Started a new reloading room project - I've set out to build my own automatic powder dispenser/trickler.
My proposed architecture is as follows; electronic balance communicating with a Raspberry Pi - I will enter my target charge with buttons & LCD screen or an apache web server interface. I will have two methods of dispensing powder; an auger-based system for dispensing 90% or so of the charge, driven by a stepper motor, in combination with a motor-driven powder trickler to finish it off.
First thing I did was source a balance that measures in grains, has resolution equal to or better than .1 grains, and has a data output line that I could tap into. There are a lot of high priced scientific balances that meet the criteria, but I didn't want to blow the budget on the first piece of equipment. I ended up with this -
http://myweigh.com/product/ibalance-401/
Next, I started playing with the Pi. I am using Python for this project - I have done SOME programming in C, but it has been 8 or 9 years. Needless to say learning python is a slow process. I have succeeded in receiving data from the scale, interpreting it, and lighting up LEDs which represent the two motors driving the dispensers.
(Note the custom gender changer and null modem - its a work of art)
I have begun designing the auger side of the dispenser/powder hopper in CAD. My original concept used a drill bit inside a tube as the auger. I have recurring nightmares about sparks/heating and quickly dropped the drill bit idea. My current plan is to 3d print the auger and housing to meet my needs. I figure I can also fine tune the auger/tube/hopper this way.
A 3d printer is in my future... driving the total cost for this project to at least double (and maybe triple) the cost of an off-the-shelf solution. The printer will get continued use well beyond the scope of this project so I am not sure I can consider it part of the cost. I am simply 'charging it to the job.'
My immediate challenge is choosing a 3D printer. After that? On to the auger/trickler and drive system for the stepper motors.
This guy has the right idea, but I don't want to sit in front of it and dump powder in manually. My goal is to 'walk away,' so to speak, and continue with other reloading operations while my dispenser handles the rest.