Minimizing ESP8266 Battery Drain

[Alex Jensen] wanted to build a battery-powered weather station, using an ESP8266 breakout board to connect to WiFi. However, [Alex]’s research revealed that the ESP chip uses around 70mA per hour when the radio is on — meaning that he’d have to change batteries a lot more than he wanted to. He really wanted a low power rig such that he’d only have to change batteries every 2 years on a pair of AAs.

The two considerations would be, how often does the ESP get powered up for data transmissions — and how often the weather station’s ATtiny85 takes sensor readings. Waking up the ESP from sleep mode takes about 16mA — plus, once awake it takes about 3 seconds to reconnect, precious time at 70mA. However, by using a static IP address he was able to pare that down to half a second, with one more second to do the actual data transmission. In addition to the hourly WiFi connection, the Tiny85 must be powered, though its relatively modest 1.5mA per hour doesn’t amount to much, even with the chip awake for 36 hours during the year. All told, the various components came to around 500 mAh per year, so using a pair of AA batteries should keep the rig going for years.

We’re intrigued by stories of hackers eking out every last drop of power to make their projects work. We’ve posted about ESPs low-power mode before, and what can be more low-power than a watch running off a coin cell?

Will Your Next Whip Pack Memory Chainmail Tires?

NASA’s Glenn Research Center is experimenting with nickel-titanium memory alloy tires that resemble chain mail. It’s an intriguing angle — the tires can withstand heavier loads and at higher speeds. They’re airless and immune to puncture. Presumably they’re not literally chainmail but closer to a sweater in construction.

This tire is a culmination of a number of fascinating research drives. NASA has been experimenting with tensegrity structures as a means of building in space without spending a ton of rocket fuel on heavy hardware. These structures use tensioned cables to maintain a three-dimensional structure. The tires use the stiffness of the wire as well as internal stiffeners to maintain shape, without the need for a whole rim.

In addition to structural tensegrity, the memory alloy also helps keep its original shape by resisting deformation — it springs back into its original shape. When ordinary materials are stretched, you’re stretching the bonds between the atomic structures. NASA’s NiTi alloy goes through an “atomic rearrangement” when stressed, easing the forces put on those structures. As a result, the alloy can withstand 10% deformation versus 0.3% for spring steels, or about 30 times the deformation that a normal alloy could withstand without having permanent deformation occur — dents, basically. NASA’s tires can actually compress down to the axle and then pop back.

Continue reading “Will Your Next Whip Pack Memory Chainmail Tires?”

Classic Furby plus Alexa Equals… Furlexa

[Zach Levine] wrote in to share a project just completed: a classic Furby packing a Raspberry Pi running Alexa: he calls it Furlexa.

The original Furby product wowed consumers of the 90s. In addition to animatronic movements, it also packed simulated voice learning technology that seemed to allow the Furby to learn to speak. It wasn’t like anything else on the market, and even got the toy banned from NSA’s facilities in case it could spy on them. Elegantly, the robot uses only one motor to move all of its parts, using a variety of plastic gears, levers, and cams to control all of the robot’s body parts and to make it dance.

Over the past twenty years the Furby has earned the reputation as one of the most hackable toys ever — despite its mystery microcontroller, which was sealed in plastic to keep the manufacturer’s IP secret. [Zach] replaced the control board with a Pi Zero. He also replaced the crappy mic and pizeo speaker that came with toy with a Pimoroni Speaker pHat and a better mic.

While classic Furbys have a reputation for hackability, the new ones aren’t immune: this Infiltrating Furby is based on a recent model of the toy. Continue reading “Classic Furby plus Alexa Equals… Furlexa”

Zigbee-Based Wireless Arduinos, Demystified

Hackday regular [Akiba] is working on a series of video tutorials guiding newbies into the world of the 802.15.4 wireless protocol stack — also known as ZigBee. So far, his tutorials include a “getting started with chibiArduino”, his own Arduino-based wireless library, as well as a more basic tutorial on how radio works.

[Akiba] already made a name for himself though a large number of wireless projects, including his Saboten sensor boards, which are ruggedized for long-term environmental monitoring. The Saboten boards use the same wireless stack as his Arduino-compatible wireless development boards, his Freakduino products. The latest version features an ATmega 1284P with 8x the RAM and 4x the flash of the older, 328P-based Freakduinos. It comes in both 900 MHz and 2.4 GHz and there’s also a special 900 Mhz “Long Range” variant. The boards include some great power-saving features, including switchable status LEDs and on-board battery regulation circuity allowing one to run a full year on two AA cells while in sleep mode. They also have a USB stick configuration that is great for Raspberry Pi projects and for running straight from the PC.

For more [Akiba] goodness, check out our colleague [Sophi]’s SuperCon interview with him as well as our coverage of his Puerto Rico lantern project.

Intellibuoy Keeps Track of the Water

With world oceans ranging in cleanliness from pretty nasty to OMG, we need to get a handle on what exactly is going on. High School students from Hackensack, NJ built the Intellibuoy, a floating water quality sensor. The buoy has an anemometer and digital rain gauge up top, as well as a LED beacon to comply with maritime regulations.

Flotation is provided by a framework of sealed 3/4″ and 3″ PVC pipes that look strong enough to protect the electronics from a casual boat-bump. High above the water (under ideal conditions) there is the waterproof control box, packing two Arduino UNOs which listen to the sensors. A turbidity sensor measures how much silt is in the water; the other sensors measure Ph, dissolved oxygen, and temperature. The sensor pod is suspended inside a double ring of PVC for maximum protection. Each ‘Duino also has a SD card shield that stores the data of the respective sensors.

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Stepper Driver Module with Swappable Heatsinks

At first glance, [Dean Gouramanis]’s stepper driver module for 3D printers looks like just another RAMPS-compatible stepper board. Except, what could that gold-plated copper peg sticking out of the PCB possibly be? That would be [Dean]’s PowerPeg Thermal Management System that he built and entered in the Hackaday Prize competition for 2015, where it rocked its way into the Finals. It’s a thermal connector peg that attaches to a variety of heatsinks so you can swap in whatever sink fits the bill.

In the case of this project, [Dean] created a custom PCB that accommodates the PowerPeg connector, onto which the heat sink screws. Needless to say, he machined his own heatsinks to go with the pegs, though it looks like you could use any sink with enough surface contact that can be secured by the same #0-80 screw.

You shouldn’t be surprised that hackers obsess over heatsinks. This heatsink tester project we published helps determine which sink  to use. Another post gives all the ins and outs of ordering a custom heatsink.

Glue Gun Teardown Reveals Microcontroller Mystery

[electrobob] got a Bosch GluePen cordless hot glue gun. The thing has some nice features — it heats up in fifteen seconds, and charges via USB, and is generally handy for those small and quick jobs that hot glue guns were made to perform. At first glance it seems like a huge improvement over the plug-in varieties, which seem to take forever to heat up when all you need is a quick dab of glue.

As cool as the product sounded, [bob] did what any right-minded hacker would do and opened it up to see how that sucker work and found an ATtiny24A inside. What’s most interesting is that there appears to be no temperature regulation or sensing capability, with the exception of the thermistor in the battery-charging circuit. It’s an intriguing mystery.

The ATtiny controls a power MOSFET that brings the heating element to “approximately 170 degrees” according to the manual. [bob] could find no temperature regulation of the hot end, which measures a steady 12 V at the gate of the transistor then entire time the glue gun is powered on.

That ATtiny24A that runs the whole thing packs 12 GPIO pins, 4 PWM channels, and 2 KB program memory. It appears a bit overpowered for a glue gun controller. [bob] found one of the Tiny’s pins connected the heating element and another to the charging circuit. Maybe a shutoff in case the battery catches fire?

Without a clear shot of the back of the board, it’s a bit of a guessing game, but eight of the twelve GPIO pins appear to be in use. Leave your theories in comments. And if you’ve got any bright ideas about what to do with the remaining four GPIO pins, have at it!

For another of [bob]’s tool hacks, check out his constant current sink we posted earlier this year.