Hi everyone, today we will revisit a projet i have done in 2010. An Air Rifle Chronograph. This device will telling you the speed of a projectile. Pellet, BB or even air soft BB plastic ball.

In 2010 i bought an air rifle for fun. Was hitting cans, bottles, aim. I know that the speed of this gun was maximum 500 feet/s. Because it's the canada's law. Some stronger air rifle are available but you need to have a licence for and you can't buy those thing at Walmart.

Now i had this licence, i could buy another one. But short story, the same gun was available to the U.S. at 1000 feet/s. WHAT!? The same gun ? yes... In canada, the stroke have a hole in it and the spring is softer.

First thing to do is fill up the hole. That's what i done with solder. Next thing to do was to order a replacement spring. But wait... what is the current speed of my new toy ? Is the spring really necessary ? I dont know and i want to know. I want to know now but how ?

That's why i did this project. All i needed was 2 sensors, a uC and a display and we are in business.

Last week, i saw my old blue chronograph on a shelf and i talk to myself:"Why dont share this and do an instructable with it ?" And by the way, we could rise the accuracy and add a battery indicator. Put 1 button instead of 2 for on/off. All surface mount. We are now in 2020!

So there it is... let's begin!