PVC Pipe Turned Portable Bluetooth Speaker

October 7, 2019 by Tom Nardi 7 Comments

We’ve always felt that sections of PVC pipe from the home improvement store are a criminally underutilized construction material, and it looks like [Troy Proffitt] feels the same way. Rather than trying to entirely 3D print the enclosure for his recently completed portable Bluetooth speaker, he combined printed parts with a piece of four inch pipe from the Home Depot.

While using PVC pipe naturally means your final hardware will have a distinctly cylindrical look, it does provide compelling advantages over trying to print the entire thing. For one, printing an enclosure this large would have taken hours or potentially even days. But by limiting the printed parts to accessories like the face plate, handle, and caps, [Troy] reduced that time considerably. Of course, even if you’re not in a rush, it’s worth mentioning that a PVC pipe will be far stronger than anything your desktop FDM printer is likely to squirt out.

[Troy] provides links for all the hardware he used, such as the speakers, tweeters, and the Bluetooth audio board itself. The system is powered by an 1800 mAh 3S RC-style battery pack that he says lasts for hours, though he also links to a wall adapter that can be used if you don’t mind being tethered. Unfortunately it doesn’t look like he has any internal shots of the build, but given the relatively short parts list, we imagine it’s all fairly straightforward inside.

While this is certainly a respectable looking build considering it started life in the plumbing aisle, we have to admit that we’ve seen some portable Bluetooth speakers with fully 3D printed enclosures in the past that looked absolutely phenomenal. The tradeoff seems pretty clear: reuse existing materials to save time, print them if you don’t mind reinventing the wheel occasionally.

Smartphone Case Doubles As Chording Keyboard, With Gesture Inputs

September 25, 2019 by Donald Papp 6 Comments

Smartphones and other modern computing devices are wonderful things, but for those with disabilities interacting with them isn’t always easy. In trying to improve accessibility, [Dougie Mann] created TypeCase, a combination gestural input device and chording keyboard that exists in a kind of symbiotic relationship with a user’s smartphone.

With TypeCase, a user can control a computer (or the smartphone itself) with gestures, emulate a mouse, or use the device as a one-handed chording keyboard for text input. The latter provides an alternative to voice input, which can be awkward in public areas.

The buttons and motion sensors allow for one-handed button and gestural input while holding the phone, and the Bluetooth connectivity means that the device acts and works just like a wireless mouse or keyboard. The electronics consist mainly of an Adafruit Feather 32u4 Bluefruit LE, and [Dougie] used 3D Hub’s on-demand printing service to create the enclosures once the design work was complete. Since TypeCase doubles as a protective smartphone case, users have no need to carry or manage a separate device.

TypeCase’s use cases are probably best expressed by [Dougie]’s demo video, embedded below. Chording keyboards have a higher learning curve, but they can be very compact. One-handed text input does remind us somewhat of a very different approach that had the user make gestures in patterns reminiscent of Palm’s old Graffiti system; perhaps easier to learn but not nearly as discreet.

Continue reading “Smartphone Case Doubles As Chording Keyboard, With Gesture Inputs” →

ESPcopter: A Fully Customizable Drone

September 25, 2019 by Sharon Lin 5 Comments

With so many capabilities for obstacle avoidance, the only natural progression for drones would be for them to be hand-controlled. For Turkish inventor [metehanemlik], even this wasn’t enough of a challenge, as he decided to create the ESP8266-Powered Mini Drone: ESPcopter, a programmable Arduino-compatible modular drone that is open to modding through expansion shields. Not only can DIY enthusiasts modify the algorithms used for obstacle avoidance, but the drone can be sized to whatever dimensions fit their needs.

The drone is almost entirely built from expansion shields, including the multi-ranger shield with four VL53L0x laser-ranging sensors on the forward, backward, right, and left directions of the drone. The website for the ESPcopter comes with an SDK that lets users easily modify the software running on the drone’s MCU as well as pinouts to better understand its hardware functionality. Impressively, it was fully funded through a 60-day crowdfunding campaign, and will be undergoing a second launch shortly, with some new and improved features.

Power comes from a 26 0mAh LiPo battery that allows for up to six minutes of flight time; includes a 3-axis gyroscope, accelerometer, and magnetometer; runs on an ESP8266-12S 32-bit MCU; fully charges within 45 minutes through a USB connection; weighs around 35 g; and is about 90 mm from motor to motor. Continue reading “ESPcopter: A Fully Customizable Drone” →

Fighting Household Air Pollution

September 24, 2019 by Sharon Lin 35 Comments

When Kenyan engineer [Aloise] found out about the health risks of household air pollution, they knew there had to be a smart solution to combatting the problem while still providing a reasonable source of energy for families cooking without the luxury of cleaner fuels. Enter OpenHAP, a DIY household air pollution monitor that provides citizen scientists and researches the means to measure air particulates in developing countries.

The device is based on an ESP32 communicating with a ZH03B Particulate matter sensor over UART; a DS3231SN real-time clock (RTC), temperature and humidity sensor, and MLX90640 2D thermal sensor array over I2C; and wirelessly sending the data received to a Bluetooth low energy wrist-strap beacon and an Internet enabled phone. The device also uses a TCA9534 GPIO expander to control the visual and auditory notifiers (buzzers and LEDs) and to interface to a SD card.

The project uses the libesphttpd project modified for the ESP32 for the webserver, which is used to stream data to a mobile handset or computer using the WiFi capabilities of the ESP32. The data includes real-time sensor information, system status, storage media status, visualizations of the thermal array sensor data (to ensure the camera is facing the source of heat), and tag information to test the limits of the Bluetooth tag with regards to distance.

Power input is provided through a Micro-USB connector, protected with a TVS diode and a Schottky diode in series to prevent reverse power flow.

The project was tested in two real-life scenarios: one with a household in rural Kenya and another with an urban low-income family of four. In the first test, the family used a three stone open fire stove. A FLiR thermal camera captured the stove temperatures, while a standard camera was enough to capture the high levels of smoke inside the kitchen. The readings from OpenHAP were high enough to exceed the upper detection threshold for the particulate sensor, showing that the woman cooking in the house was receiving the equivalent of 8 cigarettes a day, about 8 x the WHO’s recommended particulate levels.

Within the second household, a typical energy mix of charcoal briquettes and kerosene was typically used for cooking, with kerosene used during the day and briquettes used at night. The results from measuring pollution levels using OpenHAP showed that the mother and child in the household regularly received around 1.5 x the recommended limit of pollutants, enough to lead to slow suffocation.

There’s already immense potential for this project to help researchers test out different energy sources for rural households, not to mention the advantage of having a portable low-energy pollution monitor for citizen scientists.

Continue reading “Fighting Household Air Pollution” →

LoRa-Based Plant Monitoring

September 23, 2019 by Sharon Lin 28 Comments

Croatian engineers [Slaven Damjanovic] and [Marko Čalić] have developed a wireless system for farmers to monitor plant conditions and weather along their agricultural fields. The system uses an RFM95W module for LoRa communication, and devices are designed to be plug-and-play, battery-powered, and have long-range communication (up to 10km from the gateway).

It uses an ATMega328 microprocessor, and includes sensors for measuring soil moisture (FC28 sensor), leaf moisture (FC37 sensor), pressure (BME280 sensor), and air temperature and humidity (DHT22 or SHT71 sensor). The data is sent to a multichannel The Things Network gateway that forwards the information to an external database, which then displays the data through a series of graphs and tables.

The software for sending messages to the gateway is based on the LoRa MAC in C (LMIC) and LowPower libraries and was developed by [ph2lb].

Continue reading “LoRa-Based Plant Monitoring” →

Dissecting The TL-WR841N For Fun And Profit

September 12, 2019 by Tom Nardi 34 Comments

The TP-Link TL-WR841N isn’t a particularly impressive piece of hardware, but since it works decently well and sells for under $20 USD, it’s one of the most popular consumer routers on Amazon. Now, thanks to [TrendyTofu] of the Zero Day Initiative, we now have a concise step-by-step guide on how to hack your way into the newer versions of the hardware and take full control over this bargain WiFi device. This work was initially done to help test out reported vulnerabilities in the router’s firmware, but we’re sure the readers of Hackaday can come up with all sorts of potential uses for this information.

The story starts, as so many before it have, with a serial port. Finding the UART pads on the PCB and wiring up a level shifter was no problem, but [TrendyTofu] found it was only working one-way. Some troubleshooting and an oscilloscope later, the culprit was found to be a 1kΩ pull down resistor connected to the RX line that was keeping the voltage from peaking high enough to be recognized.

Once two-way communication was established, proper poking around inside the router’s Linux operating system could begin. It wasn’t a huge surprise to find the kernel was ancient (version 2.6.36, from 2010) and that the system utilities had been stripped to the absolute bare minimum to save space. Replacing the firmware entirely would of course be ideal, but unfortunately OpenWRT has dropped support for the newer hardware revisions of the TL-WR841N.

To teach this barebones build of Linux some new tricks, [TrendyTofu] used the mount command to find a partition on the system that actually had write-access, and used that to stash a pre-compiled build of BusyBox for MIPS. With a more complete set of tools, the real fun could begin: using GDB to debug TP-Link’s binaries and look for chinks in the armor. But feel free to insert your own brand of mayhem here.

You might think that in the era of the Raspberry Pi, abusing cheap routers to turn them into general purpose Linux boxes would be somewhat out of style. Frankly, you’d be right. But while the days of strapping Linksys WRT54Gs to remote controlled cars might be long be gone, there are still some routers out there interesting enough to make it worth dusting off this time-honored hardware hacker tradition.

Handheld LoRa Joystick For Long-Range Bots

September 11, 2019 by Tom Nardi 11 Comments

Wanting a simple tool to aid in the development of LoRa controlled robotic projects, [Jay Doscher] put together this very slick one-handed controller based on the 900 MHz Adafruit Feather M0. With a single trigger and a miniature analog joystick it’s a fairly simple input device, but should be just enough to test basic functionality of whatever moving gadget you might find yourself working on.

Wiring for this project is about as simple as you’d expect, with the trigger and joystick hanging off the Feather’s digital ports. The CircuitPython code is also very straightforward, though [Jay] says in the future he might expand on this a bit to support LoRaWAN. The controller was designed as a barebones diagnostic tool, but the hardware and software in its current form offers an excellent opportunity to layer additional functionality on a known good base.

Everything is held inside a very well designed 3D printed enclosure which [Jay] ran off on his ELEGOO Mars, one of the new breed of low-cost resin 3D printers. The machine might be pretty cheap, but the results speak for themselves. While resin printing certainly has its downsides, it’s hard not to be impressed by the finish quality of this enclosure.

While LoRa is generally used for transmitting small bits of information over long distances, such as from remote sensors, this isn’t the first time we’ve seen it used for direct control of a moving object. If you’re not up to speed on LoRa, check out this excellent talk from [Reinier van der Lee] that goes over the basics of the technology and how he used it to build a community sensor network.