David Buckley - Zeaker

[The name Zeaker was to be a combination of ZX-81 and Seeker but I was influenced by Speaker as well.]

Zeaker was designed to be controlled from a Sinclair ZX-81 fitted with an I/O expansion card with an 8-bit output and 8-bit input I/O port.
At left is the kit, while above is the finished Zeaker. The layout of Zeaker with the four bumper sensors can be seen. The Control Station (top) contained the interface electronics and four C-cell NiCads for power, which could be charged overnight using the ZX-81 power supply. It was connected to the I/O card by two ribbon cables and to Zeaker by a ribbon cable umbilical. Zeaker itself had two drive motors, four bump sensors plates activating six switches (two at the front, one on each side and two at the rear), two LEDs (at the front by 'Zeaker', a speaker and central pen, all of which were under computer control. Just in front of the Umbilical connector can be seen the LED indicating Pen-up and Pen-down.

Prototype - built November 1982
From somewhere (I forget now) I had a Hebot-II for evaluation, (did I write a review?).
Hebot-II was a look-alike for the MIT-turtle and the shell stops half way down the body.
Although the turtle control worked very well the shell was almost useless for detecting obstacles.
It prompted me to make something better.

Technical information

                    Zeaker Control
Write to Zeaker				Read from Zeaker
---------------                         ----------------
byte=0  - Zeaker OFF                    [Port=left, Starboard=right]
                                          low => fender switch closed
WD0=1 - Left motor backwards             RD0 - Starboard aft
WD1=1 - Left motor forwards              RD1 - Starboard side
WD2=1 - Right motor forwards             RD2 - Starboard front
WD3=1 - Right motor backwards            RD3 - Port      front
WD4=1 - Pen Down, activate solenoid      RD4 - Port      side
WD5=1 - LEDs red and green On            RD5 - Port      aft
WD6=1 - Horn low tone                    RD6 - (spare)
WD7=1 - Horn high tone                   RD7 - (spare)

Pin out of READ and WRITE 16 pin DIL plugs from Control Station
---------------------------------------------------------------
     pin
D0  1  16  5v
D1  2  15  5v
D2  3  14
D3  4  13
D4  5  12
D5  6  11
D6  7  10  0v
D7  8   9  0v

Pin out of Zeaker Umbilical
---------------------------
              pin
RD2  \ Front 1   2   RD3  \ Front
RD1   }-Port 3   4   RD4   }-Stbd
RD0  / Aft   5   6   RD5  / Aft
RD6          7   8   RD7
Speaker      9  10   LEDS
Motor Stbd  11  12   Motor Port
Motor 2.5v  13--14   Motor 2.5v    (commoned in Zeaker and in Control Station) 
Solenoid    15  16   0v

Notes
There is no 5v supplied down the umbilical to Zeaker from the Control Station.
On the prototype I used the supply to the LEDs to power a 556 used as a dual comparator to read two opto transistors, one looking down in front of the toe and the other looking out and down in the gap between the two front fenders. Thus if I turned on the LEDs and read D6 and D7 I could use that information to get Zeaker to follow a line or seek light.
[D6 eye ahead, D7 eye down]
Zeaker would now be an ideal robot to control from any of the 24 pin Stamps such as the BS2 Stamp from Parallax Inc., see Links. The two spare lines D6, D7 could even be used to communicate with a serial LCD especially if it was a Scott Edwards type which will read four switches.

2023 July 20
Following on from making Arduino interfaces for Zero2, Zeaker2, BBBC-Buggy and MM3 I made one for Zeaker and so now after over thirty years Zeaker is again under computer control. See the Upgrades page.

Manual
View Manual online (1.97Mb)
Download zipped Manual (1.95Mb)

PCB layouts

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