Single Flex PCB Folds Into A Four-Wheel Rover, Complete With Motors

March 25, 2023 by Dan Maloney 3 Comments

You’ve got to hand it to [Carl Bugeja] — he comes up with some of the most interesting electromechanical designs we’ve seen. His latest project is right up there, too: a single PCB that folds up into a four-wheel motorized rover.

The key to [Carl]’s design lies with his PCB brushless motors, which he has been refining since we first spotted them back in 2018. The idea is to use traces on the PCB for the stator coils to drive a 3D printed rotor containing tiny magnets. They work surprisingly well, even if they don’t generate a huge amount of torque. [Carl]’s flexible PCB design, which incorporates metal stiffeners, is a bit like an unfolded cardboard box, with two pairs of motor coils on each of the side panels. This leaves the other surfaces available for all the electronics, with includes a PIC, a driver chip, and a Hall sensor for each motor, an IMU and proximity sensor for navigation, and an ESP32 to run the show.

With machined aluminum rotors and TPU tires mounted to the folded-up chassis, it was off to the races, albeit slowly. The lack of torque from the motors and the light weight of the rover, along with some unwanted friction due to ill-fitting joints, added up to slow progress, especially on anything other than a dead flat surface. But with some tweaking, [Carl] was able to get the buggy working well enough to call this one a win. Check out the build and testing in the video below.

Knowing [Carl], this isn’t the last we’ll see of the foldable rover. After all, he stuck with his two-wheel PCB motor design and eventually got that running pretty well. We’ll be keeping an eye out for progress on this one.

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Creating GIFs For The Channels Between Channels

March 17, 2023 by Matthew Carlson 4 Comments

In the United States, analog TV broadcasting officially ended in 2009. While the transition wasn’t without hiccups, we did lose something along the way. For [Emily Velasco], she misses the channels between channels — where an analog TV isn’t quite tuned right and the image is smeared and distorted. A recent bug in one of her projects led to her trying to recreate the experience of the in-between on a CRT.

One of [Emily]’s other projects involved generating composite video signals from an ESP32 microcontroller. While experimenting with adding color to the output signal, the image came out incredibly scrambled. She had made an error in the stride, which smeared the image across the screen. This immediately brought back memories of old analog TV sets. A quick potentiometer allowed her to control the stride error and she wrote some code to break the GIF up into discrete bitmaps for display since the GFX library handles GIFs differently than static images. Next up was vertical hold, which was accomplished by shifting the Y coordinates. With some help from [Roger], there was now a handy GIF library that would draw GIFs line by line with the composite video effects.

She used a Goldbeam portable CRT, soldered the tuning potentiometer to the ESP32, and set up 10 different GIFs to act as “channels” with space in between. It’s a fun and quirky idea, which is exactly the sort of thing [Emily] has been encouraging people to do.

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The International Space Station Is Always Up There

March 15, 2023 by Bryan Cockfield 9 Comments

Thanks to its high orbital inclination, the International Space Station (ISS) eventually passes over most inhabited parts of the Earth. Like other artificial satellites, though, it’s typically only visible overhead during passes at sunrise and sunset. If you’d like to have an idea of where it is beyond the times that it’s directly visible, take a look at this tabletop ISS tracking system created by [dpelgrift].

The tracker uses an Adafruit Feather inside its enclosure along with a Featherwing ESP32 WiFi co-processor. Together they direct a 3D printed rocket-shaped pointing device up and down by way of a SG90 micro-servo, while a 28BYJ-48 stepper motor provides rotation.

This setup allows it to take in all of the information required to calculate the Station’s current position. The device uses the current latitude and longitude, as well as its compass heading, and combines that with data pulled off the net to calculate which direction it should be pointing.

While it might seem like a novelty or programming challenge, this project could be useful for plenty of people who just want to keep track so they know when to run outside and see the Station pass by, or even by those who use the radio repeater aboard the ISS. The repeater on the ISS and plenty of other satellites are available to amateur radio operators for long-distance VHF and UHF communication like we’ve seen in projects like these.

Pocket-Sized Thermal Imager

March 14, 2023 by Bryan Cockfield 25 Comments

Just as the gold standard for multimeters and other instrumentation likely comes in a yellow package of some sort, there is a similar household name for thermal imaging. But, if they’re known for anything other than the highest quality thermal cameras, it’s excessively high price. There are other options around but if you want to make sure that the finished product has some sort of quality control you might want to consider building your own thermal imaging device like [Ruslan] has done here.

The pocket-sized thermal camera is built around a MLX90640 sensor from Melexis which can be obtained on its own, but can also be paired with an STM32F446 board with a USB connection in order to easily connect it to a computer. For that, [Ruslan] paired it with an ESP32 board with a companion screen, so that the entire package could be assembled together with a battery and still maintain its sleek shape. The data coming from the thermal imagining sensor does need some post-processing in order to display useful images, but this is well within the capabilities of the STM32 and ESP32.

With an operating time on battery of over eight hours and a weight under 100 grams, this could be just the thing for someone looking for a thermal camera who doesn’t want to give up an arm and a leg to one of the industry giants. If you’re looking for something even simpler, we’ve seen a thermal camera based on a Raspberry Pi that delivers its images over the network instead of on its own screen.

Supercon 2022: Irak Mayer Builds Self-Sustainable Outdoor IoT Devices

March 13, 2023 by Dave Rowntree 4 Comments

[Irak Mayer] has been exploring IoT applications for use with remote monitoring of irrigation control systems. As you would expect, the biggest challenges for moving data from the middle of a field to the home or office are with connectivity and power. Obviously, the further away from urbanization you get, the sparser both these aspects become, and the greater the challenge.

[Irak] solves his connectivity problem by assuming there is some WiFi network within range, building a system around the Blues Wireless WiFi note card. Substituting their cellular card would be an option for applications out of WiFi range, but presumably without changing too much on the system and software side of things. Leveraging the Adafruit FeatherWing INA219, which is a bidirectional current sensor with an I²C interface, for both the power generation and system consumption measurements. For control, [Irak] is using an Adafruit ESP32 board, but says little more about the hardware. On the software side, [Irak] is using the Blues Wireless NoteHub for the initial connection, which then routes the collected data onto the Adafruit IoT platform for collation purposes. The final part of the hardware is a LiPo battery which is on standby to soak up any excess power available from the energy harvesting. This is monitored by an LC709203f battery fuel gauge.

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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.

Sneaky Clock Displays Wrong Time If It Catches You Looking

February 23, 2023 by Donald Papp 20 Comments

We have a soft spot for devices that subvert purpose and expectation, and that definitely sums up [Guy Dupont]’s Clock That Is Wrong. It knows the correct time, but whether or not it displays the correct time is another story. That’s because nestled just above the 7-segment display is a person sensor module, and when it detects that a person is looking towards it, the clock will display an incorrect time, therefore self-defeating both the purpose and primary use case of a clock in one stroke.

The person sensor is a tiny board with tiny camera that constantly does its best to determine whether a person is in view, and whether they are looking towards the sensor. It’s a good fit for a project like this, and it means that one can look at the clock from an oblique angle (meaning one is out of view of the sensor) and see the correct time. But once one moves in front of it, the time changes. You can watch a brief video of it in action in this Twitter thread.

One interesting bit is that [Guy] uses an ESP32-based board to drive everything, but had some reservations about making a clock without an RTC. However, he found that simply syncing time over the network every 10 minutes or so using the board’s built-in WiFi was perfectly serviceable, at least for a device like this.

This reminds us a little of other clocks with subtly subversive elements, like the Vetinari Clock which keeps overall accurate time despite irregularly drifting in and out of sync. Intrigued by such ideas? You’re not alone, because there are even DIY hobby options for non-standard clock movements. Adding the ability to detect when someone is looking directly at such a device opens up possibilities, so keep it in mind if it’s time for a weekend project.