Start Light Tree

A start light "Christmas" tree is a great way to visually signal the start of each heat. If you manually trigger your start line, the light tree can be the cue for the starting line operator to release the start gate. It is even better when you pair a light tree with a solenoid start gate, so the cars are released when the lights hit green.

Commercially Available Light Trees

  • New Directions - Offers a light tree unit that can be linked to one of the solenoid operated start gates that they offer.
  • Micro Wizard - Offers a combined solenoid start gate and light tree unit that will work with their timers.

Do-It-Yourself Light Tree

These PWD Starting Line Controller Plans were submitted by Randy Underwood and use ultra bright LEDs for the lights. You need to provide a 12V power supply for the lights and optional solenoid gate and a 9V power supply for the control circuit (see construction notes). Once we get some photos of a completed system, we will post them.

If you have any questions relating to the electronics, please contact the author of the plans, This email address is being protected from spambots. You need JavaScript enabled to view it.. Any questions relating to the GrandPrix Race Manager software can be directed to This email address is being protected from spambots. You need JavaScript enabled to view it..

 

Version 7.0 and above of GrandPrix Race Manager software can provide a kick-off signal to the light tree. The light tree will then take it from there, controlling the count down of the lights and activating a solenoid start gate (optional) when the lights hit green.

Start Light Sequence
The following is the light sequence used by this circuit, which models that used in drag racing. However, the bottom red lights do not indicate a false start, just the end of the light sequence. In the GrandPrix Race Manager Hardware Options screen, you can setup the software to trigger the tree off of Pin 4 or Pin 7 on the serial port.

  1. The Prestage lights come on when power is applied to the light tree
  2. The computer operator kicks-off the light sequence by clicking on the Ready Timer button in the software
  3. The Prestage lights turn off
  4. Yellow light sets 1 thru 3 turn on and then off in sequence
  5. Green light set turns on and solenoid is activated (if used) signaling the start of the race
  6. Solenoid is turned off (if used)
  7. Green light set turns off
  8. Red light set turns on and then off
  9. The Prestage lights turn back on for the start of the next heat

Start Light Tree Plans
These 12V DC light tree system plans were submitted by Randy Underwood, and use ultra bright LEDs for the lights. You need to provide a 12V power supply for the lights and optional solenoid gate and a 9V power supply for the control circuit (see construction notes). Once we get some photos of a completed system, we will post them.


Notes on Construction:

  • This circuit was designed to use a 9V and a 12V power supply. The 12V power supply drives the lights and the solenoid gate, with the 9V supply powering the control circuit. If not using a solenoid gate, you can modify the circuit to power the lights using a 9V power supply, but the lights will be a bit dimmer.
  • Make sure that the power supply driving the lights (and solenoid, if applicable) can handle the load of everything being on at the same time.
  • The solenoid control portion of the circuit is optional and anyways would only apply if you had a solenoid that could trigger off of 12V. If you do not need the solenoid control, then you can remove C1, D1, D2, R1, Q1, SW1, and S1 from the circuit.
  • Keep the cables away from extension cords and power supplies as these may lead to electronic interference.
  • There are a variety of bayonet light sockets that you can use. These plans list one, but you can also find others online, depending on how you want to mount them to your tree.