Geographical location

People are occasionally confused by the fact that I use this system in the mountains of Colorado. In fact I reside in Arlington, Massachusetts but I use this system because it's free (donations are welcome however!) and because it has the services I want.



I'm a member of the Appalachian Mountain Club, Boston Chapter. I enjoy hiking and canoeing, and I'm a regular caretaker at the cabin at Upper Goose Pond on the Appalachian Trail in the Berkshires. Volunteer caretakers are needed most years: the cabin is open from Memorial Day to mid September. Email me for details.

This is me in Bear Trap Canyon in Zion National Park a few years ago. Yes, I'm in there somewhere. Click on the pic for a better look. We got a backcountry camping permit and asked for the "Most remote site you have". They gave us La Verkin Creek Number 6, and it was certainly remote. But Site 5 is a nicer spot.
Here I am on a visit to Vinalhaven Island, Maine. Tom O'Neill took the picture.

I welcome opportunities for interesting trips and obscure, little-known destinations. I'm particularly fond of attractive ponds and streams; if you tell me about a swimmin' hole you can be sure I will show up there eventually!

Model railroads

I'm in the Tech Model Railroad Club at the Massachusetts Institute of Technology. My specialties are electronics and tracklaying. Our club uses 100% handlaid track and has a unique control system based on telephone circuits (designed before my time).

I've built control systems for 2 turntables and a radio-linked throttle using an inexpensive cordless phone. The output from the phone is sent to a microprocessor and this operates a throttle, also my own design. The pushbuttons on the phone can be used to throw switches via a serial link to the layout interface processor.

Here's a link to a paper I wrote for a magazine (it never got published) about the control system for the turntable. Now with a circuit diagram in GIF form instead of hideous ASCII!

Click here for a Microsoft Excel spreadsheet (ZIPped) which calculates spiral easements for railroad curves. You enter the radius of the curve, the length of the spiral, and the interval between calculated points along the spiral. It does the rest.

This is a picture showing our experienced software tester at work with an early version of the new control system we're working on at the Model Railroad Club. Is the interface user friendly? Why, it's so simple that even a child can do it! Or maybe it's so simple that ONLY a child can do it? That's my nephew Ben at the throttle.

Note that the diagram shows our old (pre-1997) layout.

Grey Walter's Tortoises

W. Grey Walter was a British scientist who built several mobile robots which he called "tortoises", starting as far back as 1948. He attempted to make their logical elements--a total of 2 vacuum tubes per machine--function in the manner of neurons, with the aim of making the devices exhibit lifelike (or "life"-like) behavior. At some point, I suppose around 1960, the Purbrick family saw a TV demonstration--which proved to be highly memorable--of the tortoises in action. A couple of years ago my father picked up a copy of Grey Walter's book, "The Living Brain" at a library book sale, and sent it to me as a birthday present. It included the circuit diagram and full descriptions of the tortoises, and the book inspired me to attempt to write a program which would simulate the action of "Grey Walter's Tortoise". I have to admit that I embellished the tortoise's operation and made it smoother and less erratic, but maybe also less fun. Click here for a copy of the executable program.. The source code is available if you feel the project deserves further work. Note: The program requires a display with at least 1024x768 pixels.

For those wishing further information on W. Grey Walter's work, here is a link to the Grey Walter Online Archive at the University of Western England in Bristol, which is where the picture came from.

Here is a link to some work I've done with Microchip PIC processors.


Until July '98, I was on the staff at Product Genesis Inc, in Cambridge MA, where I had the title of Senior Engineer. My degree is in mechanical engineering but I mostly do electrical design nowadays. I write software too, usually as an adjunct to hardware design. Sometimes it makes sense to have the hardware engineer get it working the first time! I enjoy an excuse to be a jack of all trades. Also, I have something of a specialty in debugging and diagnostics. This often involves some "human engineering" too.

Now I'm working on a contract basis, doing electronic and electro-mechanical design. Prospective clients are encouraged to respond.

Here's another picture, taken at my office with the Polaroid PDC-2000 camera. I did some of the design work on the shutter and lens system in this product, but alas, in spite of this it didn't stay in production long. As before, click for a bigger pic.
Somebody saw this web page and said I "must have a beautiful mother". Yes indeed. Here she is with my brother Andy, father of Ben, making Christmas pudding (It's a British thing, you wouldn't understand.)
And here's one of Dad, also with Christmas pudding.
Well, time does march on. The hopeful young lad of the earlier picture is about to graduate from high school, and here's a picture of Ben, Andy and myself while they were in the process of visiting colleges. It looks like Rutgers will have the privilege of educating him. And yes, that's Maxwell's Equations on his teeshirt.

And that's all there is.