Alpha Charlie
This simple chronograph measures the speed of a projectile by measuring the time it takes the projectile to travel a known distance. This is accomplished with 2 IR emitter/detector pairs. Each pair is configured into a beam-break sensor with the output going to ground when triggered. Each of these circuit outputs is attached to a digital IO pin on the Arduino or ESP8266.
Current software uses the CCOUNT register of the ESP8266 which increments at the full clock speed of 80 MHz. This translates to an impressive precision of 0.0125 fps at 1000 fps! This is much improved over the original Arduino version which used the micros() function and was only precise to 4 microseconds for Arduino. However, it's unlikely that the chrono is accurate to this level of precision. Other errors and 'slop' in the design multiply to limit the accuracy of the measured speed to within a foot per second (or so) of the actual speed. Still pretty impressive for less than $40 worth of hardware. Next update should begin to incorporate a web interface (via the ESP8266 built-in WiFi) and possibly also a camera trigger out for high speed photography.
nobcha
Antonio Cesar de Oliveira
vybhav-nag
Dilshan Jayakody
To the "makers" leaving previous comments.
Have you learned to read English yet. The GitHub repository with the FULLY COMMENTED CODE, indicating the precise answer to this "question" was posted in May of 2016, a full TWENTY TWO MONTHS before your collective failures to "do the homework." ( SMH ! )
Not an edit or update at some later time of the code, the full sh'bang! The server indicated that the answer was PUBLICLY AVAILABLE almost two years BEFORE your telling incuriousity. Which begs the questions, "What else do you insist on having spoon fed to you? Just how intellectually sloven are you?"
Your demonstrated willingness to be this lazy on a topic adjacent to firearms indicates your unfitness to be with firearms. This is a big, AND AVOIDABLE part of why "anti gun nuts" have valid reasons for their position!
DO BETTER or step away from the weapons !!!!!
P.S.
YES, even this long after the original "questions" this reply is not only valid but REQUIRED. This kind of demonstrable idiocy MUST never be left to stand uncorrected. This project is for a ballistic chronograph. Such a device is used to qualify ballistic parameters of projectiles, FROM GUNS. Be they NERF, Airsoft, or Glock, they ALL demand the same INFORMED RESPECT. There was no informed respect evident in the clearly sloven questions previously asked.
A question, respectful of ones own possible/ PROBABLE ignorance would have been worded thusly,
" I'm having a problem understanding the assignment of pins on the processor to each of the gate triggers. Either I'm not seeing it in the code or it was left out. Please advise."
To which a calm answer would be:
" Read lines 10 and 11 of the code at https://github.com/alphacharlie/ESPx-Chronograph/blob/master/ESPx_Chronograph/ESPx_Chronograph.ino "
Upon which you should have learned 3 things.
1. The location of your answer is contained in source code.
2. The exact lines in the code your exact answer is written out upon.
3. That there is an inherently and intuitively obvious location and manner to acquire answers of this sort WITHOUT BEING SO BLOODY LAZY!
fin