Hi, I would like to trigger 6 flashes in parallel for a highspeed photo setup. The art is to get them perfectly in sync. The flash duration is just approximately
1/25.000 of a second (0.04ms). Therefore I would like trigger them via cables and not radio remote triggers.
I'm using a Teensy 3.5. Some questions arise as I'm unsure about some of the specs. As you can see in the schematic drawing, I would like to trigger the 6 flashes via a single pin of the teensy. My idea is to use a dual optocoupler LTV825 and a quad optocoupler LTV847. Both have an identical I_f = 50 mA and U_f = 1.2 V.
In order to enlighten the LEDs in the optocouplers I split them up into three parallel groups (A, B, C) with each two LEDs in series. With a 100 ohm resistor in each group the current should be 9 mA.
I'm a bit unsure about the maximum and recommend current for a pin on the Teensy 3.5. I read on the net that the max is 40mA but recommend 20 mA. Due to the three parallel group the total current is the sum of the groups currents (I_Total = 3* 9 mA = 27 mA).
As far as I know, setting up diodes in parallel might be problematic. As the current takes the way with the lowest resistance. I'm afraid that one or two of the groups might not fire. Due to the fact some of the resistors or LEDs might variate a bit.
Thanks a lot.
1/25.000 of a second (0.04ms). Therefore I would like trigger them via cables and not radio remote triggers.
I'm using a Teensy 3.5. Some questions arise as I'm unsure about some of the specs. As you can see in the schematic drawing, I would like to trigger the 6 flashes via a single pin of the teensy. My idea is to use a dual optocoupler LTV825 and a quad optocoupler LTV847. Both have an identical I_f = 50 mA and U_f = 1.2 V.
In order to enlighten the LEDs in the optocouplers I split them up into three parallel groups (A, B, C) with each two LEDs in series. With a 100 ohm resistor in each group the current should be 9 mA.
Question A) Are these 9 mA enough for the LEDs in the optocouplers (I_f = 50 mA)?
I'm a bit unsure about the maximum and recommend current for a pin on the Teensy 3.5. I read on the net that the max is 40mA but recommend 20 mA. Due to the three parallel group the total current is the sum of the groups currents (I_Total = 3* 9 mA = 27 mA).
Question B) Are these 27 mA ok for a single pin?
As far as I know, setting up diodes in parallel might be problematic. As the current takes the way with the lowest resistance. I'm afraid that one or two of the groups might not fire. Due to the fact some of the resistors or LEDs might variate a bit.
Question C) Is there a command to fire 3 pins in parallel or would it be enough to do three digitalwrites in sequence? (What time is consumed by an digitalwrite command?)
Thanks a lot.