Making a pen plotter?
MarkS
Posts: 342
I'm a commercial bus driver. Since I drive all over the country, I must (by law) fill out a daily log. The issue is that the company I work for just switched log books to one made by JJ Keller. Keller made some software that scans the log into a computer and notes the driver's daily activity. I've been using computers since I was eight. I taught myself several programming languages and am very familiar with the hardware. While it is possible to scan anything into a computer and write software to interpret the data, there is no way, with the technology we currently have, to interpret it with any degree of accuracy. This has quickly become a nightmare.
What I want to do is to make a small pen plotter that will plot the data I enter on the log. The software would be easy to write and I'd probably use a Propeller, but the hardware is not too simple. I'm assuming that this could be done with a couple of small servos and a spring / actuator combination to raise and lower the pen. It would be a small CNC machine with low accuracy. Does anyone have experience with this? We're talking small here, no more than 12" x 12" (less is preferred) + the height of the base and pen.
What I want to do is to make a small pen plotter that will plot the data I enter on the log. The software would be easy to write and I'd probably use a Propeller, but the hardware is not too simple. I'm assuming that this could be done with a couple of small servos and a spring / actuator combination to raise and lower the pen. It would be a small CNC machine with low accuracy. Does anyone have experience with this? We're talking small here, no more than 12" x 12" (less is preferred) + the height of the base and pen.
Comments
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- Stephen
What I want to do is make a small gantry that holds a ball point pen. The pen is raised or lowered (z-axis) by some sort of mechanism, probably a spring and actuator combo (it just needs to be either up or down, with no in between positions) and the gantry is moved in the X and Y axis via small steppers or servos. The mechanical part is what I'm going to have trouble with. I'd suspect that a full size CNC mill would be easier to make due to the size difference.
What would be a quick, easy and cheap way to do this? I've seen that DIY CNC site, but his methods will be incompatible due to the size differences.
-Phil
Not in this case. The log has to be filled out as the work is performed, so copying a printer mechanism will not work. The pen must move to various parts of the paper at different times, and while the accuracy is not at the level of a CNC mill, it needs to be about the width of the pen stroke. The biggest part of the log, and the most important, is a graph showing changes in types of types of service (driving, off duty, on duty not driving and sleeping). This graph is divided to to 24 hour segments, and each segment is divided into 15 minute intervals.
Here is a scan of the log (sorry for the size):
Here is what a completed graph would look like:
Post Edited (MarkS) : 1/2/2008 6:59:26 PM GMT
The pinch roller I'm referring to is bi-directional, unlike that of a printer mechanism. It's a common feature in pen plotters of all sorts. But even then, if you fed the paper from the side, wouldn't a unidirectional mechanism be sufficient?
-Phil
-Phil
Probably the older small (8.5 x 11) format HP pen plotter might work for you.
Heres one on ebay: http://cgi.ebay.com/HP-7475-A-PLOTTER-PRINTER-w-PENS-VINYL-CUTTING-7475_W0QQitemZ150199934164QQihZ005QQcategoryZ46723QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Just do up a sketch of the form in AutoSketch (or some other low cost CAD software), adding data as required and plot it out.
Cheers,
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Tom Sisk
http://www.siskconsult.com
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-Phil
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There's nothing like a new idea and a warm soldering iron.
Lets say that one hour on that sheet is half an inch.
Now picture four rubber wheels (two each side) feeding that paper at one half inch an hour.
Slowly dragging a weighted pen over the surface.
As your state changes just manually slide the pen left or right to the correct position.
Maybe have four notches that line up with each of your four states.
Crude example sketch attached.
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- - - PLJack - - -
Perfection in design is not achieved when there is nothing left to add.
It is achieved when there is nothing left to take away.
Post Edited (PLJack) : 1/9/2008 1:15:52 AM GMT
also, how much effort putting it together and re-thinking the wheel?
not to mention the programing
You can buy a used 12" plotter used in the sign making industry,
that can use a knife or a ball pen.· (adjust the weight)
make your own font (hand written)
make a template in Word, as you enter the data, press print; put in a new sheet and
see it appear on the plotter. Just remember to select the hand writen font you created.
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Fernando Gomez
Never compare yourself with anyone else, there will always be someone bigger·or·smaller·than you.