The Indianapolis 500 has come a long way
since its start on Memorial Day, May 30, 1911. The
inaugural event marked the first time a rear-view mirror
was used in a motor race, courtesy of Ray Harroun
on the “Marmon Wasp” for Indianapolis automaker
Marmon. Harroun also was the only driver in the race
who didn’t bring along a mechanic in the passenger
seat. Mechanics in those early races checked the oil
pressure and also served as the rear-view mirror.
Harroun was considered a hazard because of his
newfangled device. These days, multiple rear-view
mirrors are standard fare on all cars and trucks. Cars
in the Indy 500 are no longer two-seaters, but there is
someone looking over the driver’s shoulder—and I’m
not talking about the tiny lipstick cameras mounted in
the cockpit to give ABC and ESPN viewers a gander
at the road ahead.
Rather, I’m referring to the members of the pit crew
who are normally huddled around an array of computer
displays during the race (see the figure). I recently
had a chat with Adam Schaechter, chief engineer for
the AJ Foyt Racing Team, about the electronics under
the hood of the cars (see “The Indianapolis 500 Electronic
Edge”).
One IndyCar is pretty much identical to another
by rule. They use the same Honda engine with an
electronic control unit (ECU) that isn’t tweaked. The
engines are RPM-limited to 10,300 RPM. Even the
transmission and gearshift are the same.
On the other hand, the sensors and telemetry can be
customized. There are many types of information that
every team will want, such as the ECU controller-area
network (CAN) traffic, which provides details about
engine performance and operation. But that’s not all
that the drivers and teams will want to know. Everything
from G-force on the car to the pressure of each
tire will be of interest.
A standard telemetry system uses 64 channels of
data in addition to the gearbox and motor information.
Each team is assigned its own frequency, and the
information is encrypted. Many of these sensors are
standard fare on each car, but these days, it’s easier to
include custom sensors.
OFF-THE-SHELF PARTS IN AN INDYCAR
One of the surprising things that Adam told me
about was his team’s use of off-the-shelf sensors from
outfits like Digi-Key. Development kits make it easy
to check out microcontrollers and sensors such as
temperature sensors and multiaxis accelerometers.
They can be used to detect vibration in components,
providing a real-time, car hardware debug environment.
Some systems are used during the race. Others
are used for design and prior to the race.
The AJ Foyt Racing Team engineers even do their
own printed-circuit board (PCB) design from time
to time. The team is one of the smaller organizations
participating in the Indianapolis 500, so there isn’t a
host of electrical engineers, programmers, and other
specialists around.
But it does show what is possible with enough
interest and drive plus plenty of low-cost chips with
ever-improving performance characteristics. The
trend toward more intelligent digital sensors allows
easier integration.
So is there more? Teams can already add video
cameras and even thermal imaging cameras to the
mix, although that’s normally done during the design
and testing of the cars.
Where are these sensors and what do they do? Well,
teams need to maintain their advantages, so I can’t tell
you what they won’t tell me. Yet some of the sensors
that the AJ Foyt Racing Team uses include microelectromechanical
systems (MEMS) accelerometers,
and you can image what kinds of things these devices
might be used to test.
Part of the challenge with all this information is
sensory overload. Lots of information can be gathered
but not all of it is useful, especially during the
race, when minimal changes can be made. Even the
information gathered now isn’t given directly to the
driver but rather to the tech team in the pits, who
decides what needs to be done. This often involves
longer-term planning during a race to determine how
the car should be loaded, how lean the engine should
run, and so on.
IndyCar drivers still have someone looking out for
them, though it is more like an entire crew. This May,
maybe you’ll hear, “Drivers, start your telemetry.”