How Does Time Work On The Moon?

We’re looking to go back to the Moon. Not just with robots this time, but with astronauts, too! They’ll be doing all kinds of interesting things when they get there. Maybe they’ll even work towards establishing a more permanent presence for humanity on the lunar surface, in which case they’ll have to get up in the morning, eat breakfast, and get to work.

This raises the question—how does time work on the Moon? As simple as they can be down here, Earthly days and years have little meaning up there, after all. So what’s going on up there?

Continue reading “How Does Time Work On The Moon?”

Reprogrammable Transistors

Not every computer can make use of a disk drive when it needs to store persistent data. Embedded systems especially have pushed the development of a series of erasable programmable read-only memories (EPROMs) because of their need for speed and reliability. But erasing memory and writing it over again, whether it’s an EPROM, an EEPROM, an FPGA, or some other type of configurable solid-state memory is just scratching the surface of what it might be possible to get integrated circuits and their transistors to do. This team has created a transistor that itself is programmable.

Rather than doping the semiconductor material with impurities to create the electrical characteristics needed for the transistor, the team from TU Wien in Vienna has developed a way to “electrostatically dope” the semiconductor, using electric fields instead of physical impurities to achieve the performance needed in the material. A second gate, called the program gate, can be used to reconfigure the electric fields within the transistor, changing its properties on the fly. This still requires some electrical control, though, so the team doesn’t expect their new invention to outright replace all transistors in the future, and they also note that it’s unlikely that these could be made as small as existing transistors due to the extra complexity.

While the article from IEEE lists some potential applications for this technology in the broad sense, we’d like to see what these transistors are actually capable of doing on a more specific level. It seems like these types of circuits could improve efficiency, as fewer transistors might be needed for a wider variety of tasks, and that there are certainly some enhanced security features these could provide as well. For a refresher on the operation of an everyday transistor, though, take a look at this guide to the field-effect transistor.

This Air Particulate Sensor Can Also Check Your Pulse Rate

The MAX30105 is an optical sensor capable of a great many things. It can sense particulate matter in the air, or pick up the blinking of an eye. Or, you can use it as a rudimentary way to measure your heart rate and blood oxygen levels. It’s by no means a medical grade tool, but this build from [Taste The Code] is still quite impressive.

The MAX30105 contains red, green, and infrared LEDs, and a very sensitive light detector. The way it works is by turning on its different LEDs, and then carefully measuring what gets reflected back. In this way it can measure particles in the air,  such as smoke, which is actually what it was designed for originally. Or, if you press your finger up against it, it can measure the light coming back from your blood and determine its oxygenation level. By detecting the variation in the light over time, it’s possible to pick up your pulse, too.

Getting this data out of the sensor is remarkably easy. One need only hook it up to a suitable microcontroller like the ESP8266 and use the MAX3010X library to talk to it. [Taste The Code] did exactly that, and also hooked up a screen for displaying the captured data. Alternatively, if you want the raw data from the sensor, you can get that too.

It should be noted that this build was done for educational purposes only. You shouldn’t rely on a simple DIY device for gathering useful medical data; there are reasons the real gear is so expensive, after all. We’ve looked at this sensor before, too, not long after it first hit the market. Continue reading “This Air Particulate Sensor Can Also Check Your Pulse Rate”