Tag Archives: hardware

RoGeorge Attacks a Pulse Meter

via hardware – Hackaday

The “Crivit Sports” is an inexpensive chest-strap monitor that displays your current pulse rate on a dedicated wristwatch. This would be much more useful, and presumably more expensive, if it had a logging option, or any way to export your pulse data to a more capable device. So [RoGeorge] got to work. Each post of the (so-far) three-part series is worth a read, not the least because of the cool techniques used.

In part one, [RoGeorge] starts out by intercepting the signals. His RF sniffer? An oscilloscope probe shorted out in a loop around the heart monitor. Being able to read the signals, it was time to decode them. Doing pushups and decoding on-off keyed RF signals sounds like the ideal hacker training regimen, but instead [RoGeorge] used a signal generator, clipped to the chest monitor, to generate nice steady “heartbeats” and then read the codes off the scope without breaking a sweat.

With the encoding in hand, and some help from the Internet, he tested out his hypothesis in part two. Using an Arduino to generate the pulses logged in part one, he pulsed a coil and managed to get the heart rates displayed on the watch.

Which brings us to part three. What if there were other secrets to be discovered? Brute-forcing every possible RF signal and looking at the watch to see the result would be useful, but doing so for 8,192 possible codes would drive anyone insane. So [RoGeorge] taught himself OpenCV in Python and pointed a webcam at the watch. He wrote a routine that detected the heart icon blinking, a sign that the watch received a valid code, and then transmitted all possible codes to see which ones were valid. Besides discovering a few redundant codes, he didn’t learn much new from this exercise, but it’s a great technique.

We’re not sure what’s left to do on the Crivit. [RoGeorge] has already figured out the heart-rate data protocol, and could easily make his own logger. We are sure that we liked his thorough and automated approach to testing it all, from signal-generator-as-heartbeat to OpenCV as feedback in a brute-force routine. We can’t wait to see what’s up next.

Filed under: hardware

Using a Decade Counter to Make LEDs Flash

via hardware – Hackaday

[Andrea De Napoli] created a LED display consisting of a half-dozen LEDs connected to the inverted signals of a CD4017 decade counter, giving the effect that a dark LED is running back and forth. The CD4017 works by activating 10 outputs, one at a time, as controlled by a clock signal sent to pin 14.

The first and last LEDs are lit by outputs 0 and 5 with the help of a PNP transistor and a 12K resistor. The middle four LEDs are switched by two outputs each and go dark when one of them goes high. [Andrea] really delves into the CD4017 and he shares a lot of detail in the project page.

Hackaday publishes a lot of posts about obscure ICs: Project 54/74 aims to create a database of die images of 5400 and 7400 series ICs. In a remix of a classic, the Baby 10 uses a 4017 to make a music sequencer.

Filed under: hardware

Completely Owning the Dreamcast Add-on You Never Had

via hardware – Hackaday

If you’ve got a SEGA Dreamcast kicking around in a closet somewhere, and you still have the underutilized add-on Visual Memory Unit (VMU), you’re in for a treat today. If not, but you enjoy incredibly detailed hacks into the depths of slightly aged silicon, you’ll be even more excited. Because [Dmitry Grinberg] has a VMU hack that will awe you with its completeness. With all the bits in place, the hacking tally is a new MAME emulator, an IDA plugin, a never-before ROM dump, and an emulator for an ARM chip that doesn’t exist, running Flappy Bird. All in a month’s work!

The VMU was a Dreamcast add-on that primarily stored game data in its flash memory, but it also had a small LCD display, a D-pad, and inter-VMU communications functions. It also had room for a standalone game which could interact with the main Dreamcast games in limited ways. [Dmitry] wanted to see what else he could do with it. Basically everything.

We can’t do this hack justice in a short write-up, but the outline is that he starts out with the datasheet for the VMU’s CPU, and goes looking for interesting instructions. Then he started reverse engineering the ROM that comes with the SDK, which was only trivially obfuscated. Along the way, he wrote his own IDA plugin for the chip. Discovery of two ROP gadgets allowed him to dump the ROM to flash, where it could be easily read out. Those of you in the VMU community will appreciate the first-ever ROM dump.

On to doing something useful with the device! [Dmitry]’s definition of useful is to have it emulate a modern CPU so that it’s a lot easier to program for. Of course, nobody writes an emulator for modern hardware directly on obsolete hardware — you emulate the obsolete hardware on your laptop to get a debug environment first. So [Dmitry] ported the emulator for the VMU’s CPU that he found in MAME from C++ to C (for reasons that we understand) and customized it for the VMU’s hardware.

Within the emulated VMU, [Dmitry] then wrote the ARM Cortex emulator that it would soon run. But what ARM Cortex to emulate? The Cortex-M0 would have been good enough, but it lacked some instructions that [Dmitry] liked, so he ended up writing an emulator of the not-available-in-silicon Cortex-M23, which had the features he wanted. Load up the Cortex emulator in the VMU, and you can write games for it in C. [Dmitry] provides two demos, naturally: a Mandlebrot set grapher, and Flappy Bird.

Amazed? Yeah, we were as well. But then this is the same guy emulated an ARM chip on the AVR architecture, just to run Linux on an ATMega1284p.

Filed under: handhelds hacks, hardware

Three Thumbs, Way, Way Up!

via hardware – Hackaday

At least one in their lives — or several times a day — everyone has wished they had a third hand to help them with a given task. Adding a mechanical extra arm to one’s outfit is a big step, so it might make sense to smart small, and first add an extra thumb to your hand.

This is not a prosthetic in the traditional sense, but a wearable human augmentation envisioned by [Dani Clode], a master’s student at London’s Royal College of Art. The thumb is 3D-printed out of Ninjaflex and mounted to a printed brace which slides over the hand. One servo rotates the thumb, and a second pulls it closed using a bowden cable system — not unlike that of a bicycle brake. Control of the thumb is achieved by pressure sensors in the wearer’s shoes, linked via Bluetooth to a wristband hosting the servos and the electronics. We already use our hands and feet in conjunction, so why not capitalize on this intuitive link?

The main thrust of this project is to expand human ability and expression: in the same way that a pair of glasses can express individual character while their capacity as a medical device takes a secondary role, [Clode] hopes that her third thumb will have an aesthetic component alongside broadening our capacity as humans. This isn’t to say that traditional prosthetics cannot be works of art in and of themselves.

[Thanks for the tip, Sophi!]

Filed under: hardware, wearable hacks

Hey NASA, Do You Want Your Stuff Back?

via hardware – Hackaday

What would you do if you found hidden away artifacts of aerospace technology from the Apollo era?

You call NASA.

Two hulking computers — likely necessitating the use of a crane to move them — and hundreds of tape reels were discovered in the basement of a former IBM engineer by their heir and a scrap dealer cleaning out the deceased’s home. Labels are scarce, and those that are marked are mostly from the late 1960s through the mid 1970s, including data from the Pioneer 8 to 11 missions, as well as the Helios missions.

Erring on the side of caution, the heir opted to call NASA and attempt to return the tech. The story goes that the late engineer received permission to take the two units and trove of tapes home after they were slated for decommission. Considering their state of disrepair and how dated the technology is, NASA stated they do not do junk removal and recommended their destruction.

One has to guess at what was once on those mysterious tapes — now compromised by mould — but NASA’s archivist’s investigation concluded that there was little data of historical significance stored on them, so fret not.

For a more official trip through NASA’s tech — old and new, check out our tour of their Jet-Propulsion Laboratory, as well as some of their more relatable hacks.

[via Ars Technica]

Filed under: hardware, news

Irising Chicken Coop Door

via hardware – Hackaday

What’s cooler than a door that irises open and closed? Not much. They add a nice science-fictiony detail to any entryway. [Zposner]’s dad wanted an automatic door for his chicken coop, so [zposner] took some time and came up with a nice door for him with an iris mechanism. You’ll need to watch the video.

[Zposner] used a combination of laser cutting and a CNC router to cut the pieces, then sanded and painted the wood. After assembly, [zposner] started work on the control mechanism. He’s controlling the door with an Arduino and a motor shield; to let the Arduino know to stop the motor, [zposner] used limit switches which get hit as the mechanism rotates. Once the switches were in the right place and the code written, it was time to finish assembly and install the door on the coop. To keep the Arduino that safe, it was installed in a plastic container with a screw lid, and then hot-glued to beside the iris.

Unfortunately, chickens don’t necessarily care how cool something is, and in this case, they didn’t realize that the iris was a door – they refused to exit the coop through it. [Zposner] tried a few things before settling on putting the chicken on the edge of the door – then the chicken would realize that it could go through it.

[Zposner]’s dad now has a snazzy door that opens with a switch. It was a great project for [zposner] and his dad to work on and, even if the chickens seem unimpressed, they did a great job. Check out the iris porthole that a Detroit Hackerspace built into its door, or, if you really want to build an iris mechanism, but don’t have access to a CNC router, a laser cutter, or, you know, wood, you could build this out of bits you have lying around.

Filed under: hardware