Espritmodel.com Telemetry Radio
Reply
Thread Tools
This thread is privately moderated by cyberhoops, who may elect to delete unwanted replies.
Old Oct 16, 2012, 06:41 PM
Registered User
cyberhoops's Avatar
Seattle
Joined Feb 2006
930 Posts
Discussion
Nerf Chronograph

I was playing around with a couple Nerf guns, and reading some of the posts about people modifying Nerf guns for better performance. One thing led to another and I could not resist the idea of making a chronograph, or velocity sensor, for Nerf darts.

I had all of the hardware I needed already lying around - mainly an Arduino controller, and an LCD display. Add to that a pair of infrared LED light sources and detectors from Radio Shack and I was good to go.

The idea was to place the two sensors in a PVC tube spaced 4 inches apart. Then time how long it takes for a dart to trip the two sensors and compute speed. Since the Arduino can do timing in microseconds it is more than capable of doing accurate speed for a dart moving around 100fps.

The Arduino 5v output is connected to the transmitter led through a 270 ohm resistor and to ground. Two analog input pins are connected to the receivers and then a 270 ohm resistor to ground. Very simple circuitry. The LED's are mounted 4 inches apart in a 1 3/8 inch PVC tube. About the only thing I did wrong was not mounting the LED's to be flush with the inside of the tube. My mounting has them sticking into the tube about 1/8", which means the dart can hit them. That means I have to be slightly more careful in settup up the shot to go down the middle of the tube.

Once the speed is calculated, the display is a Sparkfun LCD-09395 serial LCD with 2 lines of 16 characters. That just takes 5v power, ground and a single digital output pin from the Arduino which makes it very simple to use. After the picture was taken I also added a second line to the display for the average velocity of the previous 5 shots.

It did not take long to get it all working - 30 minutes to get the first breadboard version working and a couple days to put it all together.

It anyone is interested in the code (Arduino sketch), or the circut diagram, let me know and I can make that available.
cyberhoops is offline Find More Posts by cyberhoops
Last edited by cyberhoops; Oct 17, 2012 at 11:17 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 28, 2012, 05:06 PM
Registered User
Joined Oct 2012
1 Posts
Source code

Hi.

I'm very interested on making a Arduino based chronograph.

So, could you give me the source code for this?

Send it to: mil_ndollars2008@hotmail.com

I'll be very grateful if you help me.
Pablar is offline Find More Posts by Pablar
Reply With Quote
Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Nerf guns platnuim1 Non R/C Items (FS/W) 2 Jul 02, 2012 07:10 AM
Discussion Nerf Stampede Motor Replacement (Non-RC, help a noob!) stoph RC Toys 8 Mar 13, 2012 09:58 PM
For Sale Seiko Men's Alarm Chronograph Watch #SNA061 Final Price Drop $100 shipped!!! russainred95 Non R/C Items (FS/W) 3 Sep 02, 2009 02:07 PM
For Sale Swiss Legend Commander Chronograph Watch jafo216 Non R/C Items (FS/W) 2 Jul 07, 2009 04:49 PM