A Wireless Webcam Without A Cumbersome Cloud Service

After a friend bought a nannycam that required the use of a cloud service to make the device useful,  [Martin Caarels] thought to himself — as he puts it — ”I can probably do this with a Raspberry Pi!

Altogether, [Caarels] gathered together a 4000mAh battery, a Raspberry Pi 3 with a micro SD card for storage, a Logitech c270 webcam, and the critical component to bind this project together: an elastic band. Once he had downloaded and set up Raspbian Stretch Lite on the SD card, he popped it into the Pi and connected it to the network via a cable. From there, he had to ssh into the Pi to get its IP so he could have it hop onto the WiFi.

Now that he effectively had a wireless webcam, it was time to turn it into a proper security camera.

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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.

Dumb Box? Make it Really Smart!

[Stephen Harrison]’s Really Smart Box is a great concept, it’s simultaneously a simple idea while at the same time being super clever. The Really Smart Box isn’t really a box; it’s a drop-in platform that can be made any size, intended to turn any dumb storage box into one that helps manage and track levels and usage of any sort of stock or consumable.

It does this by measuring the weight of the stuff piled on top of it, while also monitoring temperature and humidity. The platform communicates this information wirelessly to a back end, allowing decisions to be made about stock levels, usage, and monitoring of storage conditions. It’s clearly best applied to consumables or other stock that comes and goes. The Really Smart Box platform is battery-powered, but spends most of its time asleep to maximize battery life. The prototype uses the SigFox IoT framework for the wireless data, which we have seen before in a wireless swimming pool monitor.

This is still just a prototype and there are bugs to iron out, but it works and [Stephen] intends to set-and-forget the prototype into the Cambridge Makespace with the task of storing and monitoring 3D printer filament. A brief demo video is embedded below.

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Fridge Alarm Speaks, and Saves Power & Food

One of the most power-hungry devices in our homes, besides the air conditioner or heater, is our refrigerator and freezer. It’s especially so if the door doesn’t close all the way or the magnetic seal doesn’t seat properly. [Javier] took to solving a recurring problem with his personal fridge by attaching an alarm to the door to make sure that it doesn’t consume any more power than it absolutely needs.

At its core the device is straightforward. A micro switch powers a small microcontroller only when the door is open. If the door is open for too long, the microcontroller swings into action. The device then powers up a small wireless card (which looks like a variant of the very well-documented ESP module), that communicates with his microwave of all things, which in turn alerts him with an audible, spoken alarm that the refrigerator hasn’t closed all the way. It’s all powered with a battery that will eventually need to be recharged.

While there are certainly easier ways to implement an alarm, the use of the spoken alarm is a nice touch for this project, and the power savings that can be realized are not insignificant. There’s also the added benefit that [Javier] can prevent his freezer from frosting over. If you’re in the mood for other great fridge hacks, there are other exciting, novel, and surely one-of-a-kind ways to trick out your refrigerator.

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Wireless Oscilloscope Review

[Martin Rowe] over at EDN recently put a $200 wireless oscilloscope to the test. The Aeroscope 100A is a single channel scope in a probe body that communicates back to an Apple smartphone or tablet via Bluetooth LE. You can see the video from the post, below.

The original prototype of the device had a high bandwidth, but the production model only manages to have a 20 MHz bandwidth at 100 megasamples per second: nothing earth-shattering.

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Piezomagnetic Trick Shrinks 2.5 GHz Antennas

To a ham radio operator used to “short”-wave antennas with lengths listed in tens of meters, the tiny antennas used in the gigahertz bands barely even register. But if your goal is making radio electronics that’s small enough to swallow, an antenna of a few centimeters is too big. Physics determines plausible antenna sizes, and there’s no way around that, but a large group of researchers and engineers have found a way of side-stepping the problem: resonating a nano-antenna acoustically instead of electromagnetically.

Normal antennas are tuned to some extent to the frequency that you want to pick up. Since the wavelength of a 2.5 GHz electromagnetic wave in free space is 120 cm mm, most practical antennas need a wire in the 12-60 cm mm range to bounce signals back and forth. The trick in the paper is to use a special piezomagnetic material as the antenna. Incoming radio waves get quickly turned into acoustic waves — physical movement in the nano-crystals. Since these sound waves travel a lot slower than the speed of light, they resonate off the walls of the crystal over a much shorter distance. A piezoelectric film layer turns these vibrations back into electrical signals.

Ceramic chip antennas use a similar trick. There, electromagnetic waves are slowed down inside the high-permittivity ceramic. But chip antennas are just slowing down EM waves, whereas the research demonstrated here is converting the EM to sound waves, which travel many orders of magnitude slower. Nice trick.

Granted, significant material science derring-do makes this possible, and you’re not going to be fabricating your own nanoscale piezomagnetic antennas any time soon, but with everything but the antenna getting nano-ified, it’s exciting to think of a future where the antennas can be baked directly into the IC.

Thanks [Ostracus] for the tip in the comments of this post on antenna basics. Via [Science Magazine].

The Things Network Sets 702 km Distance Record For LoRaWAN

Many of us will have at some time over the last couple of years bought a LoRaWAN module or two to evaluate the low power freely accessible wireless networking technology. Some have produced exciting and innovative projects using them while maybe the rest of us still have them on our benches as reminders of projects half-completed.

If your LoRaWAN deployment made it on-air, you’ll be familiar with the range that can be expected. A mile or two with little omnidirectional antennas if you are lucky. A few more miles if you reach for something with a bit of directionality. Add some elevation, and range increases.

A couple of weeks ago at an alternative society festival in the Netherlands, a balloon was launched with a LoRaWAN payload on board that was later found to have made what is believed to be a new distance record for successful reception of a LoRaWAN packet. While the balloon was at an altitude of 38.772 km (about 127204.7 feet) somewhere close to the border between Germany and the Netherlands, it was spotted by a The Things Network node in Wroclaw, Poland, at a distance of 702.676km, or about 436 miles. The Things Network is an open source, community driven effort that has built a worldwide LoRaWAN network.

Of course, a free-space distance record for a balloon near the edge of space might sound very cool and all that, but it’s not going to be of much relevance when you are wrestling with the challenge of getting sensor data through suburbia. But it does provide an interesting demonstration of the capabilities of LoRaWAN over some other similar technologies, if a 25mW (14dBm) transmitter can successfully send a packet over that distance then perhaps it might be your best choice in the urban jungle.

If you’re curious about LoRaWAN, you might want to start closer to home and sniff for local activity.