View Full Version : Things you can do with 4 props

Peter Jakacki
01-17-2008, 09:06 PM
I am in the final throes of commissioning a new design based around four propellers. The unit is a 12 channel tablet grader/counter that measures the transition times and shadows of various sized tablets/pills as they spit past the sensor window. Since the unit has to grade and fill two bottles in under a second I wanted to make sure I had enough steam available to drive the prototype so I dedicated a propeller to each of 6 sampling channels plus one for control/coms and one for I/O. This unit is a lot cheaper than many units which employ PC based vision systems and it's also more fun.

The result?

Control Propeller
RS-232 Console coms
Optional XPORT ethernet coms
Local coms to slave solenoid controller
Dual coms to slave sensor propellers
RS-485 PLC coms
spare RS-485
SD CARD for logging plus firmware upgrading
VGA + keyboard

Solenoid Propeller
12 solenoid outputs
4 extra OC outputs
24 gate switch inputs for verification

Sensor Propellers (x2)
MCP3208 12-bit ADC (x2)
Photosensors (x12)
Individual infrared LED modulation

I still have a little work to do but it is now functional although the controller propeller has run out of cogs but once I get my dual-port coms object working 100% I should be back in business.

BTW, the touch screen is a commerical product that interfaces to the PLC but there is no reason why the propeller couldn't do something similar.


www.pbjtech.com/cpu/propeller/tabetcounter-m.jpg (http://www.pbjtech.com/cpu/propeller/tabetcounter-m.jpg)
www.pbjtech.com/cpu/propeller/TX-RX-m.jpg (http://www.pbjtech.com/cpu/propeller/TX-RX-m.jpg)
A gentle run test:
www.pbjtech.com/cpu/propeller/tabletcounter-m1.avi (http://www.pbjtech.com/cpu/propeller/tabletcounter-m1.avi)

01-17-2008, 11:00 PM
Hi Peter, the .avi video clip link provides some insight, but I still don't get what you're trying to do here. Are you trying to sort two (or more) different types of pills into two bottles? Hmmm... The parallel nature of your product is a bit perplexing. Traditionally machine sorting puts product through a high-speed gravity or belt-driven stream and after detecting differences in product uses a puff of air to sort them into different channels. Puffs of air are seemingly more reliable (if not faster) than mechanical solenoids for routing small parts over millions of selections. Perhaps you can explain further what you're doing without giving away any proprietary info.

I'm impressed...

Best Regards, David

Fred Hawkins
01-17-2008, 11:00 PM
Peter, your .avi doesn't seem to be right. ms media player sees it as an audio file.

01-17-2008, 11:16 PM
Hi Fred,

I avoid Windows Media Player like the Plauge... Peter's .avi file plays fine in the free and open VLC Media Player www.videolan.org/ (http://www.videolan.org/). I haven't tried Peter's .avi in Windows Media Player, nor will I. VLC runs most everything I throw at it and it's been quite secure to-date (no "phoning-home" like WMPlayer).

Regards, David

Oldbitcollector (Jeff)
01-18-2008, 12:06 AM
If he's in the Propeller contest... I haven't got a prayer... :) AWESOME WORK!


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A Living Propeller FAQ - The Propeller Wiki (http://propeller.wikispaces.com/)
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01-18-2008, 12:16 AM
AVI plays fine in WMP10 http://forums.parallax.com/images/smilies/wink.gif

Looks real interesting Peter, well done.


www.norfolkhelicopterclub.co.uk (http://www.norfolkhelicopterclub.co.uk)
You'll always have as many take-offs as landings, the trick is to be sure you can take-off again ;-)
BTW: I type as I'm thinking, so please don't take any offense at my writing style http://forums.parallax.com/images/smilies/smile.gif

Peter Jakacki
01-18-2008, 06:36 AM
I divx'd a clip so it wouldn't be too large a file to download but WiMP will sort of play it if it has the divx codecs although it seems to want to go blank towards the end of the clip. I use the free DivX Player which works without wimping.

The video is just a quick clip of a manual test of a tablet counter counting tablets of various sizes which should all be one size per batch but some may be stuck together and some may be chipped. Since there are regulations that govern these industries it is important that bottles have exactly what they are supposed to have. Sometimes the pills are expensive so you don't want to be giving any away either.

In normal running mode the tablets are coming down thick and fast and the filled bottles would be on a conveyor belt and gated away. As the bottle starts to fill, the counter starts to shut off gates to prevent an uncontrolled spill. The feed belts will slow down and then when the remaining bottle is filled the bottles will be gated away etc then the tablets that are sitting on the gates (which have been precounted) are dropped into the new bottles and the belts are sped up again. All this happens very quickly and there are all kinds of other conditions of course and gating delays and whatnot.

The thing is that many things I design don't normally go clickety-clack whirr-whirr and there is a certain amount of satisfaction involved when you see it operating.

Hey Oldbit, if I was going to enter the contest I think it would be with something mechanical, like a little security robot perhaps :) But don't let that put you off as we all learn off each other and it's not the big things that count, they might be impressive, but it's the little things that everyone can benefit from that prove to be the real winners.


01-19-2008, 11:28 PM
Very impressive.