You know how sometimes you just can’t resist collecting old hardware, so you promise yourself that you will get around to working on it some day? [Danny] actually followed through on one of those promises after discovering an old Radio Shack TRS-80 TP-10 thermal printer in one of his boxes of old gear. It looks similar to a receipt printer you might see printing receipts at any brick and mortar store today. The original printer worked well enough, but [Danny] wasn’t satisfied with its 32 character per line limitation. He also wanted to be able to print more complex graphics. To accomplish this goal, he realized he was going to have to give this printer a brain transplant.
First, [Danny] wanted to find new paper for the printer. He only had one half of a roll left and it was 30 years old. He quickly realized that he could buy thermal paper for fax machines, but it would be too wide at 8.5 inches. Luckily, he was able to use a neighbor’s saw to cut the paper down to the right size. After a test run, he knew he was in business. The new fax paper actually looked better than the old stuff.
The next step was to figure out exactly how this printer works. If he was going to replace the CPU, he was going to need to know exactly how it functioned. He started by looking at the PCB to determine the various primary functions of the printer. He needed to know which functions were controlled by which CPU pins. After some Google-Fu, [Danny] was able to find the original manual for the printer. He was lucky in that the manual contained the schematic for the circuit.
Once he knew how everything was hooked up, [Danny] realized that he would need to learn how the CPU controlled all of the various functions. A logic analyzer would make his work much easier, but he didn’t happen to have one lying around. [Danny] he did what any skilled hacker would do. He built his own!
He built the analyzer around an ATMega664. It can sample eight signals every three microseconds. He claims it will fill its 64k of memory in about one fifth of a second. He got his new analyzer hooked up to the printer and then got to work coding his own logic visualization software. This visualization would provide him with a window to the inner workings of the circuit.
Now that he was able to see exactly how the printer functioned, [Danny] knew he would be able to code new software into a bigger and badder CPU. He chose to use another ATMega microcontroller. After a fair bit of trial and error, [Danny] ended up with working firmware. The new firmware can print up to 80 characters per line, which is more than double the original amount. It is also capable of printing simple black and white graphics.
[Danny] has published the source code and schematics for all of his circuits and utilities. You can find them at the bottom of his project page. Also, be sure to catch the demonstration video below. Continue reading “Thermal Printer Brain Transplant is Two Hacks in One”
[Hubert] sent us a tip about a friend’s project to rescue a laundromat from its failing electronics. We’re not entirely sure what went wrong with the old control center, but considering a replacement would have cost nearly 25,000 EUR, we think [Stefan] found the perfect solution: he gave it an Arduino and Android overhaul (translated).
Although [Stefan] explains that the boards were defective, perhaps one of our German readers can help us out with a more specific translation. More clear, however, are the steps taken to upgrade the system. The situation at the laundromat was a bit of an emergency: there was no way for customers to pay for use of the machines. As a result, [Stefan] had free reign to overhaul things as he saw fit. He decided to remove the complex button setup in favor of a touchscreen Android tablet, which provided users with a simple interface to make selections. The tablet serves only as an input device. The heavy lifting is handled by an Arduino Mega 2560, which hooks up to what remains of the original system and controls the 27 machines in the laundromat.
[Stefan] admits that he isn’t a particular fan of the Arduino, but that for the price, it’s a tough solution to beat. He’s not the only one overhauling with Arduinos. Check out some other examples of upgraded machines, like the Arduino-enhanced PopCARD vending machine.
UPDATE: [Andreas] sent in a better translation of the project page which we’ve included below. He worries his written English isn’t the best, but we think it is a lot easier to understand than the machine translation. Thank you for you work [Andreas!]
Continue reading “Running a Laundromat with an Arduino”
There is buzz all over the reddits and Element 14 discussion boards about an updated version of the Raspberry Pi that bumps the amount of RAM from 256 MB to 512 MB.
This new update comes after the announcement of an upgraded version of the yet-to-be-released Raspi Model A (from 128 MB of RAM to 256 MB), and a few slight modifications to the Model B that include fixing a few hardware bugs (nothing serious) and adding mounting holes.
After perusing the Element 14 and Raspberry Pi discussion boards, a few things become apparent. Firstly, it appears this new upgrade to double the amount of RAM was initiated by manufacturers. It seems 512 MB RAM chips are cheap enough now to include in the Raspi without impacting the cost of components. Secondly, 512 MB seems to be the upper limit for the Raspberry Pi, at least for this iteration of hardware. Not enough address lines, they say, but you’re welcome to try and hack your own RAM to a Raspi CPU.
So far, attentive Raspi enthusiasts have found Raspberry Pis with double the amount of RAM on the UK Farnell site and the Australian Element 14 site. Nothing so far on the US Element 14 site, although we’ll gladly update this post when a Hackaday reader finds the relevant link.
EDIT: Here’s the link for the US version of Newark. No, there aren’t any in stock. Also, Hackaday beat the official Farnell/Element 14/Newark press release and the Raspberry Pi blog to the punch. Woo, go us.
[Paul] spent his summer bringing an iMac G3 into this decade. There’s plenty of room to work with since he removed the CRT which originally occupied most of the computer’s space. The final project is much more powerful and since he preserved most of the metal mounting parts inside it remains quite strong.
He started by swapping flat screen monitors with his Grandma (who incidentally runs Linux… nice!). She had a 15″ model which would fit nicely in the case so he upgraded her to 17″ and took the old one. With bezel removed it fits perfectly where to old tube had been. Next comes the power supply. It’s mounted on the bracket which held the back of the tube, with a bit of metal removed to clear the air intake. To mount the motherboard he fabricated a bracket at one end where the iMac’s stage drops away. In retrospect he wishes he had rotated the board to make the I/O panel more accessible. The hard drive mounts on the original carriage, and he did some creative gluing to make his replacement DVD drive align with the original optical drive opening. The finished product looks great from the front and sides, with the cables running out the back as the only indication that it’s had some major work done on it.
[Simon] had a Rockford Fosgate Punch 601s amplifier in his car, and while it was a great piece of equipment, he wanted a little more power behind his stereo system. It turns out that with just a handful of parts and a bit of soldering work, he was able to increase his amplifier’s output by 200 watts, putting it on par with a Punch 801s.
The main board in each amp is laid out identically, making the conversion a relatively easy process. A handful of MOSFETs need to be added, along with some resistors and capacitors. Most of the work can be done with a decent soldering iron, though you might want a hot air reflow station to handle the smaller resistors – it all depends on your skill set.
We’re really not sure how big the price difference is between the two amps, but we’re pretty certain that the conversion would be worth it. [Simon] sells conversion kits on his web site for under $60, but you may be able to find the parts for a bit less if you hunt around.
[Heli] had a WRT300N wireless router sitting around collecting dust. He decided to squeeze at bit more entertainment value out of it by seeing if he could pull off a RAM upgrade. He managed to double the router’s RAM and posted a walk through (translated) to help you do the same.
Swapping out surface mount RAM chips isn’t the easiest thing in the world and you must wondering what prompted this. It seems he wanted to run the LuCI package on the router but it was slow (or even incapable) of booting with the stock hardware’s 16 Mb. He first sourced some pin-compatible replacement chips from an old Pentium III computer. While his soldering iron was hot, he also wired up a JTAG header, which connects via the red wires just visible to the left. When he first fired up the unit he was happy that it was able to boot, but it still only detected 16 Mb.
It turns out you’re going to need to roll your own kernel to get it to take advantage of the upgrade. Source code for OpenWRT is easy to find and there’s plenty of guides for compiling it. If you try this, make sure to read [Heli’s] post carefully as he’s got some important configuration information that will help you to avoid bricking your router.
the folks over at OpenSchemes are at it again. This time they’ve cracked open a low end ZerPlus logic analyzer and modified it to function the same as the higher end model. The 16 channel version they purchased appeared to be fully capable of handling the 32 channels of the more expensive model. The installation of the additional components looks like it might be somewhat difficult, but it is certainly cheap.We love seeing things upgraded for cheap. You might recognize OpenSchemes from when they upgraded the DMM tweezers or hacked the USB serial adapters.