A Freeze Dryer You Can Build In Your Garage

February 7, 2018 by Brian McEvoy 41 Comments

What do trail mix, astronaut ice-cream, and cryogel have in common? This may sound like the introduction to a corny riddle, but they are all things you can make in your garage with a homemade freeze dryer. [The Thought Emporium] built his own freeze dryer with minimum fuss and only a few exotic components like a vacuum pump and a high-quality pressure gauge. The video is also posted after the break which contains a list for the parts and where they can be purchased.

Freeze drying uses a process called cryodesiccation or lyophilization. Below a certain pressure, water skips the liquid phase and goes directly to a gas, so frozen items can transition from ice to dry without a soggy step. When you jump the liquid phase, objects hold their shape when they were frozen, and since no heat is used, you don’t carmelize your sugars.

A freeze-dryer like this has three parts. The first is the pump which doesn’t need any explanation. Next to the pump there must be a water trap. This chilly compartment recondenses the water vapor, so it doesn’t get inside the pump or saturate the things you’re trying to dry. Lastly, there is the drying chamber where your items are placed to have their moisture taken out.

Astronaut ice cream has been made on Hackaday before. [The Thought Emporium] has also been seen including a piece on making your own graphene.

Continue reading “A Freeze Dryer You Can Build In Your Garage” →

Indexing Chuck Not Required

January 25, 2018 by Brian McEvoy 15 Comments

Becoming accomplished with a lathe is a powerful skillset, but it’s only half of the journey. Being clever comes later, and it’s the second part of the course. Patience is in there somewhere too, but let’s focus on being clever. [TimNummy] wants a knobbed bolt with critical parameters, so he makes his own. After the break, there is a sixty-second summary of the linked video.

Making stock hardware is a beginner’s tasks, so custom hardware requires ingenuity or expensive machinery. Adding finger notches to a bolthead is arbitrary with an indexing chuck, but one isn’t available. Instead, hex stock becomes a jig, and the flat sides are utilized to hold the workpiece at six intermittent angles. We can’t argue with the results which look like a part that would cost a pretty penny.

Using material found in the workshop is what being clever is all about. Hex brass stock comes with tight tolerances on the sides and angles so why not take advantage of that?

[TimNummy] can be seen on HaD for his Jeep dome light hack and an over-engineered mailbox flag. Did you miss [Quinn Dunki]’s piece on bootstrapping precision machine tools? Go check that out!

Continue reading “Indexing Chuck Not Required” →

Long-Range RFID Leaflets

January 19, 2018 by Brian McEvoy 29 Comments

Pick a card, any card. [Andrew Quitmeyer] and [Madeline Schwartzman] make sure that any card you pick will match their NYC art installation. “Replantment” is an interactive art installation which invites guests to view full-size leaf ~~molds~~ casts from around the world.

A receipt file with leaf images is kept out of range in this art installation. When a viewer selects one, and carries it to the viewing area, an RFID reader tells an Arduino which tag has been detected. Solid-state relays control two recycled clothing conveyors draped with clear curtains. The simple units used to be back-and-forth control but through dead-reckoning, they can present any leaf ~~mold~~ cast front-and-center.

Clothing conveyors from the last century weren’t this smart before, and it begs the question about inventory automation in small businesses or businesses with limited space.

We haven’t seen much long-range RFID, probably because of cost. Ordinary tags have been read at a distance with this portable reader though, and NFC has been transmitted across a room, sort of.

Continue reading “Long-Range RFID Leaflets” →

Digital Mouse Trap

January 11, 2018 by Brian McEvoy 12 Comments

Plenty of PC games rely on the mouse for input, and browser games are no exception. Unfortunately though, this isn’t always the most intuitive controller. [Nathan Ramanathan] combined a couple hacks to get the controller he wanted for playing browser games like Agar and Slither. No rodents were harmed in this project.

The games he wanted to dominate were top-down view so there was no need to move the mouse far from the center of the screen. For a more intuitive interface, a Wii nunchuck with its integrated joystick was selected. Nunchucks were notoriously hackable. An Arduino converted the nunchuck’s data into mouse movements. Inside the computer, Autohotkey kept the mouse pointer reined in where it was useful. Autohotkey was a scripting tool for executing keyboard and mouse macros.

The result was a joystick which controlled these browser games exactly the way you would expect a joystick to control a game. Mouse functionality, including standard and fast scrolling, was an added bonus so games like Minecraft aren’t left behind. The ergonomics of the nunchuck make us wonder why it hasn’t been seen in more wearable hacks.

Custom game controllers are no stranger to Hackaday readers. We’ve seen them built from LEGO blocks, automobiles, and even a decorative rug.

Continue reading “Digital Mouse Trap” →

34C3: Fitbit Sniffing And Firmware Hacking

December 29, 2017 by Brian McEvoy 19 Comments

If you walked into a gym and asked to sniff exercise equipment you would get some mighty strange looks. If you tell hackers you’ve sniffed a Fitbit, you might be asked to give a presentation. [Jiska] and [DanielAW] were not only able to sniff Bluetooth data from a run-of-the-mill Fitbit fitness tracker, they were also able to connect to the hardware with data lines using test points etched right on the board. Their Fitbit sniffing talk at 34C3 can be seen after the break. We appreciate their warning that opening a Fitbit will undoubtedly void your warranty since Fitbits don’t fare so well after the sealed case is cracked. It’s all in the name of science.

There’s some interesting background on how Fitbit generally work. For instance, the Fitbit pairs with your phone which needs to be validated with the cloud server. But once the cloud server sends back authentication credentials they will never change because they’re bound to to the device ID of the Fitbit. This process is vulnerable to replay attacks.

Data begin sent between the Fitbit and the phone can be encrypted, but there is a live mode that sends the data as plain text. The implementation seemed to be security by obscurity as a new Bluetooth handle is used for this mode. This technique prevents the need to send every encrypted packet to the server for decryption (which would be for every heartbeat packet). So far the fix for this has been the ability to disable live mode. If you have your own Fitbit to play with, sniffing live mode would be a fun place to start.

The hardware side of this hack begins by completely removing the PCB from the rubber case. The board is running an STM32 and the team wanted to get deep access by enabling GDB. Unfortunately, the debug pins were only enabled during reset and the stock firmware disables them at startup (as it should). The workaround was to rewrite the firmware so that the necessary GPIO remain active and there’s an interesting approach here. You may remember [Daniel Wegemer] from the Nexmon project that reverse engineered the Nexus 5 WiFi. He leveraged the binary patching he used on Nexmon to patch the Fitbit firmware to enable debugging support. Sneaky!

For more about 34C3 we have a cheatsheet of the first day and for more about Fitbit security, check out this WAV file.

Continue reading “34C3: Fitbit Sniffing And Firmware Hacking” →

Vacuum Molding With Kitchen Materials

December 26, 2017 by Brian McEvoy 14 Comments

Vacuum pumps are powerful tools because the atmospheric pressure on our planet’s surface is strong. That pressure is enough to crush evacuated vessels with impressive implosive force. At less extreme pressure differences, [hopsenrobsen] shows us how to cleverly use kitchen materials for vacuum molding fiberglass parts in a video can be seen after the break. The same technique will also work for carbon fiber molding.

We’ve seen these techniques used with commercially available vacuum bags and a wet/dry vac but in the video, we see how to make an ordinary trash bag into a container capable of forming a professional looking longboard battery cover. If the garbage bag isn’t enough of a hack, a ball of steel wool is used to keep the bag from interfering with the air hose. Some of us keep these common kitchen materials in the same cabinet so gathering them should ’t be a problem.

Epoxy should be mixed according to the directions and even though it wasn’t shown in the video, some epoxies necessitate a respirator. If you’re not sure, wear one. Lungs are important.

Fiberglass parts are not just functional, they can be beautiful. If plastic is your jam, vacuums form those parts as well. If you came simply for vacuums, how about MATLAB on a Roomba?

Thank you [Jim] who gave us this tip in the comments section about an electric longboard.

Continue reading “Vacuum Molding With Kitchen Materials” →

Welding Batteries With Batteries

December 19, 2017 by Brian McEvoy 8 Comments

Welding equipment is always expensive and bulky, right? Heavens no! [Jaromir Sukuba] is making a welder for battery tabs which can fit in a pocket and gets its power from a coin cell. It may be expensive to power compared to a mains welder, but for the sake of portability this is quite the hack. Not only that, but it uses 555 timers in the charging circuit.

His entry for the 2017 Coin Cell Challenge saps every bit of power from a coin cell and stores it up in a 100F supercapacitor bank. All that stored energy takes a long time to get into the supercapacitors but it comes out in a flash. In fact, it can take 12 hours to fully charge. For the convenience of size, we have to trade the convenience of speed. This should be a strong contestant for the Supernova and Heavy Lifting categories.

We see a quick demonstration of a successfully welded tab which shows that using coin cells to weld metal to coin cells is equally ironic and apropos. Other welders on Hackaday feature a quicker way to control your battery tab welding, safety-rich spot welding, or just go off the rails completely and use an arc welder to make a coil gun.