Moderator with built in Chrono

[Coxworkshop]

What started out as curiosity about the feasibility of adding a chronograph to a moderator has turned into a bit of a passion project for me. The concept is pretty straightforward: make an airgun moderator that has a chronograph and display built in. As it turns out, the implementation is harder than I thought. But it has been a fun chance to learn more about microcontrollers, photosensors, principles of sound reduction, engineering and design, etc., etc. There is way more to all this stuff than you would think.

For example just trying to accurately measure the dB level of a shot is quite complicated. You can quickly go down a rabbit hole. Most decibel meters have a FAST (.125 seconds) and SLOW (1 second) selection. The peak amplitude of an airgun shot is only a few milliseconds in duration. Depending on how the meter samples during its "selection period" (either fast or slow), you might entirely miss the peak. There are meters with an IMPULSE selection meant for capturing those types of sounds, but they are thousands of dollars. Either way a process that seemed like it should be simple and straightforward ends up being significantly more complicated the further you get into it.

It's given me a renewed appreciation for the folks in this industry that have come up with really elegant and high-performing products. They have put more research and work in behind the scenes than we probably suspect.

Anyway thought I would document this ongoing project here. Not sure if it's of general interest, but for any that might be interested in following along I'll try to keep updating as I make progress. Quick video below of the current state of the project:

 

[zx10wall]

Really cool. Keep developing that and I’d buy one depending on unit pricing.

 

[Stubbers]

I've been waiting for someone to do this, really good work! Keep it up!

I think having the screen swing out from the side and face shooter would be cool, hinged so it can rest flat.

-Matt

 

[Miami Airgunner]

Speaking as a guy who designs and manufactures highly vertical items like this on the regular, I'd say you have a damn fine product here. I'd even argue it may be worth patenting.

 

[Coxworkshop]

I've been waiting for someone to do this, really good work! Keep it up!

I think having the screen swing out from the side and face shooter would be cool, hinged so it can rest flat.

-Matt

Ya that was my thinking too. I'm tentatively thinking of something like this.

 

[Stubbers]

Ya that was my thinking too. I'm tentatively thinking of something like this.
View attachment 407972
View attachment 407976

Bingo! You're hitting it on the nose. It's wild I had a vision of this exact device a couple years ago, then Daystate integrated the concept in one of their flagship guns and I was like, oh, the big wigs did it, but here you are making a nice modular one, potentially for the masses! Very cool and ingenious making it tangible! Quite exciting to see.

-Matt

 

[Gramps]

That's a pretty slick idea, sure beats shooting through a crony that is between you and the target. Now it just needs bluetooth and an app so record and safe the data. Like the screen fold out idea too. The only drawback I see if that it can't be used on a non moderated gun. Keep working on it you have a great idea and was mentioned you might want to patent it.

 

[BackStop]

Keep it under $100 and have at least a decent moderator and you will have a winner that will make you RICH!

All my best!

Kerry

p.s.

Don't worry about connecting to bluetooth, wifi, etc. That will only increase the price, but not the appeal. And those things can be offered later as "extras" for those who simply HAVE to have it. (smile)

 

[Miami Airgunner]

Ya that was my thinking too. I'm tentatively thinking of something like this.
View attachment 407972
View attachment 407976

Yeah.. That's hot.

 

[rkmcvey]

Moderator AND chronograph........ base model with swing out screen around two bills would be a bargin. Delux w/bluetooth no swing out screen 250-300 still a bargin !! Don't know if it can be done for those prices and be profitable.

 

[MadCowCrazy2]

What I would like to see is a modular version so you can decide how long it should be.
You could make a certain length that can't be changed but threaded so you can add as many segments as you want.
Heck why not screw 3 electronic parts together so you get a triple reading per shot.
This is something I would be interested in but most modular suppressors are very expensive.

 

[oregondude]

What started out as curiosity about the feasibility of adding a chronograph to a moderator has turned into a bit of a passion project for me. The concept is pretty straightforward: make an airgun moderator that has a chronograph and display built in. As it turns out, the implementation is harder than I thought. But it has been a fun chance to learn more about microcontrollers, photosensors, principles of sound reduction, engineering and design, etc., etc. There is way more to all this stuff than you would think.

For example just trying to accurately measure the dB level of a shot is quite complicated. You can quickly go down a rabbit hole. Most decibel meters have a FAST (.125 seconds) and SLOW (1 second) selection. The peak amplitude of an airgun shot is only a few milliseconds in duration. Depending on how the meter samples during its "selection period" (either fast or slow), you might entirely miss the peak. There are meters with an IMPULSE selection meant for capturing those types of sounds, but they are thousands of dollars. Either way a process that seemed like it should be simple and straightforward ends up being significantly more complicated the further you get into it.

It's given me a renewed appreciation for the folks in this industry that have come up with really elegant and high-performing products. They have put more research and work in behind the scenes than we probably suspect.

Anyway thought I would document this ongoing project here. Not sure if it's of general interest, but for any that might be interested in following along I'll try to keep updating as I make progress. Quick video below of the current state of the project:

wow, great concept and product. A patent can be very expensive. Please research "Provisional Patent ". Gives you 1 year of international patent protection allowing you time to find a partner or sell. You can complete the Provisional Patent process by yourself. I think this is a very marketable product. I wish you well. Bill and Addi.

 

[Airgunmann]

Daystate has something like this but it's integrated into the gun if you could do a all in one with a small display which could swapped out to different air rifles and handle 100 to 150 ftlbs for some 30 cals to you could make a killing especially if it's under 350.00 and maybe modular huma is the only modular model that isn't to spendy

 

[Smitty911]

Well if you want to Patent it, let me know. My Patent Attorney used to work in the Patent Office and his wife was a Patent Clerk. Add to that he was one of the least expensive Patent Lawyers I've ever heard of.

I think my Patent was around $5,500 or less.

Smitty

 

[BlackICE]

A patent is only useful if you are willing and able to pay to have it enforced. The cost to write, file and get it issued it is only the beginning of the process of useful patents. My definition of useful patents are those that have a high probability of a positive return on investment, either from protection against competitors, licensing revenue, or increasing the perceived company value from the additional IP.

 

[Coxworkshop]

In regards to bluetooth/phone connectivity. The micro controller I'm using, esp32-s2, doesn't have any real Bluetooth capabilities. That said the esp32-s3 I think has full Bluetooth capabilities and could potentially be substituted. I'd need to look into that a bit more. The only real cost would be the developing of the android and iOS app. I've not done any phone app development in years so I'm not sure how involved that process would be. For the short term I think I'll put that on the back burner to be revisited.

MadCowCrazy2 - The modular design idea is really interesting. potentially you could just swap the end module/baffle so you could use the same "SilentChrono" (that's what I'm calling it for the time being) on guns with different calibers. Not sure if someone has a patent on modular silencers. I suspect they might and I wouldn't want to infringe.

On the topic of patents, I totally see the value of patents and why they are essential. I'm not opposed to patents. But sometimes they seem to stifle progress and innovation when intuitive ideas are patented. Integrating a chrono into a supressor feels like it fits into the "intuitive" idea category. So a patent isn't something I'm wanting to purse. Again I don't have anything against patents or others that use them. Just in this particular situation it's not something I want.

Got some work done on the aluminum prototype

 

[fe7565]

The ESP32-s3 is an energy hog at 23mA. You should use an NRF52 at 2-3mA, if you want bluetooth.

For the LED sensors should use infrared (3-5mA) and also protect the lens from lead dust accumulation. Daystate's older barrel mounted chronos had that problem.

Running the LEDs at a duty-cycle (flashing) saves energy. Just make sure the flash interval is lower than the smallest pellet length at max potential velocity to be measured.

E-Paper displays use near zero power vs OLEDs or LCDs.

 

[Coxworkshop]

The ESP32-s3 is an energy hog at 23mA. You should use an NRF52 at 2-3mA, if you want bluetooth.

For the LED sensors should use infrared (3-5mA) and also protect the lens from lead dust accumulation. Daystate's older barrel mounted chronos had that problem.

Running the LEDs at a duty-cycle (flashing) saves energy. Just make sure the flash interval is lower than the smallest pellet length at max potential velocity to be measured.

E-Paper displays use near zero power vs OLEDs or LCDs.

Interesting, I'll have to look at the NRF52. Do you know what its analog read speeds are? I had to add some circuity and amp to my photodiodes so they output digital because the analog read on the esp32 is so slow. I'm getting digital reads on the order of 1 microsecond with the esp32.

I've been surprised how good the battery life is on the esp32-s2 so far, granted I'm not doing any bluetooth. The esp32 also has a deep sleep function that is surprisingly effective.

Your point on infrared sensor is well taken. I'm using LEDs in the visible spectrum during the prototyping because its easier to visibly troubleshoot. But I've tested with infrared as they use significantly less power.

I've thought a little about protecting the diodes. My thought was before I drill and ream the moderator I would install acrylic rods through the diode holes. That way when I drill and ream the moderator I would also be drilling through the acrylic. The advantage to this is when the acrylic gets dirty simply passing a cotton swab through the moderator should clean it off. I've not tried it yet though. Sometimes these ideas seems great in my head but need some adjustment in practice.

Also for those interested, I figured out my coding bug that was making the first shots report a little slow. When I initialize i load all my functions and libraries into memory so there is no delay when a shot is fired. I missed a library. So when a shot was fired the first sensor reported the shot, my code loaded an additional library which added a delay before the second sensors information could be recorded. Long story short I'm now preloading ALL my functions and libraries and the bug appears to be resolved.

 

[fe7565]

Interesting, I'll have to look at the NRF52. Do you know what its analog read speeds are? I had to add some circuity and amp to my photodiodes so they output digital because the analog read on the esp32 is so slow. I'm getting digital reads on the order of 1 microsecond with the esp32.

I've been surprised how good the battery life is on the esp32-s2 so far, granted I'm not doing any bluetooth. The esp32 also has a deep sleep function that is surprisingly effective.

Your point on infrared sensor is well taken. I'm using LEDs in the visible spectrum during the prototyping because its easier to visibly troubleshoot. But I've tested with infrared as they use significantly less power.

I've thought a little about protecting the diodes. My thought was before I drill and ream the moderator I would install acrylic rods through the diode holes. That way when I drill and ream the moderator I would also be drilling through the acrylic. The advantage to this is when the acrylic gets dirty simply passing a cotton swab through the moderator should clean it off. I've not tried it yet though. Sometimes these ideas seems great in my head but need some adjustment in practice.

Also for those interested, I figured out my coding bug that was making the first shots report a little slow. When I initialize i load all my functions and libraries into memory so there is no delay when a shot is fired. I missed a library. So when a shot was fired the first sensor reported the shot, my code loaded an additional library which added a delay before the second sensors information could be recorded. Long story short I'm now preloading ALL my functions and libraries and the bug appears to be resolved.

Maybe consider using a paired/matched digital infrared LED-diode ($2-4). This way you do not need any additional circuitry to process the signal. The max speed to sample with a timer a digital input signal on the nRF52840 is 16mhz You can use one digital input pin and run a counter (timer) on it at 16mhz. The timer will register the first data when the pellet passes the first LED-set and then timer counts the pulses until the second set of LEDs are passed by the pellet. Depending on the distance of your LED sensors, the resolution is about >1FPS at 1200 fps max pellet speed.

The ESP32 has good sleep currents, but are you going to wake it up before every shot, or going to run it continuously during a shooting session? The normal ESP32 uses about 100mA at lower CPU speeds (lower than 20mhz may give you some problems) and an additional 20-40mA added on using bluetooth. On the other hand, the ESPS32 has an extensive library/interface that makes programming easier.

 

[woogie_man]

The issues that the Daystate rifles had was the sensors would get dusted with lead dust and cause errors. You would have to remove the shroud and clean everything off and reinstall. It was honestly a pain in the butt to deal with.