building your own may be a lot more fun. It is for me.
This is the area I enjoy the most and I wanted to use
some of the boards we sell at BeginnerElectronics.com,
but also make this article something for more than just our
customers. I wanted to make this into a robot platform that
worked with various electronic control boards. I originally
planned to use one of our Ultimate OEM boards originally
designed by Chuck Hellebuyck of elproducts.com since it
has a common input/output (I/O) pin-out that matches many
similar OEM-style boards. The original Basic Atom OEM
board and the Parallax BASIC Stamp OEM boards share
the same 20-pin header layout. The Ultimate OEM takes that
further by bringing the extra I/O out to the main header to
offer more direct I/O. Each of these OEM modules has their
own options for programming. The Basic Atom OEM module
shown in Figure 2 is the one I chose to use in this project
and is programmable using the BasicMicro.com Basic
compiler that you can download for free from their website.
The Atom OEM software uses the same Basic
language type commands as the Stamp but offers faster
operation and more memory for program and variables.
The Atom has analog-to-digital (A/D) ports built in that
are brought out to the AX0,1,2 and 4 holes at the top of
the board. If I wanted something beyond BASIC, I could
have used the Ultimate OEM module which can be
configured as an Atom or used with a bootloader PIC so it
can be programmed with PICBASIC PRO, a C Compiler or
even assembly language. The Ultimate OEM also has an
in-circuit programming port at the top so you can program
it directly from a PIC programmer. This allows you to use a
blank PIC rather than a bootloader chip. If you are partial to
the BASIC Stamp, then a BS2 OEM will work fine with this
project, as well. The point is they all share the same first 20
pins at their main I/O headers which allows them to share a
common connection footprint.
FIGURE 3. Silkscreen layer.
FIGURE 4. Bottom layer.
FIGURE 5. Top layer.
The OEM docking station also has all the module I/O
pins brought out to three pin connectors, including the
extra pins that the Ultimate OEM has. The three pin
headers have one pin connected to an I/O while the other
two are power and ground. The central power bus line is
actually split into two lines with each connected to a
different power switch. The pins that are within the
silkscreen that says “servo” are the pins that have power
controlled by the servo power switch. The rest are
controlled by the other power switch. This is how you can
shut off the servos and keep power to the electronics.
Many sensors have three pin connectors similar to a
We modified a custom board design originally
developed at elproducts.com to make a base for the OEM
modules to plug into. Because all the OEM modules share
the same first 20 pins, making a common OEM docking
board that will work with any of them is easy. The board
layout is shown in Figures 3, 4, and 5. The board was created
with ExpressPCB free layout software and you can download
this file from the BeginnerElectronics.com website.
The docking station is designed for robotics as it has
separate power inputs for servos and module power. Each
power input also has its own on/off switch so you can
switch off the servo power but still have power applied to
your OEM module. This allows you to program the OEM
module without the possibility of having the servos driving
the robot off your bench. When you are ready to put your
robot on the floor to test it, then you can flip the servo
switch to “on” to let the servos run.
FIGURE 6. Finished
OEM docking station.
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