Tag Archives: uno

This health belt can provide early warning of heart failure

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Heart disease is the most common cause of death — not just in industrialized countries, but for the world as a whole. Many deaths caused by heart failure could be prevented if the patient received medical care sooner, but people are often unaware of impending heart failure until it actually occurs. However, there are physiological indicators that become detectable in advance of heart failure. This wearable “health belt” contains sensors that monitor for those indicators to give warning of imminent heart failure so patients can seek lifesaving medical attention.

This health belt has a variety of sensors to monitor key physiological indicators, including thoracic impedance, heart rate, electrocardiogram activity, and motion activity. None of those alone would reliably correspond to upcoming heart failure without many false positives and negatives, but together they provide a clear picture. The sensor array, which is wearable and resembles a cumberbund, communicates via Bluetooth with the user’s phone. When the signs of heart failure appear, their phone can either notify them to seek medical attention or notify a third party, like a family member or doctor.

The team used an Arduino Uno board to construct their prototype health belt. It connects to several sensors: a peripheral module interface (PMOD) Impedance Analyzer (IA), an AD8232 ECG (electrocardiogram) sensor, a MAX30105 heart rate sensor, and an ADXL362 accelerometer. Power comes from a 9V battery and an HC06 module handles the Bluetooth communication. 

More testing is needed to determine the health belt’s efficacy, as the research team wasn’t able to gather data from people actually experiencing heart failure. But early testing with a subject mimicking similar body movement and breathing was promising.

Image credit: Iqbal, S.M.A., Mahgoub, I., Du, E. et al. Development of a wearable belt with integrated sensors for measuring multiple physiological parameters related to heart failure. Sci Rep 12, 20264 (2022). https://doi.org/10.1038/s41598-022-23680-1

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See how Ben Eater reverse engineered an ’80s TV-censoring device

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Back in the 1980s, there existed a piece of hardware called the “TVGuardian,” which would attempt to censor incoming video in real-time. As recently covered by the wonderful YouTube channel Technology Connections, the TVGuardian reads captioning data as it’s sent and then replaces the bad word(s) with an alternative phrase and also mutes the audio.

Upon learning that the internal dictionary of offensive words is not listed anywhere in the manual, Ben Eater had the idea to extract it himself. After a quick teardown, he discovered a single 93LC86 EEPROM chip functioning in 8-bit mode for a total of 2,048 8-bit words. He then connected an Arduino Uno to the EEPROM’s SPI bus and read 16-byte chunks before dumping the contents to the serial monitor for further investigation.

One of the most interesting findings that Eater discovered was how the words were encoded in blocks of 256 bytes separated by a long string of null characters. Every bad word is an array of bytes for the ASCII characters themselves along with a terminating character and an extra byte at the end, whereas the replacement words are listed as simple character arrays indexed elsewhere. The final byte of each censored word contains flag bits that denote if the word is whitelisted, allowed in non-strict mode, and which G-rated word should replace it. To see this analysis in more detail, check out Eater’s video below!

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Build your own coffee roaster out of a hot air popcorn popper

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Green (unroasted) coffee beans cost about half as much as their roasted counterparts. By purchasing green coffee beans, you can save quite a bit of money in the long term. Roasting your own coffee beans also gives you much greater control over the flavor profile and caffeine content of your coffee (caffeine content is a debatable topic, but light roasts seem to have more caffeine due to overall density). But buying a coffee roasting machine can drain your savings, which is why you might want to follow Eric Sorensen’s lead and build your own coffee roaster.

Roasting coffee beans is not a complex process. In theory, you could roast your wake-up beans in any old oven. But dedicated machines can roast the beans with more consistency to avoid burned or under-roasted individuals. Those machines are very similar to the air poppers used for popping popcorn. They contain a heating element and a motor that spins a fan and agitates the beans. But coffee bean roasting machines add precision temperature control, which increases their price dramatically. By adding your own temperature control to a cheap air popper, you can save a lot of money and still get great results.

This project calls for a few components in addition to the air popper itself (which you can probably get for free at a thrift store). Those parts include an Arduino Uno board, a Nextion touchscreen LCD panel, an L298N motor driver, an Adafruit MCP9600 thermocouple breakout board, and a relay.

The Arduino controls the heating element through the relay with PID control, which means that it modulates power to retain a specified temperature. It monitors the temperature with the thermocouple through the breakout board. The motor driver controls the air popper’s fan, which blows air through the beans and helps to agitate them during roasting. The touchscreen provides an interface to select roasting temperature and time. The firmware written by Sorensen also supports roasting profiles, so you can easily select from preset parameters once you figure out which roasting settings work well. 

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This YouTuber created an Arduino-powered Luxo Jr.

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YouTuber Allyson decided she wanted a real-life version of the Pixar lamp mascot, and actually made one in the video below. Her version uses a servo to raise the modified Luxo lamp up and down via the elbow joint, and another two servos to pan and tilt the shade like a wrist.

The device is controlled by an Arduino Uno, along with a compact vision system. This allows the lamp assembly to move in pre-defined paths and even track objects. The new setup now employs an LED inside of a ping pong ball as the bulb. This can be turned on and off as a “clapper” through a sound sensor.

It looks like a lot of fun so far, and perhaps we’ll see it develop further in the future!

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Building a low-cost flow meter for river studies

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Scientific equipment is notoriously expensive, and for schools, there are often monopolies on which suppliers can provide it. Eben Farnworth wanted to do something about this problem. His design for an open flow meter only costs around $60 USD, which pales in comparison to the typical price tag of $1,000.  

Flow meters are great tools to measure how quickly a liquid (typically water or air) passes through a certain area. By using a propeller inside of an enclosure with a known diameter, the amount of liquid per unit of time can be calculated, along with how fast it is going. Farnworth’s design employs a DN80 water sensor, an Arduino Uno, and a 2.4″ TFT touchscreen.

The case houses all the electronics plus a battery for power. Then at the bottom of the device is a port for plugging in the flow sensor itself. After a bit of calibration, Farnworth was able to get the display to show the flow of a river with impressive accuracy.

To read more about how this flow meter was engineered, check out Farnworth’s project write-up.

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Arduino-controlled gas mixing device fills DIY laser tubes

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Lasers come in two varieties: solid-state and gas tube. As the name suggests, the latter types contain gas. That is a mixture of gas in precise proportions. To fill his DIY laser tube, Cranktown City built an Arduino-controlled gas mixer.

This device has an Arduino Uno board that drives three relay modules. The first relay switches power to a gas pump, the second relay controls an output valve, and the third relay controls an input valve. A push button starts the pumping process. The pump turns on and the input valve opens. Gas from a storage tank is pumped into an inflatable bag. Once the bag is full, as detected by a limit switch, the two valves flip and the gas pumps into the laser tube.

Cranktown City knows the exact volume of the inflatable bag, so he knows how much gas has been pumped into the laser tube each time the device runs. Like mixing a cocktail, this lets him “pour” each part of the gas mixture into the laser tube until he ends up with the correct proportions.

The gas pump, Arduino, relays, and inflatable bag are all enclosed within a heavy duty case made from steel sheet cut on a plasma table. The resulting mixer is portable and robust enough to stand up to abuse of a shop environment. With this device, Cranktown City can continue with developing his DIY laser tube — a project we can’t wait to see completed.

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