DIY Powder Dispenser

[sdupontjr]

I've been getting several DM's about my auto dispenser, so I figured I'd do a write up on it with a material list.

I was looking for an auto dispenser a while back and everyone that I saw had some sort of issue with it or it was way too expensive. As an engineer, I like building things so figured I'd tackle this one.
The dispenser works off time. There is a control board that has settings in which you can control time. In that case the board also has a COM, NC (normally closed), NO (normally open). This board allows you to control 1 single motor with the help of a simple voltage regulator. The second board in the picture is for controlling the slow speed and kill power portion of the wiring. I'll explain as we go along.

This is the ultimate goal. A dispenser that holds over 1 lb of powder, needs no warmup time, and will dispense powder in a pretty fast setting so you're not waiting. The one difference with this rather than the digital "all-in-one" RCBC, Honady, etc, is that the digital units have an approach to weight feature. It allows the motor to spin up to a certain weight settings then start slowing down. This is not like that. If you overshoot your weight, take off time. If you under shoot weight, add time. Once you get close, the beam will trigger the optical sensor and kill power.







Material list:

Here is a list of everything that I used. I already had some switches but they can be bought anywhere for cheap. I

12v Relay Module

AEDIKO 4pcs DC 12V Relay Module 1 Channel Relay Board with Optocoupler Isolation Support High or Low Level: Amazon.com: Industrial & Scientific

Junction Box

Amazon.com

Timer Relay

Amazon.com: UCTRONICS DC 12V Programmable Time Delay Relay Module with Metal Enclosure, On Delay and Off Delay Timer for Automobile, Raspberry Pi, Industrial Control, and Other Automatic Control Projects : Automotive

Speed Controller

https://www.amazon.com/RioRand-RR-P...B00N30UK2M&psc=1&ref_=pd_bap_d_grid_rp_0_46_t

Clear Hopper

Amazon.com

Motor 350rpms and mount

350 RPM Premium Planetary Gear Motor - ServoCity®

1302 Series Clamping Hub (22mm Bore)

Welcome to ServoCity where you can get the parts you need to bring your ideas to life! From servos to switches, from actuators to Actobotics, we work hard to bring you the best components backed by unparalleled technical support

www.servocity.com

Brass Tube

Amazon.com

4mm to 5/16 Coupling

0.3125" to 4mm Set-Screw Shaft Coupler

Welcome to ServoCity where you can get the parts you need to bring your ideas to life! From servos to switches, from actuators to Actobotics, we work hard to bring you the best components backed by unparalleled technical support

www.servocity.com

NPN slotted sensor EE-SX 676PWR

5-24VDC NPN/PNP Slotted Optical Switch Photoelectric Sensor With 1 Meter Cable | eBay​

Slotted Optical Switch 5MM Photoelectric sensor DC5～24V 100mA. EE-SX670-WR NPN Light Up when Power on. EE-SX671-WR NPN Light Up when Power on. EE-SX672-WR NPN Light Up when Power on. EE-SX673-WR NPN Light Up when Power on.
www.ebay.com

2” to ½” reducer (the kind that tapers like a funnel

Amazon.com: Lesso America 429 Series PVC Pipe Fitting - Reducing Coupling - Schedule 40 (White) - 2×1/2" (SOC x SOC) / High-Flow Capacity/Plumbing, Irrigation, Pool, Spa, DIY Projects/NSF Certified (429-247) : Industrial & Scientific

Amazon.com: Lesso America 429 Series PVC Pipe Fitting - Reducing Coupling - Schedule 40 (White) - 2×1/2" (SOC x SOC) / High-Flow Capacity/Plumbing, Irrigation, Pool, Spa, DIY Projects/NSF Certified (429-247) : Industrial & Scientific

www.amazon.com

Switches ( I had these already, but very cheap) on/off main power switch, on/off cycle switch, the white button is a Mom on / off push button switch. It is used to bump or trickle.

 

[sdupontjr]

Now that you have the parts list, lets build. I like using the WAGO electrical connectors. You can glue them to your lid, but the flip up features of these connectors allow you to test and not damage the connector.

You have the wiring diagram.


The motor bracket is just some aluminum angle I had lying around.



I like this junction box for the fact that is has the grid in the bottom. It allows you to screw and munt all your items to it so nothing rattles.



For the 2" to 1/2" reducer, I cut the length of the 1/2" side off some so that it wouldn't stick up through the lid so much. Cleaner look. Had some sheet metal lying around, so made some angle brackets to support it. I plugged off the 1/2" side with a piece of plastic followed by a 1/2" piece of pvc pipe. Thus giving it a solid slick floor.

 

[sdupontjr]

Alignment is key. I measured the height of the center line of the coupling and then scribed it on the funnel. Drill the hole and feed the tube through. What I did was chuck the tube in my drill and run it back and forth to open it to fit. it will squeak some. To fine tune it, I took my small chainsaw file and lightly deburred it so that it would still seal but not squeak. This is key because if the gap is too big, smaller ball powders will leak out.

You can see the small gray piece of plastic that I glued in for the floor. The aluminum tubing was used but I eventually swapped to brass because the brass had a thinner wall thus larger ID.


I measure the placement of the funnel so it would pass though. I cut this opening and fine tuned with my dremel burr bits. Again, wanted a clean look.




This is simply spacing and placement of the switches to get them to fit. the WAGO fittings are super glued on the top so they do not move.


The funnel will stick up alot higher through the top, I cut mine down for again, cleaner look.

 

[sdupontjr]

I took the end of it and with a sanding attachment on my dremel, tapered it. So that when I turn it over to dump or change powders, kernels wont get hung up.



I took some clear tape and wrapped the end to give it a snug fit in the reducer. I didn't want to glue it because it makes cleaning easier.


For changing powders, I usually tilt forward and dump the brass tube or aluminum tube 1st. Then place my finger over the tube and dump the main hopper back in container. You may have to dump the brass tube a few times during this process. Once the last few kernels or in the bottom of funnel, I remove the clear hopper and now dump the rest.

Very slick setup. I use a charlotte PVC fitting for the top.

 

[sdupontjr]

One key thing to remember is don't drill your hole too big in the brass tubing or it would feed the powder good enough. I also added some adjustable feet with felt so that it can be fine tuned even further bay tilting it up or down for faster or slower dispense speed.

The scale is an older RCBS 502. The older scales work best according to Scott Parker. He tuned this one that I found on ebay.


The sensor that the beam breaks is mounted on another piece of aluminum angle that is screwed to the frame of the scale. The holes for the sensor are slotted so that the sensor can be adjusted to where you want the final outcome to be. I like it to fall short about .5g so that I can bump to exact setpoint. But you can choose whatever you like.

Here is my older unit running so you get the idea.

I tied the sensor on the scale to an ethernet cable. So that I can detach it and store the scale seperatly when not in use. I cut a hole and set up an quick connect for it. You can see it on the top side of the box. So the female side is hard wired in the box and the male end is on the scale. Simple plug and play.



I also wired in a plug for the 12v power. So there is no cord hanging off this as well. Unplug the power adapter and roll it up also.



I also have been getting questions about having a digital scale. This system will work with your digital scale as well, but you won't have the auto stop feature. Remember the system works on time. So for 49g of varget sample, I set to 7. It runs at 350 rpms for 7 sec then the relay swaps state and goes through voltage reg to which its like a crawl. But being the VR is adjustable, you can set that crawl speed to whatever you want. I like it very slow, like an auto trickle. Then the beam breaks the optical sensor and stops the unit. YOU MUSY REMEMBER TO TURN OFF THE CYCLE SWITCH BEFORE REMOVING THE PAN OF POWDER. Not power switch, the cycle switch. remove pan, place pan back, flip cycle switch and it starts again.


For those that use digital scales, you don't need the voltage reg, optical sensor or second relay. You simply set you time and it will dispense powder for that time allotment. then you would have to manually trickle or use some sort of trickler to get to your desired setpoint. But by setting the timer slightly lower, you'll never overthrow a charge. The key feature of the voltage reg is that it can control the speed. So trickling is very slow and controlled. if not used, trickle speed will be trying to bump 350rpms.


Hope this information helps and I'm sure those that try it will have more questions.

 

[Castle Rock]

Great, thank you for taking the time to explain it all

 

[sdupontjr]

Oh forgot one other thing, I have Varget, 8208xbr, H1000, 4831sc, TAC and Trailboss. The only one I haven't tried in it yet is trailboss, but I would assume it would do just fine. But I only use in it my subs for 308. Not sure if tumbling them would bust them up. I like the case fill with it so I use a dipper for my subs.

 

[BigE]

I appreciate you sharing for the wider audience. Was interested from the first post in the other thread.

 

[Firth]

I'd wondered if there was any extra logic regarding start/stop as it gets close, but it sounds like it pretty much runs at max on a timer, then slows down after a specified time, then trickles until the optic senor stops it. Is that accurate?

 

[sdupontjr]

I'd wondered if there was any extra logic regarding start/stop as it gets close, but it sounds like it pretty much runs at max on a timer, then slows down after a specified time, then trickles until the optic senor stops it. Is that accurate?

yes. I tried several different control boards and none could do what I wanted to do. They would always overthrow. Well in doing this, it was all about time. If the unit is constantly over charging, then thats now value added. So time because the factor. Another thing to consider was my very 1st build had 2 motors.

1 for fast dumping, then a second for tricklin. The second was purely manual. But this particular board changes state, so you can control 1 motor from 2 different inputs. Thus a 12v input and an adjustable input through the voltage reg. So the new system and this board controls 1 motor at 2 different speeds. but still there was not stop, no cutoff. Thus the optical sensor.