Hot Lap Operating Instructions - P/N 21701, 21702, 21705, 21706, 21707, 21708
Table of Contents
The Hot Lap system consists of three units:
Transmitter: (Model 21623 or 21628) An infrared flashlight that stands at the side of the track and shines a beam across the track for the entire race.
Receiver: (Model 21611 or 21614) A small metal box that mounts in the car in plain view of and facing the transmitter. Usually mounted to the roll bar.
Display: (Model 21615 or 21618) A box with a large digital readout that mounts in the car in plain view of the driver. The readout shows the lap number and five digits of lap time. It refreshes at the end of each lap and displays for the entire lap. It connects to the receiver with a telephone-type cable, which is supplied. Lap lengths from 5 seconds to 5 minutes can be timed.
The transmitter shines a continuous infrared beam across the track. The beam is cone-shaped and fans out at 15 degrees each side of center, becoming 40 feet in diameter at a 60-foot range. The receiver in the car only needs to see the beam for 0.002 seconds to recognize it as a valid signal. There are two transmitter types available.
Extended Range Transmitter: (Model 21623) With a 60-foot range. Four C-cell batteries power the transmitter and last 60+ hours. Batteries need to be replaced when voltage drops below 5.0 volts total or 1.25 volts per battery.
Double Range Transmitter: (Model 21628) With 120-foot range. A 5-foot cord with battery clips to attach to a 12-volt car or motorcycle battery. This will power the transmitter for many days before recharging is needed. Unclipping the lead from the battery turns it off.
The receiver is a black powder-coated aluminum box that has a red window in one end. There is a "fisheye" lens mounted in the window, designed to intensify and focus the infrared beam. The receiver comes with a V-block for attachment to the roll bar or other points via tie wraps. Two models of receiver are available. Model 21614 is designed for use with and is powered by the 21615 Standard Display.
Model 21611 receiver has provisions for a 9-volt battery to mount inside and is used with the 21618 Small Display. There is a power switch located on the receiver to control the power to the system.
There are two styles of displays available:
Standard Display: (Model 21615) A black plastic box with a 9-volt battery in it that runs both the display and the receiver. The battery will operate the system for approximately 35-40 hours before replacement is required.
Small Display: (Model 21618) A smaller display box for formula cars, go karts, motorcycles and other racing vehicles with limited space in the driver's area. The actual display window is the same size as the Standard Display. The display is used in conjunction with the 21611 receiver, which houses the battery that powers the system.
The transmitter can be mounted on a camera tripod or taped to the pit wall or a light pole. It is tapped for 1/4-20 threads for easy mounting. The tripod is not furnished with the system. Place the transmitter 10-15 feet off trackside in a location where the cars will be running single file. Aim the transmitter across the track. Mount the transmitter solidly so it doesn't wobble. Do not move the transmitter once timing has started, as accuracy depends on the beam being in the same place every time the car passes. The receiver in the car must see the transmitter, so make sure the beam has a clear shot to the car. The car must spend 0.002 seconds in the beam for the receiver to see it. A car moving at 200 mph needs to be in the beam for only 2 1/2 feet to trigger the receiver.
Place only one Hot Lap transmitter on the track to get lap times. All cars can share it. More than one transmitter will give segmented lap times. If you must have a backup transmitter, separate the two by at least 10 feet so that the beams will not overlap.
Using tie wraps, fasten the receiver to the roll bar in the car or mount it in any other location with the red window facing the transmitter. Aim the receiver directly at the transmitter. If the receiver must be mounted behind a panel, mount it close to the surface and cut a 1-inch hole in the material so that the receiver can "see" out. The receiver must be securely mounted to eliminate movement. Should the receiver move, the sensor could be shaded from the transmitter beam and not function properly.
Mount the display in view of the driver. It can be held in place with the included Velcro, or can be screwed or clamped to a bracket. On the 21615 display, the battery is accessible through a door in the back of the unit, so mount it in such a manner that the battery can be changed.
System parts connect together with a custom telephone-type cable, which is supplied with the system. The cable plugs into the bottom of the display and connects to the receiver. If the cable gets damaged or if a longer or shorter one is needed, it can be replaced with another four or six conductor telephone cord having RJ-11 connectors and identical internal wiring. Standard and custom length cables are also available from Longacre.
PLEASE READ THIS IF YOU SUPPLY YOUR OWN CABLE. HOT LAP CABLES ARE WIRED DIFFERENTLY FROM STANDARD PHONE CABLES. BEFORE BUYING A CABLE, HOLD THE TWO CONNECTORS SIDE BY SIDE WITH THE PLASTIC CLIP TOWARD YOU, AND LOOK AT THE COLOR OF THE WIRES. THE COLOR SEQUENCE MUST BE THE SAME ON BOTH ENDS. FOR EXAMPLE: BLACK-RED-GREEN-WHITE. IF THE COLORS ARE REVERSED FROM ONE END OT THE OTHER, REJECT THE CABLE. THE SYSTEM WILL NOT WORK WITH REVERSED WIRES. IT WILL SHORT OUT THE 9-VOLT BATTERY AND THE DISPLAY WILL SHOW 5 SECOND LAPS, OVER AND OVER.
The transmitter is battery operated. Batteries are not furnished with the system. Four 'C' batteries must be installed inside the Model 21623 transmitter. A switch on the side of the box turns on the infrared beam. Since the beam cannot be seen, a red LED shows when the transmitter is on. Turn the transmitter off when not in use to save the batteries. The transmitter will probably be left in place all day, so make sure the batteries are fresh. Average battery life is 60+ hours, depending on make, age, and heat. Only use alkaline batteries. Do not use the rechargeable batteries. The do not produce enough power to run the transmitter in an optimum fashion. Replace batteries when the voltage drops below 5-volts, as the transmitter range starts dropping rapidly.
To install the 'C' batteries: Remove the 4 screws holding the base of the transmitter to the top and remove base. The batteries are mounted on the board and the polarity is marked. Insert batteries in the clips and verify that the batteries are making contact with the terminals. Replace base.
The receiver just sits in the car and waits to see the infrared beam. When it sees the beam for at least 0.002 seconds, it tells the display to increase the lap count by one and show the time elapsed since it last saw the beam. The receiver sends the information to the display over a telephone-style cable.
A switch on the 21615 Standard Display turns it and the attached receiver on and off. If the system includes a 21618 Small Display, the on/off switch is on the 21611 receiver. Turn the unit on in the pits before the event to make sure it is operational. When the display is first powered up and there are no laps in memory, the display will show 8 dashes "--------." This indicates that the display is ready to begin timing. Replace the 9-volt battery if the voltage falls below 7.5 volts, as readings may become inconsistent.
The START and MODE pushbuttons have four functions:
- Review recorded lap times
- Verify system alignment
- Display a free running stopwatch
- Clear the display and memory
These functions are described as follows:
To review recorded times (P1): Hold the MODE button until P1 appears on the display (~2 seconds). Press and release the START button to display lap 01 and its time. The 01 replaces P1 and blinks to indicate the system is reviewing. Use the START button to cycle through the recorded laps. If the START button is held, the user can quickly cycle through all recorded laps.
To verify system alignment (P2): The Cal mode allows the user to verify alignment of the transmitter and receiver. To access this mode, hold the MODE button until P1 appears. Release the MODE button and press it again quickly. P2 replaces P1 on the display. Now press START and CAL---- appears on the display. Aim the transmitter at the receiver and a 0 appears after the last dash. As long as the 0 is there, the receiver is seeing the transmitter. This is useful to check height adjustment or check to see if the range is sufficient. To return to normal operation, press the MODE button. The Cal mode cannot be accessed unless the receiver can see the signal at least once.
To display a free running stopwatch: While driving, press START after the lap signal has been received. The user will see a running stopwatch display of the lap time. The next lap signal will return the display to its normal state. START must be pressed during each lap to see the running stopwatch.
To clear the display and reset the memory: Hold down both START and MODE buttons for 2 seconds. This will clear all laps from memory and reset the display for recording the next timing session. The display will start recording lap times after the next signal is received. It is a good idea to clear the unit on pre-grid just before the start of a race.
When the display unit is first cleared, it shows all dashes (--------) until the first lap signal is received. When the car cuts the beam, the display changes to all zeros (00 0:00:00). This normally would be shown on the pace lap. After the second lap signal is received, and from then on, the display shows the number and time for the lap just completed.
ELECTRICAL NOISE PRECAUTIONS
Race vehicles generate electrical noise. The Hot Lap is designed to operate in this environment, but there are limits to the amount of electrical noise that can be tolerated before it begins to interfere with the system. Go-karts are particularly noisy. This interference is indicated by a confused LCD display. (i.e., random numbers on the display or erratic lap times) If the system operates with the engine off, but fails when the engine is running or runs at certain RPMs, there is probably an interference problem.
Some things that can be done:
- Make sure other instruments (i.e. tachs) are properly grounded.
- Make sure the engine is properly grounded to the chassis. Scrape the ground point to bare metal. Powder coating is an insulator. Make sure you break through this coating when grounding.
- Avoid running the receiver cable near the tach or other instrument wires connected to the coil or magneto.
- Avoid mounting the display or receiver near the coil, magneto, or other instruments that carry high voltage.
- Ground the Hot Lap receiver to the chassis.
- Install radio suppression spark plug wires.
- Install suppressor spark plug cap (go-karts).
It is possible to diagnose and correct minor problems with the Hot Lap system. If there is access to other systems, it's possible to swap components to isolate any problems.
- Display won't turn on
- Check battery and connection.
- Check switch for looseness.
- Model 21618 display, check cable for cuts or crushing.
- Display only records 5-second lap times
- Receiver is in front of transmitter.
- Low or bad battery. Make sure it reads 8 volts or higher.
- Incorrect or bad cable. Check color sequence on cable. Check for cut or crushed cable.
- Transmitter won't turn on
- Check battery power and connections.
- Inspect red LED to see if leads are broken
- Inspect switch for looseness.
- Receiver doesn't register beam
- Check that transmitter is on and has good batteries. For Model 21623 at least 5+ volts total or 1.25 volts per 'C' battery is necessary.
- Verify that the beam is not being blocked.
- Check cable for cuts or crushing
- Limited receiver range
- Verify battery strength.
- Clean receiver and transmitter lens'.
- Rain or flying dirt and dust can shorten range.
- If the infrared beam has to pass through a glass or Lexan window, it may be weakened enough to not be able to trigger the receiver.
- Segmented or multiple lap times per lap
- Check for other transmitters at the track.
- Check that transmitter is not aimed at a wall or sign as the infrared beam can bounce off and give a false reading.
- Confused or erratic display
- Low battery. Check and replace if necessary.
- Interference from electrical noise. See electrical noise precautions for solutions.
Transmitter: Mat'l: black plastic. Size: 5 1/2" W x 3 1/4" H x 2 1/2" D. Weight: ~16 oz with batteries.
Receiver: Mat'l: Black powdercoated aluminum. Size: 5 1/2"W x 3 1/4"H x 1 1/2"D. Weight: 6 oz. Mounting: V-block attach point for cable tie. Views through one end.
Standard Display:(Model 21615) Mat'l: Black plastic. Size: 5 1/2"W x 3 1/4"H x 1 1/4"D. Weight: ~9 oz including 9 volt battery.
Small Display:(Model 21618) Mat'l: Black powdercoated aluminum. Size: 4 3/8"W x 2 1/2"H x 1 1/4"D. Weight: 6 oz. Display requires the use of a 21611 receiver.
System accuracy: 0.002 seconds.
Memory capacity: 60 laps, then accepts no more data until cleared.
Lap times: 5 seconds minimum to 5 minutes maximum.
Longacre warrants the Hot Lap system against defects in materials and workmanship for a period of one year from the date of purchase. During this period, Longacre will repair or replace, at Longacre's discretion, any Hot Lap system or component returned prepaid by the original purchaser, providing it has been determined by Longacre that the unit failed due to defective materials or workmanship.
This warranty excludes the following: 1)Normal wear and tear. 2)Removal or replacement costs. 3)Damage to related components. 4)Cost incurred due to vehicle down time. 5)Shipping costs. 6)Failure due to misuse, abuse, improper installation, and/or unauthorized repairs or modifications, at the sole discretion of Longacre.
Implied warranty - The warranty is in lieu of all other and/or representations, express or implied, including without limitations, warranties of merchantability and fitness for purpose, and all other liabilities including special consequential damages in connection with the sale or use of any Longacre product.