Open Trickler: The DIY Smart Powder Trickler

[Ammolytics]

Looks like a fun project but according to your article it looks like it's not iPhone compatible yet. If so, any idea when?

Good question. I've started to jump through Apple's hoops, but this is the first time I've worked with their developer program. I can't make any promises about how long it will take.

I did file a ticket to track this, in case you want to follow along there and be notified of updates.

 

[itchyTF]

I imagine there are a lot of members here and elsewhere that have Apple devices. I'll be anxiously waiting.

 

[Bill K]

Does look interesting, but why all the work when the new auto charge powder measures from RCBS, Hornady and others do the last few grains with a built in trickle mode to top off charges ?

 

[Ammolytics]

Does look interesting, but why all the work when the new auto charge powder measures from RCBS, Hornady and others do the last few grains with a built in trickle mode to top off charges ?

Good question. The limiting factor for the RCBS/Hornady/etc machines is the quality of the scales they use -- they simply aren't precise or accurate enough to achieve the consistent, to-the-kernel throws that competitive marksman are after. The lab-grade scales from A&D, Sartorious, and others are capable of 0.001gram/0.02grain measurements without suffering the severe drift that you'll experience on lower-quality scales.

Some of the F-Class and Benchrest shooters in my local club have started to refer to the ChargeMaster as the ChargeApprentice.

The other problem that I have with them is the rotating trickler tube. In my experience, this design works well for throwing a lot of powder fast, but is incapable of dropping a single kernel at a time with any consistency. The powder is rolling over itself inside the tube, piling and clumping, and inevitably those piles will fall over and pour out at the worst-possible time, leading to an overthrow.

Hope this helps to answer your question!

 

[Bill K]

I understand your point.. Good thought.

 

[itchyTF]

I just looked at your video. It appears that the system is really slow as it approaches the target weight. Why not control the motor speed using PWM rather than On/Off? I realize PWM is actually On/Off but at a higher frequency which gives the effect of always On but at an adjustable speed. Also, having a long drop path might require a slow response. Otherwise the scale would be stabilizing the last kernel dropped while another is enroute (if it was faster). So, it seems if the drop distance was shortened the system could be sped up.

 

[Ammolytics]

I just looked at your video. It appears that the system is really slow as it approaches the target weight. Why not control the motor speed using PWM rather than On/Off? I realize PWM is actually On/Off but at a higher frequency which gives the effect of always On but at an adjustable speed. Also, having a long drop path might require a slow response. Otherwise the scale would be stabilizing the last kernel dropped while another is enroute (if it was faster). So, it seems if the drop distance was shortened the system could be sped up.

It's true that it's a bit slow in the video, and believe me, you're not the first person to bring it up (even in this thread -- see my earlier reply).
Thanks for the suggestion about the PWM! That's a reasonable suggestion which I may try with a future iteration. For now, I'd like to try a PID Controller, which I believe is applicable to this specific problem.
You can read more about it on the ticket I have open for this.
https://github.com/ammolytics/projects/issues/15

 

[dcali]

Interesting project. I’m about half way through something similar. I’ll post some pictures once I get something worth looking at working.

 

[Ammolytics]

That would be great.

Thanks

I wasn't able to get around to soldering the other boards like I had hoped. In the meantime, the following photos may help.
It's also worth noting that the Adafruit proto board isn't like normal perf board. It's designed specifically for the Raspberry Pi GPIO pins and it has some existing connections that make it behave more like a solderless breadboard.

Edit: I tried embedding the photos but they ended up being blocked. Here's a shared album instead.

 

[itchyTF]

The description of the vibration motors states the rated working voltage as 1.5v but goes on to state -

• Rated Voltage: 1.5V, Rated Speed: 8000RPM; Rated Voltage: 3V, Rated Speed: 7000RPM; Rated Voltage: 3.7V, Rated Speed: 9500RPM

Does that mean it can tolerate up to 3.7v without damage? Also the 3v speed doesn't make sense.

 

[Ammolytics]

The description of the vibration motors states the rated working voltage as 1.5v but goes on to state -

• Rated Voltage: 1.5V, Rated Speed: 8000RPM; Rated Voltage: 3V, Rated Speed: 7000RPM; Rated Voltage: 3.7V, Rated Speed: 9500RPM

Does that mean it can tolerate up to 3.7v without damage? Also the 3v speed doesn't make sense.

Good questions! I'm not sure I can vouch for the accuracy of the product description. All I can tell you is that I've used these motors a bunch with 3V, loading hundreds of rounds and have yet to burn one up. That said, you can use whatever motor you choose! The point of the Open Trickler is that you can customize it however you want -- the components I linked to are simply a reference of what I happened to choose, but it's by no means prescriptive.

 

[ebb]

Lost sound at 31 seconds is it me? Started over 3 different times and no sound at 31 .

 

[Ammolytics]

Lost sound at 31 seconds is it me? Started over 3 different times and no sound at 31 .

I had an issue in editing where one of the sound channels cut out. As long as you're using stereo speakers, you should be able to hear it in at least one of them. (Sorry about that, I'm still learning when it comes to video editing -- it's harder than it looks)

 

[itchyTF]

FWIW, The Dandy's slow speed uses 1 battery and fast uses 2 batteries in series so apparently it's a 3v motor.

 

[Frost1235]

How well would this work with another scale? I have a scientech I am considering trying to do the same thing.

 

[Ammolytics]

How well would this work with another scale? I have a scientech I am considering trying to do the same thing.

Great question! It *can* work for other scales, but you'd need to write some code to support it.
This line of the trickler.js file is where it uses the code which is for the A&D scale.
https://github.com/ammolytics/projects/blob/develop/trickler/peripheral/lib/trickler.js#L7

This file provides support for the A&D scales (which the user manual documents).
https://github.com/ammolytics/projects/blob/develop/trickler/peripheral/lib/and-fxfz.js

I don't know what model of Scientech scale you have, but page 9 of this user manual defines the RS-232 interface.
https://scientech-inc.com/media/downloadable/files/links/s/1/s12k_im-d_1_.pdf

Hope this helps (and isn't too overwhelming)!

 

[cyclepath37]

Any recommendations on the best way to control this with something other than a phone with bluetooth? Were the folks running it with an omega have success or any struggles? I have an A&D hr202i with an omega two speed, and am very interested in building this system. Thank you

 

[Ammolytics]

Any recommendations on the best way to control this with something other than a phone with bluetooth? Were the folks running it with an omega have success or any struggles? I have an A&D hr202i with an omega two speed, and am very interested in building this system. Thank you

Controlling it with anything other than the provided mobile app is out-of-scope. I toyed with the idea of button/knob interfaces, but kept coming back to the same conclusion -- everyone has an advanced remote control with infinitely configurable interface in their pocket.

All of my code is open-source, so you're welcome to reuse and adapt it as needed for you own build!

 

[cyclepath37]

Makes sense. Thank you for sharing the project.

 

[Ammolytics]

Quick update: A lot of progress has been made on the OpenTrickler project over the past couple weeks (holiday vacation).

- An iOS app is ready for testing (PM me your iOS email address if interested)
- A ready-to-go microSD image can be downloaded and flashed
- The OpenTrickler code lives on a FAT-32 partition, allowing the microSD card to be used as a USB drive. You can tweak the program from any computer (Windows, Apple, Linux)
- If you set it up with WiFi, you can view the OpenTrickler debug and system logs from your web browser

It was a ton of work getting to this point. I learned a lot of new things along the way and I feel very proud of the progress that's been made.