LCSI Sprite Card

Next in my ongoing effort to document the world’s most expensive version of Logo for the Apple II, LCSI’s Sprite Logo for the Apple II Family, I show the included hardware sprite card.

The board is a custom design from LCSI based on the TI TMS9918A video display processor, a video chip used in several personal computers contemporary with the Apple II.  Most of the board area consists of the standard TMS9918A chip and support circuits, including 16 KB of video memory (U1 – U8), the video clock, and the composite out.

A short pigtail brings the composite video connection to the outside of the computer case.  The sprite card does not display normal Apple II video, and the user must switch the cable between the sprite card and normal video output when switching between software designed for the card and other software.  There’s a separate ground lead from the composite connector to the power supply.  I’ve never seen a similar separate ground lead on any other peripheral card.  Perhaps LCSI had trouble passing the FCC tests and added this ground as the least expensive fix.

This card includes a 2 KB EPROM.  A ROM (or EPROM) allows reliable software detection of the card.  However, 2 KB is too large for this function alone.  Since the 64 KB main memory of the Apple II is limiting for Logo, I expect the designers used the extra space for Logo-related code or data.  I’ll examine the contents in a later post.  There’s a second unpopulated (U14) ROM footprint.  Perhaps LCSI considered using lower density EPROMs or more EPROM.

The decoupling capacitors (C1 – C10) are too large for the PCB footprints.  Notice how the leads are bent at odd angles to make the available parts fit.

There are two unplated holes (one near C13 and another near U1) in the PCB.  I have no idea why these exists.  Perhaps they’re mounting holes used during manufacturing, or perhaps they’re harmless errors in the board design.

I look forward to seeing the card “in action.”

Mold Making and Casting

I joined the Mold Making class with the Central Oregon Makers last week.  Before going, I had no idea how to make a mold or what I might use it for.  Although 3D printing (“additive manufacturing”) gets most of the attention, mold making and casting seem like useful and versatile tools for duplicating and fabricating items.  I could see using this technique to repair or replace small latches, wheels, key caps, housings, and decorative features where an original is available.  For example, I’ve had trouble finding robot wheels I like, but now I can make my own.

It’s nice to have another tool in my toolbox, and I expect to invent problems just to use this tool.


Play-i is an interesting start-up using robotics to teach programming concepts to children as young as 5 years old.  From the company’s marketing material, here’s the vision:

“In starting Play-i, we set out to create the product we want our children to have. Our mission to make computer programming accessible for every child is bigger than we are.

We need to re-think education. Students are becoming great at retaining facts, but there’s not enough focus on teaching them how to think. We are preparing our children… and your children for the future by inspiring curiosity and igniting a love for learning.”

Details on their system are a bit scarce, but I find their effort fascinating because:

  1. Play-i is designed for young children.  Most commercial robots, even those advertised for education, are unsuitable for younger children.  The robots require assembly, are relatively fragile, and have exposed electronics.  Of course, older or more experienced folks might prefer these things, but the system seems to have sufficient capabilities for both beginner and more advanced learning.
  2. Programming is hands-on and eye-level.  Many other robots require a desktop computer, cables, and software installation.  In contrast, Play-i promises programming with a tablet while sitting on the floor next to the robot.  Hopefully, this system will provide immediate feedback, gratification, and interaction.  The robot will support several programming languages, which should allow the robot to grow and teach a wide variety of skills and ages.  I think the success of the robot will depend on the supporting software, programming interfaces, and curriculum.
  3. The robots have “personalities” and names.  The stories, colors, and shapes associated the robots seem to build an emotional relationship between humans and their robot pets, and I suspect that children will find this anthropomorphism appealing.

I do have some concerns but none ought to block their goals.  Specifically, the hardware is closed and lacks a supported way to “hack the hardware.”  There is an interface for add-ons, but the add-ons appear to be cosmetic or mechanical like an arm, handle, or cape.  I think the closed hardware design is necessary for young children but might limit some types of exploration.

Play-i does promise a developer API, which will likely be key to building a rich, capable software infrastructure and curriculum around the physical robot.  The robot appears to offer quite a bit of capability and flexibility with multiple programming interfaces, options for customization, a decent set of sensors, and a decent set of actuators.

At the moment, Play-i is raising funds with pre-orders for a production run in Summer 2014.  I look forward to seeing their “delightful robots” on my floor.

Living Computer Museum

The Living Computer Museum opened October 2012 in Seattle, WA.  Unlike most museums that strive to preserve artifacts how they find them, usually broken and powered off, this museum keeps their machines alive.  They’re in working condition, complete with the strangely beautiful sounds of teletypes, Disk ][ drives, paper tape, and raised-floor cooling.  The museum is the vision of Paul Allen, co-founder of Microsoft.  Allen cut his teeth on PDP minicomputers, and the museum’s collection reflects this but has a growing display of personal computers.  I know little about the PDP series and vintage of machine, but I found the museum irresistibly fascinating and essential for everybody interested in computers.

I visited the museum last year shortly after its opening, and you may read my full report in Juiced.GS (Volume 17, Issue 4).  And, yes, I should’ve posted this a year ago, but I somehow left the post as a draft … in my defense, it’s only a single-bit memory error.