Feels Like the First Time

I started soldering when was about 10 years old, and I have hundreds of hours of soldering experience under my belt.  Having said that, my first foray into surface mount soldering made me feel like a novice all over again.

The Final Expansion 3 cartridge (an SD card floppy drive emulator and RAM/flash memory card) build that I've started for use with my VIC-20 has several surface mount components, and two of these are capacitors so small that I was afraid I was going to lose them.  It's not an exaggeration to say they could be mistaken for salt crystals.  Perhaps the kit should have provided a spare or two just in case.  ;-)

Here are photos of my work.

What I found most difficult was holding the parts precisely in place while soldering them.  The way I tried was to flow solder onto the pads and then put a little flux on that and place the parts and touch them with the iron, reflowing the solder.  This was hard to do, and especially with the C6 and C7 capacitors.  They are so much smaller than I expected and it was very hard to center the parts over the pads.  Even with tweezers it was a task.  Notice in the photos above C7 is off center, but I checked it carefully with my meter and it seems okay so I decided to go with it.

Maybe pre-tinning the pads was a bad idea because it was hard to make the parts rest completely flat against the board.  Another idea might have been to use solder wick to remove excess solder before placing the parts, and then putting a tiny blob of solder on the tip of the iron and applying it to the capacitor?

So, if I'm going to become good at surface mount work I'm going to need a lot more practice but this project is mostly thru hole work.

Onward and upward!

Gakken Mini Blocks - Blink and You Miss It

I discovered sadly that Gakken made a cute little version of their EX system called Gakken Mini Blocks, but they stopped making them before I noticed.  I think this is so neat.  I blogged about my love of the Gakken Denshi Blocks a long time back.  See http://microcomputing.blogspot.com/2007/

Some people are selling these on ebay, but they are discontinued.  :-(  Too bad.

Here is a photo.

I also found a link to a video about it.  The presenter explains the product and assembles a simple computer circuit.

Soldering my way to Israel

Patrick Alessi wasn't just interested in the software business. He was an electrical engineer. There was a company up in Wilmington, Massachusetts called Cryovac. They made machines that shrinkwrapped fruit, and presumably other things too. Mr Alessi had managed to win a bid on some business to provide them with electronic controller boards for their machines. There were two different boards, and he offered me a chance to make some money assembling and soldering them together. It's amazing to me how I was able to memorize where hundreds of parts should be inserted and soldered into place. The more I worked the faster I got and the more money I made.

In my junior year of high school I had met a very sweet girl who was a foreign exchange student from Israel. Her name was Michal Zilberman. I began to spend a lot of time with her and we became very close. When she went back home we wrote back and forth a few times and I called her on the phone once in a while. I decided to visit her the following year.

I would pay for the trip by assembling circuitboards for Mr. Alessi. It only took me a few weeks to earn the $850 or so dollars I needed for the plane ticket. When my folks noticed what I was doing and that I had obtained a passport they figured I wasn't ready to be a world traveler (probably true) and they sent my grandfather with me. He had always wanted to go to see the Holy Lands, so he was eager to go. When we got to Tel Aviv we didn't actually see each other very much. He was a great traveling companion and we did enjoy some time together and he let me beat him at checkers. When he took off to go on tours including a diversion to Egypt, I enjoyed exploring Tel Aviv with my camera in the mornings and then I would walk to Michal's home and see her family. We spent a few days together in Tel Aviv seeing the city. The we went to stay with her sister in Jerusalem for a few days and spent a day in Haifa.

My relationship with Michal was not meant to be, but this was an unforgettable adventure.

Soldering, and joysticks

Some of the time I spent working with Mr. Alessi was actually spent just playing around. I didn't always write business software. Sometimes I would write code to draw graphics, or read BYTE magazines, or play video games on the computer.

Some of these games allowed the use of a joystick, which we didn't have. I decided to build my own. The Apple II+ supports the reading of 2 variable resistor (volume control) knobs. Many joysticks use this to provide x/y positioning.

To plug a joystick into the computer, the joystick needs to have a 16 pin DIP connector. I went to Radio Shack and bought the connector, a cable, and the joystick module preassembled. I had an old radio control car, so I took the steering controller and cut out a hole where the steering wheel was. It had button for reverse, so I used that for button 1 on the joystick. I can't remember if I added a second button. I guess I must have since it would be hard to play games without it.

The joystick came together easily with my limited soldering skills, and it worked! Thinking back on it, Mr. Alessi was remarkably okay with my plugging in a homebrew device like this into his $2400 computer. The only thing about the joystick was that the value of the potentiometers was slightly off. I didn't get the complete range of motion of a properly designed joystick. However it was good enough to play Choplifter and some other games!

Microcomputer Trainer

I think one of the best things a budding programmer can do is program in machine code. The absolute easiest way to get your toes wet in this skill is by using a microprocessor trainer. Radio Shack used to sell the simplest trainer I've ever seen, and I even have one of these around the house somewhere. Sometimes you can still get these on ebay (in fact that's where I got mine).  

I know this looks like a toy, and it is. For a toy it's serious business. It has a very simple Texas Instruments microprocessor and you program it in machine code using the hex pad. Easy instructions are included. 

https://www.old-computers.com/museum/computer.asp?c=1053&st=1

Once you've played with one of these, the next fun thing to do is to write a simulator in BASIC. Not that hard to do actually. ;-)

Electronic Flip-Flop

Early users of computers were usually also interested in electronics, and in fact I was a casual student of electronics before I knew what a computer is. So I owned a couple of electronic experimenter's labs (and I still do) that we picked up at the You-Do-It Electronics store.

Particularly interesting was the Gakken Denshi Block system, recently reintroduced to the market. This is a high quality kit with a portable radio style case. It has a transparent lid which you open to place pluggable modules.

Here is a photo of my own kit (rebranded as Skilcraft).

One of the experiments was important to my understanding of computers. It was titled Bistable Circuit with Two Lamp. This was another was of saying Flip-Flop, which is a critical building block of digital computers. Up until this point I had only an abstract concept of how a Flip-Flop actually worked.

Here is a link to an article on Wikipedia explaining what a Flip-Flop is http://en.wikipedia.org/wiki/Flip-flop_%28electronics%29

Soldering and machine code

I should probably interject here that a year or so before I really got into programming my brother Neil bought me a kit radio for my birthday. It was a small battery powered AM radio, which did not look like a kit at all when completed. It could easily have passed for a commercial offering you would buy at a department store.

This kit was great fun to put together, and it helped me learn how to solder. I would use this skill as I got older for many purposes, some of them computer related.

I wish there was more of a kit culture today. While you can build robots with Lego Mindstorms and similar systems, it makes sense to learn things as fundamentally as possible.

In a similar way people studying computers should consider learning at least a simple machine code. For example before I had any opportunity to program in machine code I read a book on Z80 machine code. Eventually I had some chance to write 6502 assembly. I never mastered assembly language but it was valuable experience. I suspect that many young people studying computer science today are not exposed to the bare hardware of the machine these days. Universities should be held to account for this IMHO.

Bad Cable

One day while I was hanging around at NEECO a man came in who needed a custom video cable for his VIC-20. The exact specification escapes me now, but the store didn't have what he needed. I volunteered to run down the street to You-Do-It Electronics and buy what we needed to make the cable. When I got back we tried to put the cable together, but no matter what we did the results were terrible. Creating video cables is not as simple as it would seem.

Heathkit

Since our father is an electrical engineer he would sometimes build electronic devices. He had built a very nice stereo receiver from a kit he bought at Heathkit. My brothers and I enjoyed reading through the Heathkit catalogs that would arrive in the mail.

There were many different kinds of computers that could be bought from Heathkit at that time including the H-8, the H-11 and the microprocessor trainer ET-3400 which had a breadboarding area, could be programmed in machine code and could also be expanded to drive a terminal and be programmed in BASIC.

We spent a lot of time fantasizing about these and other machines, but we never got to see one in person. Computers were too expensive for kids with paper routes. Of course that would all change very soon.

Apple Hacker Extraordinaire

In my early teen years I met a fellow a couple of years older than me at NEECO. His name is Richard Stoddart. We hit it off pretty well and I began visiting him at home every couple of weeks. He had an Apple II+ in his basement and he was always doing something interesting with it.

Richard was smart, and he was always very nice to me and this mattered quite a lot since I wasn't exactly a popular kid. Richard taught me a lot about Apple computers, and we had a lot of fun playing games. He was also very active in his Boy Scout troop and was working on Eagle Scout. My mother called his mother and they became friends.

One interesting thing about Richard also was that he was into electronics and was the sort of person who wasn't afraid to modify his computer.

After I hadn't seen Richard for some years I tracked him down after I got married. I was glad to see he was doing well, but now I don't know where he is. I hope you're doing fine Richard wherever you are!

NEECO, a computer store

In the late seventees a computer store named NEECO moved from Springfield, MA to Needham, MA where I lived. I'm sure it was my brother Ernie who first brought me to the store. It was at least a two mile walk from our house, but we were in the habit of walking farther than that just to go to You-Do-It Electronics on the edge of town, so this was really nothing to us.

NEECO was to become a central influence in my life for a couple of years. What a store it was. I have many memories of the place.

When I first started visiting the store there were the following models I can remember:

• Apple II
• Commodore PET and CBM 8032
• Intertec Superbrain
• Hewlett Packard HP-85
• Atari 800 and 400

There was usually something fun running on each machine, especially the Apple and Atari computers. They also had a magazine rack and lots of software for sale.

I spent a lot of time there. Sometimes I was helpful to the people running the store, but I think they sometimes wish I was somewhere else. I owe them a debt of gratitude at least. ;-)

Radio Shack

In 1977 I was ten years old and I was learning about transistors, resistors, Ohm's Law, reactive inductance and stuff like that from my father. I used to go to Radio Shack a lot after school and poke around. They always had a bargain bin box which always had odd things like computer keyboards, and other stuff that seemed good for making computers. Their catalog also listed things like this.

I had no idea of course how to do anything with these kinds of electronic parts, but it was very intriguing. I wasn't sure yet what a computer was, but I knew just a little bit. My life was about to get interesting.

My first scientific calculator

My father is an electrical engineer, and when I was a kid I wanted to be one also. Along the way I decided that I should have a scientific calculator, so for a Christmas present my parents bought me a TI-30 calculator http://en.wikipedia.org/wiki/TI-30.

The original TI-30 was bulky compared to TI-30 derived LCD calculators you can buy today. It was wedge shaped (like a sports car) and had a red LED display. Mine came with a blue denim pattern zip case.

The calculator was fun to use. When you used an advanced math function it spun a digit around in the display to indicate it was thinking.

Probably the best part of the calculator wasn't the calculator at all, but The Great International Math on Keys Book (yes, that really is the title) that came with it. This was a really fun book full of interesting things to do with a pocket calculator.

So, this isn't really a microcomputer but it makes sense for me to start my journey with the TI-30.