Archive for the ‘hobby’ Category

Quality hand soldering and circuit board repair: How-to manual sweats the small stuff

Sunday, October 2nd, 2011

“Quality hand soldering and circuit board repair”, by H. (Ted) Smith, is a little book with a very self-explanatory title which the average electronics hobbyist could probably get something out of reading.

The book is short, which is good because it’s really not written in a way that lends itself to enjoyable reading. In fact the author seems to be yelling at the reader for most of its 150 or so pages.

Of course the intent of the book is to be an instruction manual for manufacturing businesses and not a handbook for the average hobbyist. So a lot of the book is taken up by technical descriptions of what solder joints should look like, particularly when those might be inspected under a microscope for quality control purposes in a volume production setting.

So why should someone waste the time reading a manual that was never meant to be read by hobbyists and is a bit of a strain to read in any case?

Because there are some important things to learn from “pros” that might help an amateur save time and frustration with the craft of soldering.

For example, the soldering technique described in this book seems very different from any other appearing in any tutorial I have ever read. Mr. Smith says that the solder should be put down first, then the iron put on the solder to melt it, and then the solder moved around the joint and allowed to wet over to the iron.

Every other description of the process I have ever read says put the iron down, in contact with the pad and the component lead and then bring the solder to the joint and wait for it to become molten.

I am still not entirely sure which method is “more correct”, but it is interesting that someone who makes his living doing this stuff has such a distinctly different technique from any other source. An amateur would be foolish not to at least take into account the differences and try them out to see what works best.

The book can also give insight to the proliferation of multi-layer PCB’s, surface-mount technologies and even the causes and cures for random ESD in your workshop.

One of the most interesting parts for me––as an obsessive salvager––was the discussion of the difficulties of desoldering particularly from modern, plated PCB’s. The nature of such boards requires heating the entire board and the use of vacuum pressure to desolder any components, else the item could rebond before it can be removed (called a “sweat” joint). As a result, I am now a lot less likely to try and acquire any salvage from such boards or even to try and get hold of them to begin with. That’s a timesaver as far as I am concerned.

It’s not Shakespeare in any sense (not even Forrest Mims really), but Smith’s book is worth the short reading time even if you are not the production manager for one of Nokia’s main suppliers.

“Making Things Move”: Tinkering Manual Takes a Wrong Turn

Wednesday, September 7th, 2011

Tinkering seems a natural concomitant with the growth of the Internet: there’s a lot of information being shared out on the web and it makes a person think they can do anything . . . with tools.

As the old saying goes, “where there’s smoke, there’s a publishing opportunity” . . . or something like that.

Making Things Move,” by Dustyn Roberts (McGraw-Hill, TAB book, 2011) is a newly-published, self-styled book for tinkerers––whom the cover refers to as, “inventors, hobbyists and artists”––which aims to be the latest to take advantage of that opportunity.

The book starts by claiming that it is not about educating the reader in the sense of formal instruction; mysteriously, a lengthy introduction to the formulae, concepts, and theory of mechanical movement is presented immediately thereafter, and the discussion concludes with a homework assignment in creativity.

Sounds like formal education to me.

People don’t come to books with toy robots on the cover seeking homework assignments, particularly when those are stated as “build a Rube Goldberg device”. That’s not much to go on.

And that pretty much sums up “Making Things Move”: not much.

The text throughout is supported, seemingly on every other page, by lots of illustrations, at least half of which are hand-drawn (the inside cover lists “Sean Comeaux” as “illustrator”).

It seemed that the idea was to keep those from being “schematics” and therefore intimidating (to the “artists” maybe?), but I think that anyone picking up the book would already be beyond being intimidated by standard schematic drawings. (We might be confused by them, or misled by them, but definitely not intimidated.)

The book also refers the reader (on all of the other, unillustrated pages) to web-pages and Internet resources, (probably because there is very little useful information offered by the book itself).

There are a few tidbits in this book––the treatment of motor control is usable and a decent introduction to the problem of attaching objects like wheels and gears to bare motor shafts––but there is certainly not enough here to warrant a cover price of US$30. (The standard joke would be, “wait for the movie”, but nowadays it costs about that much to go to a movie, eh.)

Which brings me to my main negative criticism of the book: it’s all been done before. The discussion of simple machines, for example, has been done, and much more clearly so, by this Navy manual from the last century.

The bio for the author of “Making Things Move” says that she has a lot of formal training and education in engineering. That’s good because the world can always another good engineer; at the same time though, the last thing the world needs is another bad book.

After all, bad writing is what we have bloggers for, no?

How to remove Shimano BL-M200 Brake Levers

Saturday, June 18th, 2011

I was looking around the web for an explanation of how to remove the Shimano BL-M200 brake levers from the old mountain bike that I have recently (& probably “foolishly”) acquired.

I came up empty.

This is probably because these brakes are:

(1) very old (like the bike I have purchased),

(2) pretty low quality (“ditto”?),

(3) and probably should be replaced as soon as the opportunity presents itself (e.g. lottery win, surprise inheritance, found money, etc.).

Nonetheless, for posterity’s sake (and as a matter of making notes for “my-future-self”), here’s how I removed this brake lever:

(0) In these directions I refer to the black plastic part that covers the clamp as “the hood” (some drop-handle, road bike purists may take offense, but then they probably won’t be reading any blog posts about BL-M200 brake levers, eh);

(1) Loosen the cable at the brake (you don’t have to detach it completely if you’re just going to reconnect everything, just let it hang in limbo for now);

(2) Remove the tensioning screw at the lever (it’s wrapped by a spring and sticks out of the “hood”);

(3) Pull the lever, the cable should come through a bit now that it’s loosed;

(4) You should be able to see the lead weight anchor that is attached to the cable; it fits into the aluminum pull which is the part of the lever that is usually hidden by the hood when it’s all pieced together;

(5) Remove the anchor from the lever and let it hang in limbo (if you just want to remove the lever from the handlebar; if you want to replace the cable though, this is how you would pull it out of the casing);

(6) Now, pull the lever and hold it (as if applying the brake), and look into the opening where the lever meets the hood. Are you able to see the phillips head screw that tightens the clamp? If you can and are able to get your screwdriver in there, have at it;

(7) If you cannot see the clamp screw, try to remove the hood by pushing it off the clamp (away from the lever end and towards the body of the bike). Be careful, the hood is a fragile bit of plastic (and, given as old as it likely is, it has probably only gotten moreso); if it is stubborn, try prising its “wings” apart as you push it off the clamp. It will come off eventually, so don’t push it past the breaking point.

(8) Pull and hold the lever (as if applying the brake), unscrew the retaining screw a bit, and the clamp should loosen enough to slide it off the handlebar.

Now . . . how do I get it back on . . . ?

Single-speed conversions: Why?

Saturday, May 28th, 2011

I recently purchased a used (“ancient”) GT talera mountain bike from a thrift-shop for just a few dollars.

I am no expert, but it appears to be in reasonably good condition; in any event, I’m not planning any hardcore trail-riding with it.

As I was searching for info about this bicycle-from-the-last-century, I found several instances in online forums where folks much more knowledgeable than I detailed their use of GT taleras as the base frame for what’s called a “single-speed” conversion. That is, taking a multi-speed bike and turning it into a single-, or fixed-speed one (yes, I know those two things are not exactly the same as one another).

Old mountain bike frames are often the target of these rebuilds because (I’m guessing here) they were built to be pretty rugged, meaning rigid and “hard-tailed”–in the days before much suspension became common on MTB’s–so they could hold together over a lot of rough terrain (especially downhill).

All of which seems to mean that, despite the passage of time, they’re still in good enough shape to take to the streets.

I certainly understand the desire to build something from the ground up–it’s the tinkerer in all of us–but what I don’t understand is why one gear is preferable to 10, 12 or 21?

I understand that there is some advantage in terms of weight (less gears==less sprockets/chainrings==less weight), but what I don’t understand is why that’s better for street-riding?

I guess, at the very least, I should be glad that the trend seems to be giving new life to old frames, eh.

Mousey the junkbot: 5th time lucky?

Thursday, April 21st, 2011

I am not an engineer or even a good hobbyist, but I have to admit that I am quite ashamed of my inability to make any kind of simple photovore (e.g. Mousey the Junkbot) which will run properly for more than 15 seconds. (Let me add, self-defensively, that everything works like clockwork when the components are on the breadboard.)

Currently, after a long hiatus from tinkering––it’s been at least a year––I am taking a parts inventory and trying to clean up my workshop with the intent of having another go.

This will be at least try #5.

I hope this one works.

Classic MTB’s Forum

Tuesday, April 19th, 2011

If you like old mountain bikes, or are old and like mountain bikes, you’ll find this forum full of interesting posts & nice photos.

Futurlec: Electronics hobby site

Sunday, March 13th, 2011

Futurlec is a pretty good electronics hobby supply, retail website.

Good prices, but for US deliveries it is very, very slow, so be forewarned.