Is there a cheap and small electronic component that generates enough heat to draw on thermal paper? I don't need to draw fast or precisely, I just need it to be able to produce enough heat to "activate" the thermal paper. The best would be something that could work on 12VDC at most. I'm sure there is such a thing, but I just don't know what it is. Any help is greatly appreciated, HEMOglobina
I seem to recall drawing on thermal paper (Costco receipts) with my fingernail. Have you tried that?
Jon
Back in the Dark Ages there were chart recorders that graphed onto thermal paper. Whereas "normal" chart recorders used a big meter movement with a pen where the tip of the needle would have gone, the thermal jobs just used a hot wire stretched between 2 supports at the tip. The thermal paper traveled over a ridge, so presenting only a narrow surface where the wire contacted. The paper was drawn over the ridge (and thence across a flat surface where it could be seen) by a geared paper feed.
A similar idea might work for you. If you want X-Y instead of a time base, you'd have to servo the paper handler.
Best regards,
Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis
--- Get a 12 ohm 1/4 watt resistor (around 12 ohms, nothing critical) and bend one of the leads backwards so that the ends of both leads face in the same direction. Make the bend semicircular and as close to the end of the resistor as you can, while keeping the bend nice and smooth, since that's what you'll be drawing with.
Next, cut the lead on the opposite end of the resistor to about 1/8" in length and solder an insulated wire to it long enough to go to the power supply you'll be using to heat up the resistor when you draw. Solder another wire to the end of the lead wire with the curve in it.
Next, get a lead pencil and push out the lead.
If the resistor will fit in the hole where the pencil lead used to be, then push the ends of the wires through the hole and epoxy the resistor in place in the hole.
If it won't fit, drill out the end until it will, snugly, and then pull it into place with the wires and epoxy it in place.
Finally, connect the wires to the supply and increase the voltage until the bent wire gets hot enough to daw with.
Voila! Hot pencil!
Or, you could use a soldering iron and a variac...
--- JF
A resistor?
if you're happy with much less than 12v then a piece of nichrome wire, eg salvaged from a dead toaster or hairdryer, or if you can't find some nichrome a piece of fine stainless wire (eg from the spring in a 3.5" floppy) 1.2V might even be too much,
-- ?? 100% natural
For nichrome, just search ebay.
Cheers! Rich
Anyone know why thermal paper fades over time?
Andy
Because it isn't intended for long term use. Heat will turn the paper black. When I pick up a pizza and they stick the receipt in the edge of the box, it is completely black by the time I get home. The chemical process is rsponsible, and the intended use of thermal paper was for a cheap printout.
The special thermal paper for chart recorders had a coating that was melted to expose the darker background color of the paper.
-- For the last time: I am not a mad scientist, I'm just a very ticked off scientist!!!
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