Trouble Shooting an AIM IR Beacon Transmitter

Getting an accurate lap time is a must for any serious go kart racer, but finding the most accurate devices for an affordable price is not easy.

The most accurate devices are lap timers, like the MyChron1 with inductive tachometer. This lap timer still had an IR transmitter in a black ABS housing with 16-way – coding options, so that each MyChron1 user was able to set his own "signal set" without disturbing others or being disturbed by them. Yet soon we had to recognize that 16 settings are not enough, we would have needed hundreds or even thousands of them.

Different Types of Lap Timing:
  • Manual Timing: The driver presses a push button when passing a certain point of the track, e.g. at the finish line. This is not very accurate and is often forgotten in the heat of the moment.
  • Lap timing using an infrared beacon: This is the most common method because it is inexpensive, accurate, reliable and widely applicable. Place the ONE IR Transmitter at the edge of the track which sends a coded infrared light signal. "Coded" means that the light-on and light-off phases, pulse times and intervals are precisely defined. In order not to be disturbed by transmitters from other manufacturers or to disturb transmitters from other manufacturers every manufacturer has its own frequencies.
  • Lap timers using manual release: The error of measurement in IR lies, when it is correctly installed and used, at the third decimal place, i.e. in the range of milliseconds (1ms = 1 / 1000 s). But it is somewhat inconvenient to handle the transmitter, because if you forget it on the pit wall it's gone as everybody can use it. It also requires electricity – i.e. maintenance.
  • Lap timing via magnetic strip: There is one (or more for split times) permanent magnetic strips across the track as trigger and a magnetic field sensor passes over. Almost all go-kart tracks in Europe are equipped with magnetic loops, but nearly all automotive and motorcycle racing tracks (except of Hockenheim and some tracks in France and Spain) are not equipped with it. Lap timing by a magnetic strip is extremely accurate, reliable, convenient and cheap, but for motorcycles it is not very practical (as opposed to racing cars and karts) because of the large ground clearance and related mounting deficits. Lap timing via GPS: They are very convenient because they do not require a transmitter. You go with the lap timer to the finish line and "set" the measure point. The problem of the cheap GPS lap timer is the low sampling rate: there are devices that only detect the position of the device on earth once a second. And because each measurement has a tolerance of less than + / - one measurement cycle these lap timers are only good for hikers with orientation problems. Each of these methods has advantages and disadvantages and requires certain procedures to ensure the reliable operation of the system.
Issues and Set Up of Timing Devices:
  • The magnetic field sensor is completely foolproof, but you can forget to press the manual trigger. The most things can go wrong when using infrared measurement. The signal of the IR transmitter is a clocked infrared light, for example – OFF – ON – OFF – ON – OFF – pause – ON – OFF – ON – OFF – ON – OFF – pause, etc. The times of these cycles are definitely set by each manufacturer. Lap timers User Manual Release It is from the emitter diode in the form of a light cone with 18° spread continuously sent, and once it is seen IR receiver of the display will show the lap time. That is, the further the transmitter is removed, the greater is the area where the signal can be detected. This also means that the further one passes the transmitter, the less important is the height of the receiver. Furthermore the further one goes by the transmitter, the sooner you go into the light cone. To get earlier in the light cone one can turn the transmitter on the pit wall by 9 ° in the direction of the turn. Then the kart travels always at the same point in the light cone, regardless of the distance to the transmitter. The closer one goes by the transmitter, the shorter the time that the receiver has to detect the signal. At 10 m distance and height are the best 3.17 m. At 252 km / h shall be back 70 feet per second, at 252 km / h takes you through the 3.17 m wide cone in 0.022 s. Therefore, the receiver must have a clear view to the transmitter. Of course, the more transmitters are set up, the stronger the signal, and the more reliable the system works.
  • Warning on the transmitter: If two transmitters send signals, perhaps even from the same manufacturer, it could look like this: The receiver now ignores what he sees there, because that's not his signal. This effect is independent from which manufacturers the transmitters are coming from, because each manufacturer has a different signal code. The cone has at 20 m distance a diameter of 6.23 m, which means that in this case, the distance from one to the other transmitters must be at least 6.23 m to ensure the reliability of operation. For "security" reasons 10m should be adhered as there are transmitters with larger viewing angle. An occasionally occurring phenomenon is the picket fence effect: when the sun is low and you drive past a fence or trees and the solar radiation interrupts the corresponding Lap timers User Manual Release frequency in the IR receiver a lap time might be triggered.
  • The powering transmitter can be done via 8 AA batteries at 1.5 V in normal mode (range with fresh batteries approx 15m). We recommend at distances of more than 10 m to change to high power mode (range 30 m). In this state an external 12V battery is needed. Lap timers are powered by a 3V button cell CR 2430 battery. To prevent that batteries "stand out" because of vibrations and crushes and the lap timer therefore turns off you should (when having this problem) put foam rubber in the cavity. GPS devices: there are two or three things that need to be considered when installing the antenna. Furthermore one need to consider the cold start procedure during which the device searches 1-2 minutes for satellite signal while the car is standing still. The GPS module stores the distance data (measuring points for laps and split times) and recognizes on the basis of the coordinates stored in the Lap timer on which track you are. Ho
  • Lap Timer needs a fixed point on the track where it can be trigged accurately and reliably lap by lap.