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”
The news for RadioShack is not good. The retail chain that we hackers hold near and dear to our hearts is in financial trouble, and could go under next year. With just 64 million in cash on hand, it literally does not have enough capital to close the 1,100 stores it planned to in March of this year.
On May 27th, 2011, we asked you what RadioShack could do to cater to our community. They listened. Most of their retail stores now carry an assortment of Arduino shields, the under appreciated Parallax (why?), and even El Wire. Thanks to you. You made this happen.
Today, we are asking you again. But not for what RadioShack can do better. We’re asking what they can do to survive. To live. It makes no sense for RadioShack to compete in the brutal cell phone/tablet market, and makes every bit of sense for them take advantage of the rapidly growing hacker/builder/maker what-ever-you-want-to-call-us community. Let’s face it. We’re everywhere and our numbers are growing. From 3D printers to drones, the evidence is undeniable.
With 5,000 retail stores across the USA, they are in a perfect position to change their business model to a hacker friendly one. Imagine a RadioShack down the road that stocked PICs, ARMs, Atmels, stepper motors, drivers, sensors, filament….like a Sparkfun retail store. Imagine the ability to just drive a few miles and buy whatever you needed. Would you pay a premium? Would you pay a little extra to have it now? I bet you would.
Now it’s time to speak up. Let your voices be heard. Let’s get the attention of the RadioShack board. You’ve done it before. It’s time to do it again. Hackers unite!
When you’re away from home and your cellphone runs out of juice it can be a real downer. Sure, you could find a store and buy a wall charger, but wouldn’t it be more fun to build your own battery booster without using tools? [Spiritplumber] did just that, popping into a Radio Shack for the parts, then making his how-to video (embedded after the break) while standing at the checkout counter. You can see he hust set his camera on top of the battery display case and got to work.
He’s using four D cell batteries to provide 6 volts of power. Assuming your phone charges at 5 volts this is going to be just a bit too high, even though there’s some tolerance with most phones. To overcome that obstacle he added a diode to the circuit, taking advantage of the 0.7 volt drop that it brings to the mix. Grab a plug adapter for your model and then just hand twist the connections. [Spiritplumber] admits it would be better to solder these, but in a bind you can get away with it. We looked up some prices for this method and we figure this would cost around $18 (batteries included) depending on the price of the plug adapter for your phone.
Of course if you’re just looking for a way to charge your phone without paying consumer prices there are ways of accomplishing that as well.
Continue reading “Cellphone battery booster built at the checkout counter”
It looks like Radio Shack is pretty serious about their new found commitment to their focus on the DIY, inventor, creator and geek demographics. [Ken Gracey], Parallax forum guru, put up a post on the Parallax stuff that will be sold at Radio Shack. Everything is priced, “below spousal approval level,” but no word on what those prices are.
Here’s the (probably not conclusive) list we gleaned from the pics: 2-axis joystick, gyroscope, GPS, compass and altimeter modules, an infrared sensor, 2×16 backlit LCD, BASIC stamp 2 board, and an XBee 2-pack that we assume would be priced above girlfriend approval levels.
We’re curious about how many (and in what quantity) of these items will be stocked at the East Nowheresville strip mall, and again there’s no mention of improving the selection of individual components.
At Hack A Day, we were thinking how amazing a Radio Shack ‘component vending machine’ would be. A modified pick and place machine that will dole out caps, resistors, other components, and has the potential to be competitive with online stores. Anyone feel like sending that suggestion in?
A few months ago, we covered Radio Shack’s efforts to suck less, and the Radio Shack DIY team has now come back with the top ten suggestions submitted. Of course Arduinos make the list at number 1, which we somewhat expected for beginner projects. Here’s the entire list in order:
- More kits and project suggestions
- More introduction/instructional books
- Larger LED selection
- Larger resistor selection
- TONS more capacitors
- DIY audio and speaker equipment
- HAM radio gear
- More competitive pricing
- Stronger sales force
Reader [Mikey Sklar] told us about a review he wrote covering 3 different models of pocket multimeters. We’re sure that you’ve had the same experiences we have being the go-to-guy or got-to-gal for all things electrical. For our sort, having a multimeter on hand at all times has become an expectation.
[Mikey] looks at a model from ebay, Harbor Freight, and Radio Shack. Not surprisingly, the ebay offering doesn’t rate too well but does get the job done. We were surprised to read that he picked up the Cen-Tech model for about $10 at Harbor Freight. Although it may no longer be sold there (we haven’t checked) [Mikey] seems pretty happy with it so we’ll be on the lookout during our next tool-buying trip. We’re unfamiliar with the tiny Radio Shack 22-820 but we’ve always been happy with our larger 22-811. The 22-820 allows the probes to be folded up inside of the case cover for a truly pocketable package.
You can never have too many meters at your disposal and we’ll have to keep this article in mind the next time we’re shopping for another. Never used a multimeter before? Take a look at the tutorial [Mikey] linked to over at ladyada.