Laser 3 Manual Page

Installation and operating manual

Manual Version 3c Sept 2000. Specification subject to change
Radio remote version
[Installation] [Fit to Vehicle] [Calibration] [Operation] [Connections] [Fitting Sensor] [Remote]
Introduction (Updated Jan 2002)  
The Brantz Laser 3 Rally Computer is a sophisticated high precision instrument which shows via red LED readouts Time of Day including hundredths of a second and has two stopwatches. Six digit distance (to three decimal places) is viewed via shiftable four digit windows. Speed information includes current, maximum and average speeds. A leap forward in technology allows optimisation of car performance tuning using the acceleration figures to 60, 100 and 120 mph and kph from 0, 30, 50 and 70 mph and kph, rolling start times e.g. 30-70 along with times for a standing start quarter mile or kilometre, and a standing start mile or kilometre. A programmable digital fuel gauge is provided which will read a gauge which stands unpowered, or is already part of a vehicle's electrical system. Options include two versions of wireless remote control units for zeroing etc, one version of which has a screen of its' own which also permits its' use as a wireless repeater unit which can be fitted for the driver so that he can monitor speed, distance, fuel etc, and there is also a data collection port on the Pro remote which can pass computed information periodically to a PC to enable a stage to be stored & analysed.
A minimum system for fitting to a road vehicle is the Laser 3 computer plus a distance sensor with its' connectors and fasteners. The computer and sensor should be tested before being fitted to the vehicle as follows: Open the rear connection cover door of the Laser and note the three connection blocks. Take great care not to connect anything to the wrong terminal or damage will occur. The top block is marked 'Fuel Gauge FF' terminal. Do not connect anything to this yet. The centre block is for the distance sensor only and connections will be made to this later on. The lower block is for the 12 volts power input. Use good quality wire and connect the + terminal of a 12 volt battery to the terminal marked ++12v on the computer. The spring loaded type terminals will allow a stripped end of wire to be pushed into the block if the gripper is depressed with a screwdriver etc. Releasing the gripper will clamp and connect the inserted wire which would preferably be solder 'tinned' to prevent stray strands of wire from moving about. Connect terminal marked 12v-- on the computer to -12volt terminal of a charged battery. For safety, connect computer first, battery last. Pressing the button marked ON should cause the readouts to light up. You can set the clock if you wish, as directed in the instructions later. The clock's backup battery will be charged during the first period of use. Disconnect the computer from the battery. Connect up the distance sensor to the centre terminal block as directed in the sheet for sensors. Re-connect the computer to power and set the four calibration switches to 1000 and turn the computer ON. Spin the sensor internals or if a wheel type sensor is provided, touch the end of the sensor many times with a metallic object such as a screwdriver. The lower readout should increment. The above test shows that the computer and sensor are working ok.
Fitting to the Vehicle (Fitting the sensor)

Using a good quality 2 ampere mains cable, connect long insulated wires to the block terminal of the computer as in the previous section. Take care that there are no loose strands of wire left out of the connectors. Make sure you can distinguish which wires are for the sensor (screened wire is best) and which wires are for the 12 volts power input. Cut out the block connector cover plate to let in these wires, leaving a minimum of clearance so that dust does not get in, and replace the cover plate. The computer can be mounted into the vehicle using Velcro type self-adhesive strip, which reduces the amount of vibration passed from the vehicle to the computer, or 5mm threaded screws into the corner mount holes. Connect up to the distance sensor as directed in the wiring table at the back of the manual to the centre block which is marked Sensor ONLY. Terminal ++ is a 5 volt power feed going OUT to the sensor. Most 2 wire sensors do not need connection to this terminal. PP is the positive pulse INPUT terminal and -- is negative out to the sensor. Connecting PP to -- in test pulses simulates the action of the sensor. Connect the power leads to the vehicle's battery terminals directly via a 1.5 amp fuse. Note that reliable service cannot be expected if poor quality connections are used . Carefully observe the correct polarity of positive and negative. It is assumed that the fuel tank sender has one end connected to negative ground. The other end may or may not be disconnected from the rest of the vehicle and is connected to the upper Laser block connector FF. If a second auxiliary fuel gauge is required (say in the rear for filling purposes) then connect / disconnect it via a switch when actually used as it can affect accuracy.

All speed and distance functions rely on the computer being accurately calibrated for the vehicle/gearing/tyre combinations pertaining. Set the 'Calibration' switches to 0000. As soon as the vehicle moves the total readout will change to 'Cal Set'. Go to the start of a measured mile. Press the 'Zero lower' button momentarily. Drive the measured mile exactly and stop. A figure will appear in the lower 'Trip' readout. Enter this figure onto the Calibration switches. Turn the vehicle round and check that the measured mile measures as a mile on the computer when driven. The computer is calibrated in kilometres exactly as above, but substitute the word 'kilometre' for the word 'mile'. Note that when the computer is calibrated in miles, all speeds will be in mph and when calibrated in kilometres, all speeds will be in kph. Note the different calibration figures if different gears/wheels/tyres etc are to be fitted during an event.
Keyboard convention: Green keys are normally selected. Holding the 'Select Orange Keys' button down whilst pressing other buttons will select the functions described in the orange text areas. The computer is turned ON by pressing the 'ON' button. To turn OFF hold the 'Select Orange Keys' and 'OFF' button until the displays disappear. The 'Select Orange Keys' button locks itself in for about half a second, so sequential button pushes can be made (eg 'Sel Orange then 'OFF' in quick succession).
Dimming the Readout  
The first two stages of the 'off' control lower the intensity of the readouts. Release the 'OFF' button at the stage when the readout says 'LO'. Full brightness is restored by pressing just the 'ON' button. When the 'Off' button is used to go to the fully off situation, all the tripmeter modes which were in use at the time of switching off are remembered for the next time the computer is switched on again.
Set the Clock  
Press 'Resume Time' if the top readout is showing fuel. Press 'Select Edit Item' repeatedly until the 'Set-ti' item is offered for modification, then press 'Orange/Modify Item' to enter the time setting menu. Using the numeric keys, enter each of the six digits of the time in 24 hour format. As soon as the sixth digit is entered, the clock exits the setting mode. If a mistake has been made during setting, either complete the six digits and then do it again correctly, or press the 'escape' button which then ignores the mistaken attempt. Note that the last two digits of the clock (hundredths of a second) do not normally show as they change too quickly to be of any value in real time. These show only when the clock is frozen by the 'Hold Time' button.
Default Settings  
This button restarts the computer if an electrical problem has caused the internal processor to 'crash'. It is a powerful command which will lose most data stored, so do not use it unless there is a major problem. The Laser 3 copes with severe abnormalities in the car's electrical system, so if it has become necessary to use this command the car must be giving trouble and is in need of close attention.
Distance Mode  
The 'Total' and 'Trip' readouts are identical except that the Trip readout does not have the 'Hold' function. The 'Hold' function takes a spot distance reading where the readout does not change, but the distance is still being calculated inside the computer. This function would be useful for pace-noting when a distance to a feature was required to be noted, but the vehicle could not stop. When on 'Hold' the green light in the button will come on. Another press of this button will restore the readout to the current position as if the button had never been pressed. The 'Freeze' buttons will stop the readouts from counting (the button lights) if pressed, and will restore counting if pressed again. The distances are computed in six digit format e.g. 123.456 miles or km, but the readouts only view four of these digits. The digits on view can be shifted along by repeated presses of the 'Mode Distance' button. The distance readouts can be preset to any distance required either whilst the vehicle is standing still or whilst it is on the move. Press 'Split' at the point where the new distance is correct. Enter the six figure distance using the numeric keypad. As the sixth digit is pressed the computer leaves the 'Split' mode. If the vehicle has been standing still during the preset or the readout is in 'Freeze' mode, then that figure will come up on the readout, and if the vehicle has been moving, then the distance moved during the presetting process will be added to the preset distance. If the tripmeter is in '-dist' mode, ie counting downwards, then the distance traveled since the 'Split' button was pressed will be deducted from the set distance figure. the 'Split' facility is available on both the upper and lower readouts. In the 'Split' mode it is not necessary to enter all six distance digits; the unentered digits following the entered digits will be assumed to be zeros. If entering less than six digits, pressing the 'Return' button indicates to the tripmeter that the "Split' figure is complete. If a mistake is made during the entering of the 'Split' figure, a press of the 'escape' button will ignore the mistaken attempt and allow another entry. A mistake in entering a 'Split' figure can be corrected by moving back to the incorrect digit by use of the 'Down Arrow' button and re-typing the correct digit. The 'Zero' buttons reset the readouts back to zero, but note that to prevent inadvertent zeroing of the upper 'Total' distance readout, the upper zero button needs to be pressed for three seconds to work. Pressing the '-DIST' button reverses the count. The button lights when counting downwards. Pressing the '-DIST' button again restores count to the upwards direction. The RR terminal on the upper connector in the rear of the computer can be configured by 'Select Edit Item' as a Reverse instruction (RR setup = -dist) and can be connected to reversing lights; -12v signals a reversal (use a relay if the vehicle's logic is the opposite of this) , or the 'RR' Terminal can be configured to accept a hard wired remote zeroing button for the lower readout (-12 volts = zero readout, see below for wiring. Configure RR setup in the 'Select Edit Item' menu as REMOTE-tp).
Speed Mode  
Puts the current speed on the readout. Available in both the 'Total' and 'Trip' readouts.
Max Speed Mode  
Available in the 'Total' readout. The maximum speed attained since the computer was last switched on, or the 'Zero Upper' button was pressed in this mode which resets the maximum speed monitor.
Average Speed Mode  
Available in the 'Total' readout. Calculated for up to 24 hours, since the computer was switched ON, or the 'Zero Upper' button was pressed in this average speed mode which resets the calculation to re-commence from that moment onwards for up to 24 hours. Average is calculated to one decimal place.
Acceleration Mode  
Entering this mode clears some other calculations and memories from the computer, and is intended to be used during vehicle testing etc, outside the rally competition. The acceleration facility enables vehicle modifications to be assessed for their value. Press 'Mode Accel' and use the 'Select Edit Item ' button to choose the speed range (start and end) over which the time is to be measured. When the required acceleration parameter is showing (eg 0-60 or standing start 0.25 etc) press the Orange/ Modify Item. The time in seconds (with decimal place) will show in the 'Trip' readout. The run can be repeated by pressing the 'Zero Lower' button. Pressing the 'Resume Time' button quits the Acceleration Mode and restores the readouts to previous settings.
Fuel Mode  
To show the tank contents Press 'Mode Fuel'. The fuel gauge map can be programmed by emptying the tank to the level you wish to call EMPTY. Ensure that the vehicle's fuel gauge system is powered up if the Laser 3 is to run alongside the original. Normally this is achieved by having the vehicle ignition turned on. With 'Select Edit Item ' button select 'cal-fuel' and press 'Orange/Modify Item'. The computer will spend about a second detecting if you are attached to a volts-on or volts-off type system, then it will show 'SET-E' and a figure. Press 'Orange/Modify Item' and this empty reading will be programmed into the computer memory. Press 'Select Edit Item' and the menu will move on to offer you the quantity of fuel. Fill the tank and note the quantity in litres. Use the Laser 3's up or down arrows to match this quantity figure then press the 'Return' symbol on the keypad. Press the 'Orange/Modify item' button to put the fuel guage level (at this quantity of fuel) into memory. Quit the calibration sequence by pressing 'Resume Time'. The computer assumes linearity of the gauge. The quality of the sensor in the tank dictates the precision of spot readings. The Laser 3 is capable of measuring litres to one decimal place. Once programmed, the map is retained by the computer even when it is switched OFF.
Timing Functions  

1/Time of Day: Normally, six digits show on the 'Time' readout. Pressing 'Hold Time' halts the readout and displays the hundredths of a second. 'Resume Time' restores the clock as if nothing had been pressed. 2/Stopwatches: The 'Total' readout and the 'Trip' readout each have a stopwatch available. The full range of Freeze/Hold/Zero buttons are available for the stopwatch whilst the accompanying readout is in stopwatch mode. The stopwatches count in minutes (rotating at 60) and seconds. A fast press of the zero button commences counting. Another fast press stops the stopwatch. A press of more than three seconds zero's the readout. If both readouts are in stopwatch mode, and one stopwatch is waiting at zero, pressing the 'Freeze' on the other stopwatch will freeze that stopwatch and simultaneously commence the zeroed stopwatch counting. An option available via the 'Select Edit Item' enables 'Auto Start' of the upper stopwatch as soon as the vehicle moves off from rest. This happens only if the stopwatch is at zero, and is useful for stage starts. Stage start and stage finish functions are best done using the 'Total' readout as stopwatch by pressing the remote button which stops the stopwatch and the time of day together at the stage finish. Stage start can be done manually with the remote button or automatically using the 'Auto Run' self-start.

Auto Off  
Used to power the Laser 3 down when the vehicle is parked. It is enabled or disabled from the 'Select Edit Item' menu which monitors the motion of the vehicle. If no motion is detected for 15 minutes when the computer is in 'Auto Off Enabled' mode then the computer readouts are shut down and memorized. As soon as the 'ON' button is pressed or the vehicle moves, the readouts are illuminated. Standby current is around 15 milliamps, so disconnect the Laser 3 if the vehicle is to be parked up for more than a week.
Block connectors as viewed from the rear of the tripmeter.


Fuel Gauge FF

RR Input (Configure as Reverse/R.Zero)

Sensor++ (+5V out)

Sensor PP (pulses in)

Sensor -- (negative out)


Power in +12Volts

Power in -12Volts

Centre Connection Block is wired for each sensor as is shown in columns Sensor Connects to ++ terminal as in the chart Sensor connects to PP terminal as in the chart Sensor connects to -- terminal as in the chart
Universal speedometer cable (black plastic) Brown Blue Green
Wheel type sensor M14x1.0 thread. Two wires only. - Brown Blue
Brantz dividing prescaler interface for digital electronic speedometer pulse sources Brown Blue Green
Ford/GM/Fiat/ Lada/ Vauxhall/VW gearbox sesnor. M18x1.5 thread, square drive. Will require reshaping. Red White Black or Silver
Japanese gearbox sensor. M22x1.5 thread, lug drive. Two colour schemes are available Red or Brown White or Blue Black or Silver or Green/yellow
This chart lists connections which are equivalent to the grey cable on other Brantz tripmeters Brown Blue Green
Wheel Sensor Installation
Before fitting the sensor to the vehicle, connect it up to the tripmeter and test its' functionality by touching the sensing end many times with a screwdriver, and note that the tripmeter increments. A bracket to mount the sensor to the suspension strut should be made rigid enough to prevent flexing. Bolt heads (a minimum of four for accuracy) should pass squarely across the face of the sensor all at a distance of 1mm (IMPORTANT). Socket head bolts cannot be used as they cause problems. Correct fitting of the sensor can be checked by monitoring the voltage across the sensor with a voltmeter. When connected to the tripmeter and the sensor is next to a bolthead the voltage should be about 2 to 2.3volts. When the sensor is clear of the bolt head the voltage should be about 4.0 volts or slightly more. Check that all (four?) bolts give similar results. If the tripmeter is put onto calibration figure 0001 then all four bolts should cause the tripmeter to increment.
Wheel Sensor Installation
Wheel Sensor Installation
Gearbox (Japanese/Ford)  
Most Japanese manufacturers have standardised their gearbox outputs to accept a M22 x 1.5 threaded sensor which has a round peg drive with a 'lug' pinched onto the side. Unscrew the original speedometer cable from the gearbox, screw in the Brantz Jap sensor with the drive pin in place, and screw the original speedometer cable into the sensor. Wiring is to the Brantz GREY cable as follows: Green to Green, Blue to Blue, Brown to Brown. Some Jap sensors have a different colour code and are wired as follows: Green to Black or Silver, Brown to Red, Blue to White. Many Ford/GMfVauxhall FiatIVW/Skoda/Lada gearbox outputs are similar in that they have a square drive and a Ml8 x 1.5 screw thread. The Brantz Ford/GM sensor will fit many of these vehicles but will require some degree of filing/cutting/drilling before they are an acceptable engineering fit. Select this sensor only if you have the skills to do this. Wiring is the same as for the Jap sensor above.
Japanese Gearbox Ford/GM Gearbox Sensor
Japanese Gearbox Sensor Ford GM Gearbox Sensor
Universal Speedometer Cable  
This plastic unit fits in the length of almost any speedometer cable, though some old cables require holes to be slightly enlarged due to 'chunky' cable dimensions, and some modern speedometer cables need ingenuity to dismantle them as manufacturers seem to want to prevent customers from separating the inner from the outer. Generally with the so-called 'sealed' cables, a section of sheath from the centre of the cable should be removed first to obviate the fixing system used on the ends of the inner. Replacement lengths of sheath can always be put back in after the cable has been separated. Heat-shrink sleeve, particularly the type which is adhesive-lined makes easy repairs to segmented sheaths. To assist with fitting, a cross-section of the universal sensor is shown. Note that the rotor floats in air and puts no additional strain on the speedometer drive, but this construction demands that the sensor should not be subjected to 'end thrust' which could be produced by a worn cable, or being fitted on a bend in the cable. Modern sensors can be stripped to help with fitting in difficult cases. Connections are Brown to Brown, Blue to Blue; Green to Green.
Universal speedometer cable installation
Universal Speed Cable Sensor
Speedometer cable installation

1. Choose a straight location for the sensor where it will not be damaged by heat or vibration. Note the length of inner cable which protrudes from the outer sheath so that this can be replicated when the sensor and cable assembly is completed.
2. Pull out the inner core.
3. Remove 13mm of sheath at the proposed location of the sensor by using a fine-tooth metalsaw. 3/ Remove any burrs with a fine file.
4. Place a petrol hose type screw clamp on each end of the sensor.
5. Insert a loose end of the speedometer cable inner and push very firmly through the internal friction bushing of the sensor. Take care not to kink the speedometer cable inner.
6. Feed the loose end of the inner through the last piece of sheath until it fully inside the sensor. Lightly tighten the clamps. The clamps could be substituted by adhesive lined heat-shrink sleeving. This product is useful for reconstructing cable sheaths which have been cut into several sections. Make sure the cable dimensions are the same as when you started.
7. Correct functionality of the sensor can be tested with a voltmeter connected between vehicle negative ground and the blue terminal of the sensor. When the tripmeter is connected the terminal will change between 0v and +5volts as the sensor is slowly rotated. There are 5 pulses per sensor revolution.

Trouble Shooting  
The Laser 3 requires first class tight and preferably soldered electrical connections (definitely not crimps!) to a power source derived directly from the vehicle's battery terminals. See the Guarantee sheet for definition of the required normal interference-free vehicle. A document exists on the website off the opening MENU page covering advanced troubleshooting tips.
Remote Controls


Pro Remote  

The Pro Remote for the Brantz Laser 3 (Radio model) has a screen and a port connection for a portable computer to permit the storage of road information for later analysis (suitable software required). The device can be powered either from the car, or from the internal battery (PP3).
When the unit is used as a remote control, the buttons on the front of the case can be used as follows:
Zero Lower: Duplicates the function of the 'Zero Lower' button on the main tripmeter. Depending on which mode is being displayed on the lower readout of the main tripmeter, this button will zero the displayed distance, acceleration time, or zero/restart the stopwatch in the same way that the main tripmeter button does.
Zero Upper: Duplicates the function of the 'Zero Upper' button on the main tripmeter. Note that just like the main tripmeter button, the remote Zero Upper button requires a three second press to zero the upper if the upper readout is in distance reading mode. If the main tripmeter is in Stopwatch mode, the remote will stop and/or zero or re-commence the stopwatch. If the main tripmeter is in average speed mode, then the remote will zero the average speed.

Split Button: Controls the upper distance readout to facilitate the setting of distances at a given point should the readout disagree with an 'official' figure given for that location. Press the Split button as the location is passed, and enter the correct distance figure (starting at the most significant figure). When the distance has been entered press the Unsplit button. Note that the distance figures are six digits long, but if say only three digits are entered before the readout is Unsplit, the remaining three figures are entered as zeros. Note also that if the vehicle has moved since the Split button was pressed, then the distance moved up to the location where the Unsplit button was pressed will be added to the distance entered so that the official distance remains accurate. This is the only way to pre-enter distances accurately whilst on the move.
The Pro remote will double as a Driver's monitor. Should the driver wish to have a readout of the tripmeter distance figures or the digital fuel gauge, or current speed, or time of day then the Pro remote can be set in front of the driving position. As the unit is radio controlled, no wiring is necessary. To help the driver, the readouts can be viewed all at the same time, or the Select button can be pressed and the 'View Max/Min' button can be pressed when the required item has been selected, so that just the items of interest (say speed or fuel) can be shown on the readout. The lights can be turned on or off by the Lights button. The Off button must be pressed for three seconds to switch the unit off. The Pro remote / Driver's repeater buttons can be used at the same time as the standard remote control (radio version). A computer can be plugged into the '9 way D' connector to record the tripmeter information. This could be useful for recording practice or an event. Data is in ASCII form and a special software package is available to run on the computer under 'Windows'.
Driver's Repeater: The wireless link can be used to present the driver with his own display of data such as speed, time, fuel, distance etc on a separate readout unit (The 'Pro Remote').
Data Collection Unit: Data from the tripmeter can be stored every second into a PC when required for stage analysis. The PC is connected via its' serial port to the 'Pro Remote' data port which is radio linked to the Laser 3, and the PC should be running the appropriate Brantz software.

Standard Radio Remote Zero Units: This unit has 2 control buttons which suffices for most co-driver needs, and operates over a wireless link to the Laser 3 computer. It needs a PP3 battery. If the 'Total' readout is in stopwatch mode the button marked 'Upper' will with a fast press commence the upper stopwatch (say at a stage start). A second fast press will freeze the time of day and upper stopwatch (say a stage finish). If pressed for more than 2 seconds it will restore the current time of day to the 'Time' readout and zero the upper stopwatch. If the 'Total' readout is in 'distance mode' then the button will zero the distance, but only after a three second press. The button marked 'Lower' will control the lower 'Trip' readout.

A hard-wired 'push-to-make' remote button can be connected between the 'RR'(Rem/Rev) terminal connector and negative ground to zero just the lower distance readout. Remember to configure 'RR Setup' on the menu to 'RR=-dist' as otherwise the Laser will think the ground signal is the reversing light and will illuminate the -Dist light on the Laser face when pressed.

The RR terminal on the upper connector in the rear of the computer can be configured by 'Select Edit Item' as a Reverse instruction (RR setup = -dist) and can be connected to reversing lights; -12v signals a reversal (use a relay if the vehicle's logic is the opposite of this) , or the 'RR' Terminal can be configured to accept a hard wired remote zeroing button for the lower readout as described above (-12 volts = zero readout. Configure RR setup in the 'Select Edit Item' menu as REMOTE-tp).


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