Some time in the early 90s I was given four wheels and a differential drive mechanism from a toy truck and a steering mechanism from a radio controlled raceing car. Using those nice fat wheels I decided to build Sea-Roller - to drive on the sand-seas of Mars, controlled by a Parallax Stamp-1, the same as the Groundhogs, and use two Infra-Red Proximity sensors, which I had bought in Germany, to detect obstacles.
I replaced the racing car wheels with two of those from the truck and made a wooden chassis and painted it silver, but unfortunately when it came time to make it all work I found one of the proximity sensors was faulty and there was no where I could buy a replacement! Due to work and domestic circumstances Sea-roller was put in a bag in a cupboard and forgotten.
However in December 2025 I was searching on the web and one of the pages that came up was from Temu and on the page were sensors that looked just like those I had used for Sea-Roller thirty years ago. I got out and checked Sea-Roller and the sensors were the identical ones - same part number, everything!!! So I bought two just in case there was a difference. When they arrived there was a slight difference, the new case was fractionaly shorter.
So now Sea-Roller is complete with its new sensors. The software is modified from the Groundhogs to suit the different sensors and steering method.
- The steering mechanism has an electric motor to turn the wheels and a potentiometer so the controller can tell the angle of the wheels.
- The IR-Proximity detectors (E18-D80NK IR Sensor) are adjustable for range by a multiturn pot in the end of the sensor and when an object is detected the outut goes low, and they can be aimed by moving the friction swivels.
- In parallel with the IR-Proximity detectors are LDR eyes, read by the Pot command in Stamp Basic. If an object is detected the Pot reading goes to zero. The eyes can be aimed by bending their mounting wires.
- The two motors are driven by a modern H-bridge because I must have used the original for something else.
- Above the steering mechanism is a speaker just visible in photo #10.
- At the rear there is a coax connector for external power and a relay automatically changes over from the battery to external power.
- The Parallax Stamp-1 is on the rear board plugged into the bus and the front board is just buffered LEDs on the bus.
- The square-pad circuit board was one from Tandy/Archer that had nice copper fingers at one end which made mounting the LDRs easy.
