Hello to everyone, this is my first post here.
I am trying to build a device to measure the speed of objects falling trough a pipe, which can be pressurized or depressurized at will, for physiscs demonstrations.
My plan is to use 2 infrared (could be visible light if that is easier) emitter/detector pairs, connected to a chronometer. When the first beam is blocked by the falling object, the chronometer starts, when the second beam is blocked, the chronometer stops, and I can get a reading.
I figure I can divide the project in the following parts: 2 photo triggers, a clock signal generator with a known frequency and start and stop 'switches', a counter for the clock's 'ticks' and a display.
So far I have found tutorials on the phototriggers using an emitter, a phototransistor, a general purpose transisitor and some resistances, and tutorials on making 'clocks' based on a 555 (but not one with simple start and stop switches). I also found a way to count the clock's 'ticks', but I am not sure on how to divide it by a reasonable number so that I can get my final display in the 100's using three 7 segment LED displays.
My question for you, is how to bring this all together. I am asking for pointers to material that can help me figure it out myself, but if you could take the tame to draw a full schematic, or schematics for the different elements, I will be in your debt.
Thank you for your attention.
I am trying to build a device to measure the speed of objects falling trough a pipe, which can be pressurized or depressurized at will, for physiscs demonstrations.
My plan is to use 2 infrared (could be visible light if that is easier) emitter/detector pairs, connected to a chronometer. When the first beam is blocked by the falling object, the chronometer starts, when the second beam is blocked, the chronometer stops, and I can get a reading.
I figure I can divide the project in the following parts: 2 photo triggers, a clock signal generator with a known frequency and start and stop 'switches', a counter for the clock's 'ticks' and a display.
So far I have found tutorials on the phototriggers using an emitter, a phototransistor, a general purpose transisitor and some resistances, and tutorials on making 'clocks' based on a 555 (but not one with simple start and stop switches). I also found a way to count the clock's 'ticks', but I am not sure on how to divide it by a reasonable number so that I can get my final display in the 100's using three 7 segment LED displays.
My question for you, is how to bring this all together. I am asking for pointers to material that can help me figure it out myself, but if you could take the tame to draw a full schematic, or schematics for the different elements, I will be in your debt.
Thank you for your attention.