Picture of Paintball/Ballistic Chronograph
Create a low-cost Paintball Chronograph for less than $40!

A ballistic chronograph is a device that records the velocity of a projectile. This particular chronograph I have made has only been tested with a paintball gun and it is relatively simple to make. I have also implemented a function that can record the rate of fire at which a device is firing.

Seeing as you will be using a device that shoots projectiles at high speeds to test this chronograph, use your head and be smart. Follow all safety procedures and guidelines that pertain to the use of the paintball marker or other device that you are using to shoot projectiles.

Step 1: Electronic Requirements

Although this chronograph is pretty easy to build, a basic understanding of electronics and soldering skills is essential. The most trouble I had with this project was making the PCB. I use the toner transfer method, but that doesn't produce very nice boards when your laser-jet printer needs a new cartridge. The board itself has some spots that are pitted and doesn't look too neat, but it gets the job done. If you aren't able to make your own PCB's, one can just use some perfboard and point to point wire everything together.

Here is a list of the following electronic components required:

- 2x 47µf Electrolytic Capacitors
- 2x 0.1µf 0805 SMD Capacitors
- 1x 0.01µf 0805 SMD Capacitor
- 1x 0.01µf Ceramic Capacitor
- 2x 27pf 0805 SMD Capacitors
- 2x 10kΩ 0805 SMD Resistors
- 2x 2.4kΩ 0805 SMD Resistors
- 2x 470Ω 0805 SMD Resistors
- 1x 150Ω 0805 SMD Resistor
- 2x 100Ω 0805 SMD Resistors
- 1x 4.7kΩ Trim Potentiometer
- 1x 1N4148 Diode
- 1x LM7805 5v Regulator
- 2x TSOP4838 IR Detectors
- 2x IR Transmitters
- 2x Female 2-pin Molex Connectors
- 2x Male 2-pin Molex Connectors
- 1x 5-pin Header
- 1x MMMBT2222A General Purpose Transistor
- 1x 12MHz Crystal
- 1x Tactile Switch
- 1x Rocker Switch
- 1x PIC18F13K50 SOIC Microcontroller
- 1x 16x2 LCD Display
- 1x 9v Battery Clip

Most of these components I had already had on hand, but I would estimate the cost of this project to be around $30-$40. I have not shown any of the SMD components (except for the PIC) in the photo below.

I have gone and posted print screens of some places where you can buy the components. Some components couldn't be bought as 1 or were cheaper in higher quantities, that's why you may see some extra parts in the pictures. Many of the parts can be bought at a good price at www.dipmicro.com. I will tag the cost of each product in the photos below. With all of these parts, not including the board, it came to $38.11 to purchase all the components for this chronograph with all shipping included except for the PIC18F13K50 bought at Digikey. Then it would be a couple more bucks for the PVC pipe. Also, if you want to save $3.39, you can buy 16x2 LCD Displays on eBay for $2.99 including shipping.
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bpauza1 year ago
@Regax, how much would you sell a working one for?
siffup2 years ago
Check the code, even if it compiles, it can never work!
Either fix it or delete this mess.
Regax (author)  siffup2 years ago
You sent me an email in which you stated the chronograph always says you are shooting at 16960 fps. This happens when neither of the IR receivers are seeing the IR transmitted signal. Double check that your IR transmitters are PWMing at 38KHz. If the outputs on the 38KHz IR receivers don't change when you obstruct the view of the IR transmitter, that is your problem. Apologies for not getting back to this post sooner.
sadstorm4 years ago
Gran trabajo, pienso intentar poder contruir uno, peor me gustaria saber si a parte de darme los fps, podria darme los m/s y julios.

¿Como podria programarlo? Gracias por todo un saludo.
Has conseguido respuestas con el tema del cronografo?
manza_19832 years ago
Hola Sadstorm, estoy interesado en contruir un cronografo como el del amigo Regax, tu lo has conseguido?
neodymium3 years ago
what is the maximum fps you think it can detect? I want to build this for my airspft gun but it shoots over 500fps (not sure exatly how much) but I need to know it it will even work. thanks.
bschiera3 years ago
Very good project, i'd like it, please, can you tell me the correction for reading the velocity in m/s, thanks.
Considering the size of the paintball relative the ID of the pipe are you worried about back pressure slowing down your paintball? I would assume it would have some effect on your measurements because aerodynamics are different.
kswift23 years ago
Is There a reason the .pdf files are blank, can new files be uploaded of saved to another site.

I will be building this and the layout files would help a lot.

Regax (author)  kswift23 years ago
I'm not sure if users without a "Pro" membership can view PDF files (This was brought to my attention a couple of months after I had already created this instructable). I'll create a zip file with all of the contents required for the project and post it in the last step.
Thanks for this. I just finished building and testing. Didn't like the SMD componnents so I built it off you schematic with the old fashoned parts :D Works great...now I was thinking of redesiging the sensor to have a wider field for use with a firearm. works great with my paintball guns.
Regax (author)  ravenbrother4 years ago
That's awesome! Glad this instructable helped you build your project! I'm not sure how a person could make a wider field for use with a firearm. You could make a line of IR transmitters and receivers, but you would have to make sure that the transmitters have very narrow viewing angles so the stray light does not cross into the path or another IR detector. Let me know if you find out a way to do this. Good luck!

I was actually looking at motion detectors something like this from radio shack..

PIR Sensor Module then limiting it's field of vision to a slit.
Ferouque4 years ago
Regax well done mate but it all went right over my head !!!
it totally ment nothing to me

how about i buy that one of you ?? ;-)
tromano24 years ago
Interested in possibly using this to chrono airguns (.177/.22 cal.) as well as .68 cal. paintballs. Any idea as to the maximum FPS this chrono can detect?
ddávila4 years ago
Hi I would like to know wich other PIC can I use to build this amazing chrono?!!! is just that i cant find the 18F13K50 at my city.
Regax (author)  ddávila4 years ago
Well you would want a minimum of 11 I/O pins, a hardware PWM module, at least one 16-Bit Timer, the higher its operating frequency the greater its accuracy, so I would recommend a PIC18F that operates at a speed of at least 10MIPS (40MHz) to get pretty good accuracy. Also, I use one external interrupt for the RoF mode, so that would be an asset.

Here is a nice program from Microchip that will narrow the results down to based on what you need in a PIC.

A pretty common chip that you could use would be a PIC18F2455, however you will have to modify the driver files for that device or else replace my driver files with microchips driver files.


ddávila Regax4 years ago
:( I think I will keep searching for de 18f13k50 because I'm not too much experimented on this things so .... I could get lost in this.
Regax (author)  ddávila4 years ago
Well if you purchase online at all, you can check out Digikey or buy them straight from Microchip at http://www.microchipdirect.com/ProductSearch.aspx?keywords=PIC18F13K50. When you do purchase them, make sure you purchase them in a "SOIC 300mil" package type if you plan to use my PCB. If you are just breadboarding buy a "PDIP" package.
Regax (author)  Regax4 years ago
The link didn't show up, sorry, the PIC Chip Selector is located at: http://www.microchip.com/productselector/MCUProductSelector.html
robomaniac4 years ago
Your instructables is very good for your first one! Great graphic and explanation.

If you have better lighting when you take those electronic and tools pictures, it would look even more pro! CFL lighting works great. (coolwhite or daylight) You can also play with the setting of the camera before taking a picture.

Keep it up!
Regax (author)  robomaniac4 years ago
Thanks for the tips! I'll be sure to take that into consideration for my next instructable.
rhanson2944 years ago
Excellent instructable! Very well thought out! Would the diameter of the tube make a difference in the reading? I would love to have a shot counter for when I play airsoft.
Regax (author)  rhanson2944 years ago
Thanks! And nope, the diameter of the tube does not matter. You could use a smaller tube and as long as the airsoft bullet manages to break both IR beams it will work the same as this one does.
I'm not accusing anyone but im pretty sure this was stolen from somebody's post for a measuring the velocity of a coilguns projectile. I'll update when i find the website.
Jenna N4 years ago
This is soooo cool!! You should sell them, make some $$, haha!
This is really cool! about how much does it cost to make one?
I just bought all the components from Digikey for $60. Add another couple for the board and I had to buy some etching liquid but you can do it all for around $70 in real life. Figured I'd throw that out there
Regax (author)  rspoelstra4 years ago
Ya making the PCB will up the cost if your don't already have the materials to make one, I had everything on hand so I just estimated the cost. The majority of my stuff is bought off of eBay, which in some cases is much cheaper than Digikey's parts. Just look around for parts, eBay is great for hobbyists that don't need high quantities of supplies.
Regax (author)  Regax4 years ago
I just went and found the cost of all the components at 3 different websites, DIPMICRO.com, eBay.com and Digikey (only for the Microcontroller) and it came to a full cost of $38.11 for all of the electronic components. I have posted all of this information in step #2.
Kinda figured it's possible to find everything for cheaper, I'm just a fan of one-stop shopping. Thought I'd just give an estimate for anyone looking to buy everything.
Regax (author)  rspoelstra4 years ago
The only shipping that I didn't add up was the PIC18F13K50 from Digikey. Of course, shipping could cost you more or less, it is totally location dependent. But you are right, it is much less hassle to order everything from one place and get all the parts delivered at the same time. I find eBay has much slower shipping than most other sites such as Digikey. Good luck on your project! Feel free to post pictures when you've got it all finished.
Plus when you add shipping, it starts to add up.
Create a low-cost Paintball Chronograph for less than $40!
profpat4 years ago
very good, will try to modify for airsoft or airgun use! thanks
Regax (author)  profpat4 years ago
If you're modifying it for air gun use, seeing as the pellets are so small you may have to decrease the intensity of the IR beams or make a barrel where the beams are more "concentrated".

To decrease the intensity of the IR beams you can add larger resistance values for R4 and R5. Or else you may be able to decrease the PWM frequency from 38KHz to something a bit smaller, which will decrease the sensitivity of the IR Detectors. If you go too low though, they won't detect a beam at all.

profpat Regax4 years ago
great! will do as you suggest, also i am planning to use a smaller pvc pipe or tube, i was planning to use a umbrella stem or old tv antenna elements..
Regax (author)  profpat4 years ago
Good idea! Feel free to post pictures of your prototype when you get it made!
shahzade4 years ago
Hey great Instructable!
I like how easy and straight forward it is!
But I have a question, you write "The PIC is setup to run at 48MHz. It takes 4 cycles to perform one instruction..." I think one instruction is like one loop? One time going through the whole script? How did you find out how many cycles it takes to run the script. Is that a given characteristic of the PIC or is it depending on the length of your script and how complex it is?
Well thanks a lot.
keep it up
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