Choosatron: The Printening

July 25, 2012

One frustration I’ve run into with this project is the different power requirements my components have needed to work nicely. 12 volt, 9 volt, 5 volt, plus inconsistent amperage requirements. The thermal printer takes almost no power until you ask it to print, when it spikes to 1.5amps! Most of the other components don’t take too much; probably 300-500ma combined as a rough guess. I determined that I’d need a minimum of 2amps to power everything appropriately. 1.5 reserved for the printer and 500ma for everything else. The coin acceptor was the first annoyance since it wants 12v and the supplies I had were all 9v. I ended up finding many 12v power supplies ranging from 2-3amps that were for external hard drives so perfect! Except, after I get the coin acceptor power how do I get the printer what it needs?

Insert coins printout

Voltage Regulator

12v to 9v w/ 3amp Output

I kept looking however, and found exactly what I was looking for. 12v to 9v, and 3amps output! There was a 2amp output as well, but since I found a 12v 3amp power supply I might as well be able to support it. This part was only available in China, but cheap so I purchased. It took 3-4 weeks until it finally arrived! I had gotten the L7809 regulators and verified that they did in fact work as advertised. Hooked it all up, printed, and got a faint lettering due to the lack of power. Just days ago I got the part I was really waiting for! It had been such a long wait I had already started doubting it would fix my printing problems. I had played around with running the printer on 12v, but it would print a little too fast, and though it was darker than with the small regulator, it wasn’t good enough and I didn’t want to hurt the printer.

Well, I plugged the new voltage regulator in, fired up the Choosatron, and wow…after all the hours with both the hardware, and programming the software, FINALLY seeing it truly work! Beautiful, rich text. Take a look below! Just in time too as I’m planning on bringing it by an Arduino group meeting this coming Thursday.

I also completely finished the points feature, getting continues fully supported (if ending quality 1-4 of 5, insert a coin to continue, get prompted for how many choices back you want to move), as well as authors getting to set what a ‘perfect score’ is, along with a ‘continue penalty’. Phew! So much awesome stuff. The writing guide is finally online, along with a test story I wrote to help people get started. Take a look here!