Low-Power Wi-Fi Includes E-Paper Display

March 10, 2023 by Bryan Cockfield 6 Comments

Designing devices that can operate in remote environments on battery power is often challenging, especially if the devices need to last a long time between charges or battery swaps. Thankfully there are some things available that make these tasks a little easier, such as e-ink or e-paper displays which only use power when making changes to the display. That doesn’t solve all of the challenges of low-power devices, but [Albertas] shows us a few other tricks with this development board.

The platform is designed around an e-paper display and is meant to be used in places where something like sensor data needs to not only be collected, but also displayed. It also uses the ESP32C3 microcontroller as a platform which is well-known for its low power capabilities, and additionally has an on-board temperature and humidity sensor. With Bluetooth included as well, the tiny device can connect to plenty of wireless networks while consuming a remarkably low 34 µA in standby.

With a platform like this that can use extremely low power when not taking measurements, a battery charge can last a surprisingly long time. And, since it is based on common components, adding even a slightly larger battery would not be too difficult and could greatly extend this capability as well. But, we have seen similar builds running on nothing more than a coin cell, so doing so might only be necessary in the most extreme of situations.

Linux Fu: Sharing Your Single WiFi

February 22, 2023 by Al Williams 24 Comments

If you are trying to build a router or access point, you’ll need to dig into some of the details of networking that are normally hidden from you. But, for a normal WiFi connection, things mostly just work, even though that hasn’t always been the case. However, I ran into a special case the other day where I needed a little custom networking, and then I found a great answer to automate the whole process. It all comes down to hotel WiFi. How can you make your Linux laptop connect to a public WiFi spot and then rebroadcast it as a private WiFI network? In particular, I wanted to connect an older Chromecast to the network.

Hotel WiFi used to be expensive, but now, generally, it is free. There was a time when I carried a dedicated little box that could take a wired or wireless network and broadcast its own WiFi signal. These were actually fairly common, but you had to be careful as some would only broadcast a wired network connection. It was more difficult to make the wireless network share as a new wireless network, but some little travel routers could do it. Alternatively, you could install one of the open router firmware systems and set it up. But lately, I haven’t been carrying anything like that. With free WiFi, you can just connect your different devices directly to the network. But then there’s the Chromecast and the dreaded hotel login.

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A Commodore 64 accessing an online service

The WiC64 Brings Classic Commodores Online, Google Maps Included

February 4, 2023 by Robin Kearey 29 Comments

A computing platform is never really dead unless people stop developing new software for it. By that measure, the Commodore 64 is alive and well: new games, demos, and utilities are still being released on a regular basis. Getting those new programs onto an old computer was always a bit of a hassle though, requiring either an SD card adapter for the Commodore or a direct cable connection from an internet-connected PC. Luckily, there’s now a simpler way to get your latest software updates thanks to a WiFi adapter called WiC64. This adapter plugs into the expansion port of a classic Commodore and lets you download programs directly into memory. [Tommy Ovesen] over at [Arctic Retro] bought one and explored its many features.

The basic design of the WiC64 is straightforward: an ESP32 mounted on an adapter board that connects its data bus to that of the Commodore 64, 128 or VIC-20. A simple program, which you still need to transfer the old way, lets you configure the device and connect to a WiFi network. Once that’s done, an interactive BBS-style program is launched that allows you to access a range of online services. The WiC64 developers provide these, but since the system is fully open-source there’s nothing stopping you from running your own servers as well.

Services currently available include an RSS reader, several multiplayer online games, and even a radio station that plays non-stop SID tunes. There’s also a direct link to CSDB, an online database of Commodore 64 programs and demos which you can now simply download and run directly on your C64 – in effect, a modern app store for a classic computer.

One feature that really seems to defy the C64’s hardware limitations is a fully functional version of Google Maps. Even with the Commodore’s limited resolution and color depth, it does a pretty decent job of showing maps, satellite photos, and even Street View images.

Using the WiC64 requires no hardware modifications to the Commodore 64, but a custom ROM is available that enables a few convenient features such as LOADing programs directly from a web address. There have been several attempts at getting classic Commodores online, but none so far that managed to get complex apps like Google Maps running. We have seen YouTube videos being played on a Commodore PET though.

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Four images in one. Top left is an image of four individuals in a room with whiteboards and desks in the background along with various clutter on the floor. Over the people is a wireframe overlay of their poses. The image on the top right is just the wireframe people on a black background. Bottom left image is of a single individual standing in a room with the pose wireframe overlay. Bottom right image is the single pose wireframe on a black background.

Tracking Humans With WiFi

January 26, 2023 by Navarre Bartz 46 Comments

In case you thought that cameras, LiDAR, infrared sensors, and the like weren’t enough for Big Brother to track you, researchers from Carnegie Mellon University have found a way to track human movements via WiFi. [PDF via VPNoverview]

The process uses the signals from WiFi routers for an inexpensive way to determine human poses that isn’t hampered by lack of illumination or object occlusion. The system produces UV coordinates of human bodies by analyzing signal strength and phase data to generate a 2D feature map and then feeding that through a modified DensePose-RCNN architecture which corresponds to 3D human poses. The system does have trouble with unusual poses that are not in the training set or if there are more than three subjects in the detection area.

While there are probably applications in Kinect-esque VR Halo games, this will probably go straight into the toolbox of three letter agencies and advertising-fueled tech companies. The authors claim this to use “privacy-preserving algorithms for human sensing,” but only time will tell if they’re correct.

If you’re interested in other creepy surveillance tools, checkout the Heat-Sensing Crotch Monitor or this Dystopian Peep Show.

A small brown PCB with various components on it. There is a headphone cable and DC barrel connector cable coming out of it.

Put Your Serial Port On The Web

January 7, 2023 by Navarre Bartz 37 Comments

Today, everything from your computer to your dryer has wireless communications built in, but devices weren’t always so unencumbered by wires. What to do when you have a legacy serial device, but no serial port on the computer you want to connect? [vahidyou] designed a wireless serial dongle to solve this conundrum.

Faced with a CNC that took instructions over serial port, and not wanting to deal with the cabling involved in a serial to USB adapter, [vahidyou] turned to an ESP8266 to let his computer and device talk wirelessly. The hand-made PCB connects via a 3.5 mm headphone jack to DB9 adapter which he describes in another article. While [vahidyou] did write a small Windows program for managing the device, it is probably easier to simply access it in a web browser from any device you have handy.

Want to see another wireless serial port application? This Palm Portable Keyboard Bluetooth dongle will let you type in comfort on the go, or you can use a PiModem to get your retrocomputer online!

This WiFi Signal Strength Meter Ain’t Afraid Of No Ghosts

December 23, 2022 by Dan Maloney 5 Comments

The original Ghostbusters movie is a classic that’s still delivering nearly 40 years after its release — just let that sink in for a minute. Almost every aspect of the film, from hand props to quotes, is instantly recognizable, even to people who haven’t based their lives on the teachings of [Venkman], [Stantz], and [Spengler]. To wit, we present this PKE meter-style WiFi scanner.

Of course, [Kevin McAleer]’s project is strictly in the “Just for Fun” category. But that doesn’t mean it’s not at least somewhat useful. The design is pretty close to the original PKE meter, with a little bit of creative license taken to make it easier to build. Guts include a Raspberry Pi Pico W and a generous 320×240 LCD display. The body of the meter is entirely 3D printed; design files are of course available. The meter’s arms are geared together to move with a single hobby servo.

On the software side, [Kevin]’s GUI lets users see a list of WiFi hotspots in the area and select one from the list. From there, the position of the arms is determined by the RSSI for the hotspot, similar to how the prop was supposed to indicate the proximity to a spook, specter, or ghost. There’s perhaps a bit of a missed opportunity by not adding LEDs to the arms, but we’ll let that slide.

The video below has full design and build details, but fair warning that it’s a bit on the long side. That’s probably just a reflection of how much work [Kevin] put into this, though. Of course, you may rather build a PKE meter that “actually” detects ghosts, in which case we’ve got you covered.

Continue reading “This WiFi Signal Strength Meter Ain’t Afraid Of No Ghosts” →

Snail Mail Notifier’s Simple Power Management To Maximize Battery Life

December 19, 2022 by Donald Papp 33 Comments

There are no weird, specialized components nor esoteric sleep mode tricks behind the long battery life of [Zak]’s WiFi mail slot watcher. Just some sensible design and clever focus on the device’s purpose: to send an HTTP request whenever it detects that the front door’s mail slot has been opened. The HTTP request is what kicks off useful notifications, but it’s the hardware design that’s really worth a peek.

The watcher’s main components are a ESP-M2 WiFi module, a reed switch, and a single lithium cell. Here’s how it works at a high level: when the mail slot is opened (detected by the reed switch), the ESP module is powered up just long enough to connect to the local WiFi network and send a single HTTP request, after which it shuts back down. The whole process takes between four and ten seconds.

As mentioned, the power control isn’t managed by any unusual components; it comes down to a NAND gate with a single inverted input, and a MIC5504 3.3 V regulator responsible for feeding the ESP board. The logic gate controls whether the voltage regulator is enabled or disabled, and therefore whether the microcontroller receives any power at all. Most of the time the regulator is disabled, but when the reed switch triggers, its input to the NAND gate is pulled low and the regulator is turned on, booting up the ESP board.

In order to stay on, the first thing the ESP board does is use a GPIO pin to drive the inverted input of the NAND gate high in order to keep the regulator enabled, and it has a window of about half a second to do this. Once the HTTP request is sent (and the battery voltage sensed), the ESP board pulls that pin low, disabling the regulator and turning itself off until the reed switch once again begins the process.

After seven months of use, the battery has dropped from 4.2 V to 3.9 V, so there’s plenty of life left. The project’s GitHub repository has the necessary code if you’d like to apply some of its ideas to your own projects. Alternately, you may wish to consider supercapacitors and solar in lieu of batteries. Even if ultra-level power savings isn’t your bag, when WiFi and networking is involved, there are software-level opportunities to be more efficient. Even a judicious 1 ms delay can save a surprising amount of power in the right circumstances.