Keyboard Gizmos

July 15th, 2014
parallel keyboard gizmos

parallel keyboard gizmos

Here is a popouri of parallel keyboard projects that I have been involved with designing.

Not shown

  • A simple single chip AVR PS/2 to parallel keyboard adapter that I forgot about when I assembled the items for this picture.
  • At top is:

  • A reproduction Datanetics keyboard
  • At bottom, from left to right…

  • Home etched/prototype PS/2 to parallel keyboard adapter
  • Production PS/2 parallel keyboard adapter configured for Apple 1/Mimeo
  • Production PS/2 parallel keyboard adapter configured for Apple ][. The latest version firmware can also be used with other vintage computers
  • Home made Apple ][ keyboard to Apple 1/Mimeo motherboard dongle with clear switch - based on schematic at Wendel Sander's Apple 1 site
  • Production Vintage Micros Apple ][ keyboard to Apple 1/Mimeo motherboard dongle with clear switch. Similar to home made one
  • Corey Cohen’s parallel keyboard multiplexor. Automatically accepts and switches input from two different parallel keyboards to a single destination motherboard.
  • Not shown are a number of projects that I have started, but not completed (yet)

  • Datanetics replacement using modern components
  • MM5740 replacement using modern micro controller
  • And then there are the projects that never got past investigation stage.

  • ADB bus to parallel adapter
  • PS/2 Apple IIe keyboard adapter
  • It’s really hard to imagine that I have spent so much time mucking with simple parallel ASCII keyboard technology.

    Vintage Micros has Apple 1 motherboard to Apple 2 keyboard dongles available.

    July 13th, 2014

    I helped with the PCB layout for this cute little dongle. It has a clear screen switch, which isn’t normally available on an Apple II keyboard and does the rewiring necessary to connect a stock Apple II keyboard to an Apple 1, Mimeo or other clone. These are not needed for replica 1s, which has the keyboard pinout necessary to work with Apple II keyboards.

    Here is one in action, hooked up between the keyboard and the Mimeo.

    Keyboard Dongle

    Keyboard Dongle

    They are being sold by seller vintagemicros on eBay: ebay listing

    One word of caution – be sure to connect pin 1 of cables to pin 1 on PCBs. If you reverse them, you will probably blow the 7404 on the keyboard’s encoder board.

    One last thing, I connected pin 4 of the keyboard socket to the clear screen input on the Apple 1. Pin 4 is normally not connected on an Apple II keyboard, but if you make the keyboard encoder mod to use the repeat switch as clear screen input as described on Wendell Sander’s site, it will work without any further wiring changes.

    Model Rocket Launch Circuit

    July 5th, 2014

    A few years ago I built a launch controller for Estes type model rockets. This was designed to be powered by a 12 volt battery. I usually use a battery off a riding lawn mower or motorcycle. When I was a kid I used to use a motorcycle battery that had a bad cell to launch model rockets and it worked great.

    complete launch control

    complete launch control

    This controller has two cables that are used to carry power from the battery to the ignitor.

  • A pair of clamps at the end of 10 feet of cable are used to connect to positive and negative terminals of a 12 volt battery.
  • A pair of small alligator clips at the end of 20 feet of cable are used to connect to the rocket engine ignitor
  • launch controller

    launch controller

    This controller has the following features.

  • A 1/4 inch phone jack used as a safety key. With the plug removed from the jack, the power is disconnected from the ignitor circuit.
  • A two color green/red LED – The LED’s red light is lit when power is available from the battery. The LED’s green light is lit when the safety plug is installed and power is available. Since both LEDs are lit when power and safety plug is installed, the resultant light looks yellow.
  • A green LED that lights up when power is available, the safety plug is installed and the ignitor is connected.
  • A red button that will launch the rocket if all LEDs are lit.
  • Now the reason for this post. The last time I used this controller, I did have a rocket launch imediately when I inserted the safety key. The LED that indicates that the ignitor is connected was designed to draw 10 milliamps through the ignitor and that current is flowing when the safety key is inserted. Though I tested that current through a number of ignitors, it must have been enough current to fire the one that went off prematurely. What I have decided to do was to substantially reduce the test current through the ignitor. The easiest way to do this was to use a smaller test current through the ignitor and use a transistor to amplify the current to a level high enough to light the indicator LED.

    Here is modified schematic. By the way, don’t bug me about the LEDs which are shown connected backwards in this drawing.

    launch controller schematics

    launch controller schematics

    With this design the test current through the ignitor can be roughly calculated as:

    12 volts/100000 ohms = 120 micro amps

    I think that this tiny current would be extremely unlikely to launch a rocket inadvertently. I measured the current through the LED as about 30 milliamps. This means the transistor is multipling the current by about 250 times.

    SCELBI 8B update

    July 4th, 2014

    Here is a composite image showing the great progress that has been made on the 4 boards that need to be done for the SCELBI 8B.

    Composite Image of 8B Boards

    Composite Image of 8B Boards

    Still a ton of tweaking and fine tuning needs to happen, but you can almost see the light at the end of the tunnel. I also need to find some time to figure out what I’m going to do for the custom chassis.

    The backplane layout is for all intents and purposes done. The memory expansion card is next closest to complete. I haven’t done much with the PROM card, but I’ll do a complete review of it. The curved traces promise to require a lot of effort to match up to the original. The 4KSRAM cards need a lot of work and since the original has curved traces, it will take an extra effort to finish.

    More on the Sightseeing Sixth Division in World War I

    July 1st, 2014

    In a previous post, I noted how my Grandfather was a member of the Sightseeing Sixth Infantry Division in World War 1. I found a history of the Sixth Infantry in World War 1, written at the end of the war. The history can be downloaded from this site

    Using this history and Google Maps, I created a rough map of where my Grandfather might have travelled. The routes from place to place are not exact, but the general areas where the Sixth travelled up to the end of the war are taken from the history. Travel from the LeHarve to the training facilities around Chateau Villain would have been by the famous 40 men or 8 horse box cars.

    The Sightseeing Sixth Division in France in the Fall of 1918

    The Sightseeing Sixth Division in France in the Fall of 1918

    The other interesting thing that I learned was the extreme lack of transportation that troubled the Sixth Infantry’s movements. Horses were poor cast offs from the French army. Often the men hauled their equipment themselves, instead of relying upon horses or trucks. Once at the front, most travel was on foot. It is interesting that my Grandfather was a truck driver for a unit that apparently had very few trucks. The only mention of type of truck, was a brief mention of usage of some “liberty trucks”.

    I’ll be at the MakerFaire in Dover, NH Aug, 23rd

    July 1st, 2014

    I’ll have a Mimeo (Apple 1 clone) and a SCELBI 8H clone up and running and if you come, you’ll be able to see and operate them.

    MakerFaire Dover Flyer

    I hope to see you there.

    Brain Board Manual Errata

    July 1st, 2014

    I have a mistake in my Brain Board Manual versions 5.3 (current version) and lower. On page BB:12, the last switch settings are incorrect.

    Dual Bank Mode – Either high bank of Brain Board or low bank of Brain Board is selected

    should be:



    Switch 3 and 4 settings are backwards in the manual. When I get a chance I’ll update the PDF that is on my Brain Board web page. I already printed manuals for the remaining inventory of Brain Boards, so will hand edit those manuals.

    2nd “annual” bike to work day was yesterday

    June 26th, 2014

    My last “annual” ride to work day was four years ago.

    Here is how yesterday’s annual event went.

    The sun woke me up at 4:40 AM. – those who don’t live in Eastern New England probably don’t realize that in the summer the sun rises early here. Since I was up, I decided I might as well use the time and take my bike to work. I packed some work clothes, shoes, a towel and my laptop in my panniers. I reviewed my route using google maps, printed directions and headed out the door a little past 5:30AM. I didn’t get lost, even thought the directions are 3 pages long and include something like 40 steps on this years improved 27 mile route. By the time I reached the hills of Littleton and Boxborough, fatigue was starting to set in a little bit. However, I arrived a little after 8:00AM without too much difficulty. Due to the early hour, traffic was light and the weather not a problem.

    During my work day, I checked the weather a few times and saw the temperature reaching over ninety. I figured I’d melt on the way home.

    I left for home around 5:00 PM. Only one wrong turn this time, and I only went about 100 feet before realizing the mistake. While waiting to cross a road, a jogger mentioned that due to the heat, that it was heart attack weather. He was happy to take the break while waiting for the walk light. Though it was in the 80s, the humidity wasn’t too high, so the temperature wasn’t unbearable to me. Also, a tailwind helped me over most of the route. Unlike last time, I didn’t completely bonk. However fatigue was definately a factor for the last few miles. I reached home around 7:30.

    5 hours on the bike and 54 miles is a lot for me in one day. However it is a lot more interesting than a hour on the freeway in the car. Who knows, maybe I’ll get in another “annual” ride to work in, before the summer is over.

    Grandfather Willegal’s Experience in World War 1

    June 20th, 2014

    My Grandfather was a World War 1 veteran. I only talked to him once about his war experiences. He was a truck driver and told me how he used to get those old trucks up to a speed of 60 miles an hour. I also remember him saying that the army in World War 1 was the last good army or something to that effect. I’m not exactly sure why he held that opinion, but he wasn’t bashful about making the claim. My Grandfather also showed me some trench art that he had made out of some cartridge cases. I wish I knew where that trench art was. Hopefully someone in the family got a hold of it, after he passed away.

    Grandpa Willegal - circa 1960

    Grandpa Willegal – circa 1960

    I learned a little bit about my grandfather from my dad. He once told me that Grandfather mentioned that when they were being shelled by the German artillery, that they would take cover in the ditches by the side of the road. I was once visiting Circus World Museum with my dad, and he mentioned that the trucks in the circus train display would be similar to those trucks my Grandfather drove in World War 1. I think the Circus World trucks are Mack AC’s, which were indeed, used in World War 1 by the British and Americans. I don’t know for sure that this is the type of truck he drove, but it’s possible. The Mack AC’s have a rated speed of 18 miles per hour. Another army truck of the time, the famous Liberty Truck, was only supposed to reach 15 miles per hour. I wonder what my Grandfather was doing to get up to 60 miles per hour.

    My sister did some online searches and found a few records, including this certificate of service which she found at the Wisconsin’s Veteran’s Office.

    grandpa Willegal's Certificate of Service

    grandpa Willegal’s Certificate of Service

    It turns out that he was a member of the Sixth Infantry Division. The medal depicted at the top of the certificate is the World War 1 victory medal. He is given credit for participating in Vosges Sector (Aug 31, 1918 – Oct 18, 1918) and the Meuse-Argonne Defensive Sector (November 2-6, 1918). The other interesting thing is how quickly he was moved into the combat zone. He joined the army on May 4th, 1918 and was overseas by July 14, 1918. By August 31st, the 6th Division was on the front lines.

    There is some information on the Sixth Infantry Division in World War 1 at this site. The Sixth Infantry Division site focuses on the World War II, but there are a few tidbits about the Division’s activities in World War 1. The interesting thing is that this brief history mentions how the division was involved in marches that were subject to German artillery fire, just like my grandfather told my father.

    My research on the Sixth Infantry shows that they did a lot of marching, during which time, they picked up the nickname, “The Sightseeing Sixth”. Like most new American divisions, after training they were moved to the relatively quiet Vosges Sector in order to become adapted to actual combat conditions. Here is website with some information about the Vosges Sector. They were in reserve at the end of the war. Apparently they were about to be committed to the Meuse-Argonne offensive, when, rather unexpectedly, the war ended.

    The Meuse-Argonne offensive was a very bloody affair. Who knows, I may not be here, if the war had lasted much longer and the Sixth Infantry ended up being committed to that fight. I plan upon putting together a blog entry comparing the Meuse-Argonne offensive of World War 1, with the biggest American battle of World War II.

    SCELBI 8B Backplane Progress Being Made

    June 10th, 2014

    Lately. I’ve been making some good progress on the 8B backplane. Hopefully in a few more weeks and I’ll have it in good enough shape in order to declare it finished. I’ll probably just go ahead and get it made when it’s ready, even though I have a lot of work to do on the other 8B specific cards.

    There is quite a bit involved in building an 8B chassis and 8B builders can start on the chassis while I finish the rest of the cards. Anyway the CPU can be checked out by jamming in instructions, without memory being present. The front panel, CPU, DBB, and input boards are completely identical to the 8H design and I still have some of those PCBs in stock.

    One thing I’m going to have to think about a bit, is whether to make a batch of SCELBI custom sized chassis or not. A BUD AC413 can be made to work, as it is nearly the correct size, just a 1/2″ short, other dimensions being right on.

    Status of the other 8B specific cards are:

  • memory expansion – I haven’t started on this one, but it is the most basic of the 8B specific cards, so should take the least amount of time to do
  • 4K SRAM- designed to accept 2102 static ram – this card is pretty far along, maybe half done.
  • EPROM – designed to accept 1702 EPROMs – I have a tested, working layout for this card done by someone else. The original layout artist did a good job, but there are a few things I want to change. I will completely go through it to make the layout details match the original as much as possible.