Dashr timing gates a designed to work indoor and outdoor. When operating outdoors on a hot sunny day, we have a few suggestions to ensure your testing goes smoothly.
1. Orient the laser towards the sun, so that you hit the shaded side of the athlete. Most fields are oriented north/south, so in the mornings you want to have the lasers pointing east and in the afternoons point them west.
2. Have the reflector set-up lower than the laser so that the laser angles down towards the ground. Orient the reflector so that it is angled back up at the laser so that it is relatively perpendicular to the beam. This is important because light/reflections behind the reflector are sensed by the laser, by angling it down - the backdrop is the ground, which stays pretty constant.

3. Make sure you have fresh batteries, we suggest AA lithium ion batteries for outdoor use.
4. For extended use outdoors in the sun and heat, make sure you use Heat Shields to prevent the lasers from overheating. Overheating can dim the beam and reduce range.
5. Avoid white/bright clothing as they can be reflective. Some groups keep a dark colored penny with their system incase the conditions are extreme and an athlete has a reflective shirt.