New Directions

900 Echols Street SE
Vienna, VA 22180    703-319-0840

High Performance, Affordable Accessories for
Pinewood Derby, Hot Wheels, Soapbox Derby, and other racing formats.

 

INSTRUCTIONS for the BESTTRACK SPACE DERBY ELECTRONIC FINISH LINE

 1. Disregard the BestTrack instructions regarding using a single filament laced back and forth (Steps 7 and 8 of the Space Derby Track Instructions). Instead, make each lane separate, fixed at the start line and a separate weight for each lane at the finish.

The advantages are:

a. Installing the sensors on each filament requires assembling several components in the correct order. It is easier if you deal with each lane separately.

b. It assures that all lanes have the same filament tension. This makes for a more fair race, since the tighter the filament, the better the spacecraft performs.

c. If a filament breaks, it will not bring down the whole track. It is much easier to make your repair.


Low cost weight

Place a nut and washer on an open hook, embed in a coffee can filled with cement.

The hooks are open, so you can use this simple knot.


Weights should be low,
so if a line breaks, it won't
have far to drop.

2. Attach your new finish line bar to the tower with the black box on top, and the green light aiming back at the start line.
Note: The bar will be "upside down" from the BestTrack manual illustrations.

3. For each lane termination, install your eye hooks in the normal manner. First thread on a nut so that there is 1/2" of exposure.

4. Mount a brass rod on the back side of the bar and tighten another nut on the end loop.


The brass rod exits upward at right angles to the bar and points toward the start line. Tighten securely.

5. Mount the plastic sensor on the brass rod. Trap it between two of the black rubber hose segments. Make sure the white wire exits toward the finish line bar.

If you ever lose the hose segments, they are standard 3/32" vacuum hose, available at your auto parts store, cut to 1/2" length.


6. Wind the white wire several times around the brass rod to keep it neat. Plug the end of the wire onto the mating contact of the green circuit board.

Thread the filament through the carrier, then through the brass sensor grommets, then through the spring, and finally through the eyehook and down to the weight.

Hint: You don't have to thread the filament all the way through the spring. Just go around and around and it will finally be there. (This is not always obvious)

The original plastic tubes supplied by BestTrack are not used.

7. Adjust the position of all elements so that:

a. the brass rod is parallel to the filament. You can adjust by gently applying bending force to the rod.

b. the spring gently touches both the eye hook and the rear sensor grommet. (By the way, the spring is an important feature of this design, as it significantly reduces the impact forces, and possibility of damage, by increasing the length of deceleration.)

c. ideally, the filament passes through the grommets without touching. Actually, it is ok for them to touch, but lightly.

8. Install the battery to test. After the initial light show, flick each of the grommets together with your fingernail. This will cause the
lights to display finishing order. The more light, the faster the spacecraft. The lights will display finishing order for 20 seconds,
and then reset automatically.

Note: This test cannot be performed unless the spring is in place.
The spring conducts electricity to the finish line.
  

 

 

 

If all is well, and your finish line has been equipped with Computer Option, proceed with the following instructions.

9. Identify the magnetic switch consisting of two parts: The magnet (a silver rare earth rod magnet) and the switch assembly. These components mount to the starting gate tower, on the right rear leg indicated by the red circle.

When the magnet is close to the switch, the switch passes current. When the magnet is withdrawn, the switch opens, starting the timer.

10. Mark the bottom of the start gate assembly (part #6 in the BestTrack Instructions) where it passes by the tower leg.
Make two marks, one on each side of the tower leg. You will attach the magnet to part #6 between your marks.

11. Mount the magnet to the start gate assembly between your two marks using clear adhesive tape. You can mount it in the inside corner of the angle, or along the edge as shown. If you choose to mount it on the edge, you will need to temporarily remove the gate assembly from the stand.

12. Attach the switch assembly to the inside of the tower leg so that the silver connector points down to the floor, and the mid point of the black box is close to the magnet. Use the spring clip to hold the magnet switch on the leg exactly as shown.

13. Install the cable assembly, connecting the magnetic switch, the finish line, and your computer. If it is feasible, consider suspending the cable from the ceiling in order to avoid walking on it when retrieving the space rockets. Running the cable through a dropped ceiling is often possible, and is a great solution. Tripping on the cable is often fatal for the connectors. Therefore consider using strain reliefs such as nylon tie-wraps to prevent connector damage. Suspending the cable between the start and finish towers is NOT recommended.

14. Test the magnetic switch. When you power up the finish line by inserting three AAA batteries, there will be a rippling red light show, and then the green light should wink once every second. When you lift the rear of the start gate, the green should light steady for one full second, and then go dark. If you get this behavior, the magnetic switch is functioning properly.

15. If your computer has a serial port (9 pin male), plug the cable assembly in directly. If you have only USB connectors, you will need to get a USB-Serial converter device, and install its software driver on your computer.

16. The Judge transmits the data at 9600 baud, 8 data bits, 1 stop bit, and no parity. You may run races under DerbyMaster or GrandPrix RaceManager software. You may also interact with the Judge under a number of communication programs such as HyperTerminal, which is part of your Windows operating system from Win95 through WinXP. Starting with Win7, it is no longer included. However you can download it for free at a number of web sites. Google "Hyperterminal free download".

17. When your derby is over, disassemble the sensor components. Do not attempt to store the finish line bar with the brass rods and sensors in place. Keep the finish line bar separate from other components to protect it from damage. A custom-made box where everything has a place would be an wise investment for the years ahead.