of my new record.

But the new tube worked, and I made it to Wilmington. 160mi. 12 hours. 4 states. Whee!

Nutrition: 7 GUs, 6 Clif Bars, 192oz of Gatorade (1.5gal), two turkey sandwiches. If we assume 400 calories for the sandwiches, that's 7x100 + 6x220 + 192*6.5 + 2*400 = 4,068. According to the PowerTap, I burned about 5,500.

Aches and pains: I took two extra-strength Tylenol before the start, and two more in Warren (52mi). That was enough to keep the lower-back pain under control for pretty much the entire ride. Some intermittent soreness in my right knee during the last 20mi and the next day.

Recovery: I was moving pretty slowly on Sunday. Knowing that Tiffany would yell at me if I didn't, I went to the gym in the evening, and did 20 minutes on the elliptical. Those 20 minutes made a world of difference.

Route changes: PA Bike Route E has you turn right on Oregon from Columbus Blvd. You then take Oregon to Passyunk, and take Passyunk over the Schuylkill. Oregon is worse than Springfield through New Jersey. Block after block of busy busy commercial traffic. Almost three miles, to be precise. Passyunk is very busy (highway, as opposed to commercial), though most of it has a bike lane. You have to use the sidewalk on the bridge over the Schuylkill, due to traffic volume and bridge type (it's a metal grid, rather than a concrete surface). There's an alternate route which looks like it might be much better.

Rather than turning on Oregon, I'd continue on Columbus Blvd, which bends right and becomes Pattison Ave. A left turn on Penrose takes me over a different Schuylkill bridge, and rejoins with the route. Pattison is green-dotted in Google Maps, which means that it's a "recommended" route. Satellite suggests that there's a wide shoulder. Regardless, it's a much less heavily-trafficked road, and runs next to a park, rather than a busy shopping/residential district. Penrose, which becomes Industrial Highway / PA-291, looks quieter than Passyunk to the bridge, at which point I have to jump to the sidewalk, just as with Passyunk. I'm going to try it next time.

Next Time: If I go 20-25mi past Wilmington, I hit Newark, DE, and then the Maryland border. That makes five states in one day. I might (very strong emphasis on might) be able to return the same day, from Wilmington, if I start at 6am or earlier. It'd be really tight, as the last Saturday night train back to Philly from Wilmington leaves at 8:30pm. There are trains as late as 11pm from Markus Hook, PA, 10mi back towards Philadelphia from Wilmington.

Electronics books

I initially started with Electrical Engineering 101, which had been pitched to me as a useful way to get a handle on the fundamentals of electronics. I'd considered Art of Electronics, but was scared away by its density. I barely made it through a chapter or two of Electrical Engineering 101 before I put it down, never to pick it up again. I'm ok with informality, but this book went well beyond that. That's a nit, though, compared to what I found to be its biggest sin. It claimed to presume nothing, but then introduced concepts out of the blue, with no definition, assuming that you were already familiar with them. Maybe I could forgive him pulling RC circuits out of thin air, but LC circuits? Really? In the chapter between Chapter 0 "What is Electricity Really" and Chapter 2 "Basic Theory"? Chapter 2 introduces Ohm's Law, so maybe I can be forgiven for not knowing the ins and outs of inductors and capacitors just yet? So away went Electrical Engineering 101.

Based on the advice of a friend, I bit the bullet and picked up Art of Electronics. It's every bit as dense as I expected it to be. Which turns out not to be a bad thing. The pace of my progress is a little disappointing (there's a lot in Chapter 1), I'm learning quite a bit. For example, I now understand that complex numbers have a purpose in life other than to fill time in High School math classes. :-)

I also picked up the companion volume -- Student Manual for the Art of Electronics. I can't imagine trying to get through AoE without the student manual -- especially as I'm doing it, on my own, without a class or professor to guide me. Perhaps the subsequent chapters are different, but the first chapter of AoE is pretty theoretical. Here's how it works, and here's how to derive the formulae which say how it works. The Student Manual, on the other hand, concentrates on how you'd do things in real life -- the rules of thumb and other tricks to make life easier. I also really really like the labs, which give me a chance to put what I'm learning into practice. Of course, going through a section in AoE, the student manual version of the same section, and the labs for the section, doing every problem along the way, is not particularly quick. I find myself wondering to what extent students do this in college. The first few weeks of any class which uses AoE as a primary text have to be just brutal, given the sheer amount of stuff in chapter 1.

But even that wasn't entirely enough. I wanted more problems to work to ensure that I understood what I was reading. For the most part, the problems in AoE don't have solutions (some are worked in the Student Manual, but they're in the distinct minority), so it's not always easy to verify that you're solving them the right way. Furthermore, many of the problems are of the form "prove this" or "derive that" -- more theoretical than practical. Which is great for learning the theory, but less good for learning the practical. I wanted another book which I could use as a fallback. If I didn't get something from the explanation in AoE (and SMAoE), I wanted a book which explained whatever it was in a (hopefully) completely different, more nuts and bolts way.

So I purchased a third book -- Circuit Design: Know it All from Newnes Press. I'm going through the 200-page fundamentals chapter. Every other page has a worked practical example. I'm doing the examples, comparing my result to the solutions in the text. It's working out pretty well. The only problem is that the first chapter of Circuit Design is littered with errors, the vast majority of which seem to be in the examples. I don't know if the rest of the book is like this -- each chapter is by a different author (or authors) -- but chapter 1 seems to have an error every few pages. Sometimes it's something simple, like a mislabeled figure. Other times, they'll say something like "figure out the voltage across R, assuming x, y, and z, with R=90ohms", and will then work the example with R=110ohms. And so on. Happily, none of the errors have been so fundamental that I couldn't catch them and compensate for them. So in a way they're a good thing, since they're helping to ensure that I actually understand what I'm doing -- that I'm not just a monkey plugging in numbers. But still, I paid $60 for this thing. They could've at least proofread it.

Monday, March 15, 2010

Power Supply

I realized that I'd need a good power supply right around the time I bought the function generator (and realized that I didn't have the 15V wall wart to power it). My requirements were:
  • Variable output
  • Visible indication (preferably digital) of voltage and current
  • Short-circuit protection
I ended up getting the Extech 382200 30V/1A power supply. I'm very happy with it. I specifically chose it over the Extech 382202 18V/3A power supply because I figure I'm much more likely to hit 18V than I am 1A. Time will tell, though I've certainly gotten pretty close to 18V with the need to provide 15V to the Nuxie function generator. Of course, now that I have a single-output power supply, multi-output power supplies are starting to catch my attention. The saving grace is that I'm very space-constrained, and barely have enough room for the one I bought.

Why am I happy with it? It's simple, it does what it's supposed to do, the adjustments aren't too twitchy, and oh my goodness is it nice to have in-line current measurement. It beats what I was doing before, when power came from a wall wart. Then, I'd occasionally put the VOM in-line, but more frequently would just hope. It's also nice to have clean power, versus whatever my wall wart was putting out. Oh, and did I mention that it handles short circuits gracefully (or claims to)?

Function Generator

I got the JYETech / Sparkfun Oscilloscope awhile back. Soon after, I realized that I'd need a function generator as well. The oscilloscope measures waveforms, while the function generator creates them. I'd had good results with the DIY oscilloscope, so I figured that I'd be similarly happy with a DIY function generator. I picked up the Nuxie / Sparkfun function generator at the beginning of February.

The assembly instructions are better than the oscilloscope ones, by leaps and bounds. Here's a picture of the finished article:

The picture on the left shows the function generator. The picture on the left is of the function generator generating a function, connected to the oscilloscope. Square waves are generated via the TTL out connectors, while the sine and triangle are generated via the wave out connectors.

Triangles can go to 6Vpp, while sine waves only go to about 5.2Vpp before the peaks start flattening out.

I had high hopes for this function generator -- hopes which were admittedly higher than they should've been. This is, after all, a $35 function generator. Some things which really started to grate on me:
  • Frequency selection is really really really really twitchy. You use the coarse pot to get close, and then use the fine pot to get closer. Trying to get within 10Hz of 1kHz or 10kHz is annoyingly hard. You get the coarse pot within a thousand Hz or so, and then use the fine pot to zero in. Only the fine pot moves the frequency really really fast. What feel like microscoping movements are enough to send the frequency zooming off by a hundred Hz or so. I'd give my left arm for some sort of calibration (and lower-resistance pots, though I could presumably do that myself) so I could easily hit a given frequency without having to spend 5-10 minutes fighting the pots.
  • Once you finally get the desired frequency, sometimes the function generator will drift off to another one -- 100Hz or so away. Which means you get to do it again.
  • The square wave is actually just TTL out, as mentioned above. So it's 0V to +5V. That's great as long as all you need is a square wave offset by 2.5V, but it doesn't work so well if you want -2.5V to +2.5V. And there's no offset knob.
  • It wants 15V DC to work properly. It's hard to find a 15V DC wall wart -- I ended up having to get one from Mouser, and the one I got was noisy enough as to throw off the function generator.
  • Now I'm just being greedy, but there's no sweep. I missed sweep when I started working on RC filters. The chip can apparently do sweep, but the circuit doesn't implement it.
Whine whine moan moan. Ungrateful me. I did point out, though, that it's really inexpensive ($35). The cheapest well-reviewed function generator I found on Amazon is $139.

Monday, February 22, 2010


The layout has to live in a small space (ideally 12"x32"). The list of gauges which can make a 180-degree turn in 1' is really short. Z gauge can do it with Marklin 8510 (5 3/4" radius) track. I can probably get a locomotive that'll handle that turn, but ... Z gauge is really small. Really really small. Putting any electronics of my own design inside a Z gauge car is likely to be really difficult. Add to that the fact that Z gauge is really expensive. Locomotives and cars seem to be twice or more expensive than their N gauge counterparts. Finally, the Z gauge world is also small. There's Marklin, MTL (Micro Trains), and AZL (American Z Lines). Oh, and Marklin just declared bankruptcy. I had an Amiga once. I don't need another.

N gauge is bigger. Bigger minimum radii (well, except for a Japan-only manufacturer named Tomix which sells 4" curves), more manufacturers (Walthers lists 2,564 locomotives in N gauge versus 144 for Z gauge), and lower prices. It's also the second-most-popular gauge in the world, next to HO. But again, the problem is with the turning radius. The smallest radius sold is the Kato Unitrack 216mm (8 9/16"). It's unfortunate (we end up with a layout that's 18"x40"), but bearable.

I don't want to use the Kato Unitrack for the real design. First of all, it commits me to designs which can be implemented using their hardware. Second, the track has integrated ballast, which always looks weird. Assuming that Atlas Flextrack can accomodate the turn radii, it should be sufficient. Unfortunately, 8 1/2" isn't the tightest turn on the layout. The turns from the switches to the crossing are sharper. I still need to find precisely the right position (possibly the angle too) for the approaches to the crossing, but I know of at least one solution which gives greater than a 6" turning radius on all four corners.

The trick now is to find a locomotive and cars which can handle a 6" curve. An initial investigation suggested that the Kato EMD NW2 was the way to go, but then I found another page suggesting that the NW2 wasn't very good at all when it came to extreme radii. That second page said the Atlas GP-35 had no trouble with 6.4". Hopefully it'll work for me too.

The Big Project

So I've decided to teach myself enough EE to let me build circuits (and, gasp, understand what I'm building). This means working my way through The Art of Electronics. It's a really good book, but it's extremely information-dense -- especially the first chapter, Fundamentals. One nice side-effect is that I now understand how trig and complex numbers are actually used in the real world. I've seen trig before when doing 3D graphics, but I hadn't seen complex numbers since ... high school? It's all very exciting.

But what will I do with this new-found knowledge? I worked my way through Computer Organization and Design while I was at Sun, and found it fascinating. I never got very far into Computer Architecture: A Quantitative Approach, but I'd like to. Either way, I'd like to use my EE skillz to build some of the circuits described in those books. Eventually, I'd like to build a processor. Even if it doesn't have a head (though that would be nice), being able to telnet or ssh into hardware I designed would be quite cool.

That's the long-term plan. What about the short term?

I just finished reading Playing With Trains, which reawakened my love for model trains. Gigantic layouts just dripping with scenery and detail are great fun, of course, but I've neither the patience nor the artistic eye for the scenery. Instead, I like the complication of the track plan.

What if I could merge model railroading, digital electronics, and software?

I'd like to build a reasonably complicated train layout that is automatically controlled. The idea is this: Start with a figure eight superimposed on an oval. Add two trains. They'll run completely automatically, without human control. Having them run in the same direction is boring. Much more fun if the first train runs on the oval while the second one runs on the figure eight. A commodity microcontroller runs the show. Its job will be to coordinate switch positions and throttle settings to keep the trains doing their thing without colliding. The faster the trains can go, the better.

Here's a really ugly picture of the layout I'd like to build/automate:

Something about the idea of two trains whizzing around that layout without plowing into each other, speeding up and slowing down on their own, switches magically switching themselves ... so awesome.

Wednesday, January 20, 2010

DIY Oscilloscope

I built the Sparkfun / JyeTech DIY oscilloscope today. The Sparkfun version comes with the surface-mount components already installed, leaving me with only the PTH components. Which probably explains why I was able to put it together with a minimum of trouble, and why it works now. Soldering a zillion surface-mount components would've been ... exciting, and probably well beyond my soldering skills at this point. I'm assuming that Sparkfun did the surface-mounting. They did a great job, as far as I can tell.

The assembly instructions are unbelievably full of suck. The first item pretty much set the tone: "Only install parts listed in the part list attached with the kit. Ignore components that appear in schematic but not in the part list." Which is certainly an ... interesting approach. Why print two sets of documentation (and of course by "print" I mean "generate PDFs") when you can print one? Users? Hah! Maybe I was just spoiled by Lego and Heathkit directions.

On the off-chance that someone other than me reads this post in the future, some warnings:
  1. Make sure to look at the picture before installing the voltage regulator. Note that there's a heatsink under said regulator. I did not. I installed the regulator, clipped the leads, and only then realized that I should've put the heatsink under it first. I'd also never used desoldering braid before (and didn't have any), so removing the regulator was all sorts of fun. Lucky for me, a) regulators are pretty tough, and don't seem to mind a little heat, b) swearing, pulling, and heating are sufficient to remove a 3-pin device without using braid, and c) I didn't have real wire-cutters, which meant that I hadn't cut the pins terribly short, which in turn meant that I still had enough length to reach the holes when I put the heatsink in.
  2. Point 5 in the notes mentions shorting JP1. Ok, do that. Don't unshort it -- you need a shorted JP1 to have a working oscilloscope. This becomes clearer once you look at the schematic. If you don't leave JP1 shorted, the LCD backlight won't turn on, and you'll measure unexpectedly-low voltages going into it.
  3. Remember to attach the 3-position switches facing the right direction. *cough*
With that all done, I now have my own working (and very inexpensive) oscilloscope. Yay me. Now I need to get a little further on in AoE so I can really use it.