My application is a dog race timer using two posts with 3 IR emitters on one pole and 3 receivers on the other pole to accommodate the size of the dog and the obstacle that starts and completes the course. All three of the emitters are fed from the 3.3 V output of the photon. Also, the emitters have a modulated signal created by using a PWM pin feeding a MOSFET. The receiver pole has three IR receivers which are fed by the 3.3 V output of the photon. I hope there is enough power output from the 3.3 V to power all three emitters and receivers.
AND… I’m hoping that power draw will keep the battery from shutting down from low power draw… OOPS I just realized that the way the receivers work is that they are fed 3.3 V on one pin and when the emitter beam is not aligned, another pin stays high. When the beam is aligned, that pin drops to zero. Therefore, on a perfectly aligned timer, there is only the power draw of the photon itself. That photon sends a UDP message as a keep alive every 1 second. In past experimentation, one of the external batteries I used shut down when that’s all the photon was doing.