Simple Decoder Serves as Solo Ham’s Test Buddy

For a hobby that’s ostensibly all about reaching out to touch someone, ham radio can often be a lonely activity. Lots of hams build and experiment with radio gear much more than they’re actually on the air, improving their equipment iteratively. The build-test-tweak-repeat cycle can get a little tedious, though, especially when you’re trying to assess signal strength and range and can’t find anyone to give you a report.

To close the loop on field testing, [WhiskeyTangoHotel] threw together a simple ham radio field confirmation unit that’s pretty slick. It relies on the fact that almost every ham radio designed for field use incorporates a DTMF encoder in the microphone or in the transceiver itself. Hams have used Touch Tones for in-band signaling control of their repeaters for decades, and even as newer digital control methods have been introduced, good old analog DTMF hangs in there. The device consists of a DTMF decoder attached to the headphone jack of a cheap handy talkie. When a DTMF tone is received, a NodeMCU connected to the decoder calls an IFTTT job to echo the key to [WTH]’s phone as an SMS message. That makes it easy to drive around and test whether his mobile rig is getting out. And since the receiver side is so portable, there’s a lot of flexibility in how tests can be arranged.

On the fence about ham as a hobby? We don’t blame you. But fun projects like this are the perfect excuse to go get licensed and start experimenting.

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Storm Detector Modules: Dancing in the Rain

Earlier, we had covered setting up an AS3935 lightning detector module. This detector picks up radio emissions, then analyzes them to determine if they are a lightning strike or some other radio source. After collecting some data, it outputs the estimated distance to the incoming storm front.

But that only gets you halfway there. The device detects many non-lightning events, and the bare circuit board is lacking in pizzazz. Today I fix that by digging into the detector’s datasheet, and taking a quick trip to the dollar store buy a suitable housing. The result? A plastic plant that dances when it’s going to rain!
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An Introduction to Storm Detector Modules

Lightning storm detectors have been around for a surprisingly long time. The early designs consisted of a pair of metal bells and a pendulum. When there was a charge applied, for example by connecting one bell to the ground and the other to a lightning rod, the bells would ring when a lightning storm was close by. In the mid 18th century, these devices were only practical for demonstration and research purposes, but very likely represent the earliest devices that convert electrostatic charge to mechanical force. A bit over a hundred years later, the first lightning detector was considered by some as the first radio receiver as well.

As soon as I found out about storm detector chips, I knew I would have to get one working. For about $25, I ordered an AMS AS3935 module from China. This chip has been featured before in a number of excellent projects such as Twittering lightning detectors, and networks of Sub-Saharan weather stations. While there’s an Arduino library for interfacing with this IC, I’m going to be connecting it up to an ESP8266 running the NodeMCU firware, which means digging into the datasheet and writing some SPI code. If any of the above tickles your fancy, read on! Continue reading “An Introduction to Storm Detector Modules”

Traction Control Gets More Power to the Road for Tot-Sized Lamborghini

We’ve all heard the complaints from oldsters: “Cars used to be so simple that all you needed to fix them was a couple of wrenches and a rag. Now, you need a computer science degree to even pop the hood!” It’s true to some extent, but such complexity is the cost of progress in the name of safety and efficiency. And now it seems this complexity is coming way down-market, with this traction control system for a Power Wheels Lamborghini.

While not exactly an entry-level model from the Power Wheels line of toddler transportation, the pint-sized Lamborghini Aventador [Jason] bought for his son had a few issues. Straight from the factory, its 6-volt drivetrain was a little anemic, with little of the neck-snapping acceleration characteristic of an electric drive. [Jason] opted to replace the existing 6-volt drive with a 12-volt motor and battery while keeping the original 6-volt controller in place. The resulting rat’s nest of relays was unsightly but sufficient to see a four-fold increase in top speed.

With all that raw power sent to only one wheel, though, the Lambo was prone to spinouts. [Jason] countered this with a traction control system using optical encoders on each of the rear wheels. A NodeMCU senses speed differences between the wheels and controls the motor through an H-bridge to limit slipping. As a bonus, a smartphone app can connect to the Node for in-flight telemetry. Check out the build and the car being put through its paces by the young [Mr. Steal Your Girl] in the video below.

The Power Wheels platform is infinitely hackable – from repairs to restorations to enhancements of questionable sanity, it seems like there’s nothing you can’t do with these little electric vehicles.

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Massive Shift Register Switches Lights

Sometimes you have to switch a light. Maybe it’s an LED but sometimes it’s mains-powered. That’s not too hard, a transistor and a relay should do it. If you have to switch more lights, that’s not too bad either, as long as your microcontroller has enough free GPIOs. But, if you need to switch a large number of lights, like 256 of them, for example, you’re going to need something else.

[Jan]’s project didn’t switch quite that many lights, but 157 of them is still enough of a chore to need a creative solution so he decided to use a 256-bit shift register to do the legwork. The whole thing is powered by a NodeMCU ESP8266 and was professionally built on DIN rails in a metal enclosure.

The build is interesting, both from a technical point of view and from an artistic one. It looks like it uses more than a mile of wiring, too. The source code is also available on the project page if you happen to have a need for switching a huge number of lightbulbs. Incandescent blulbs aren’t only good for art installations and lamps, though, they can also be used in interesting oscillator circuits too.

Look Out Nest — Here Comes the WIoT-2

[Dave] is an avid hacker and no stranger to Hackaday. When he decided to give his IoT weather display an upgrade, he pulled out all the stops.

The WIoT-2 is less of a weather station and more of an info center for their house — conveniently located by their front door — for just about anything [Dave] or his partner need to know when entering or exiting their home. It displays indoor temperature and humidity, date, time, garbage collection schedule, currency exchange rates, whether the garage door is open or closed, the hot tub’s temperature, a check in for his kids, current weather data from a custom station [Dave] built outside his house, and the local forecast.

WIoT-2’s display is a Nextion TFT and the brains behind the operation is a NodeMCU 8266. He made extensive use of Blynk to handle monitoring of the various feeds, and will soon be integrating master control for all the networked outlets in the house into the system. He found setting up the hardware to be fairly clear-cut but notes that he cannot have the screen powered on when uploading sketches to the NodeMCU.  He circumvented the problem by adding a latching switch to the screen’s power line.

[Dave] curated a robust explanation of his build that includes tips, tricks, code — and a how-to to boot! If you’re not already starting your own build of this info suite, you may be tantalized by some of his other projects.

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Monitor Power Consumption of Low-Power Devices

Perhaps the most important consideration to make when designing a battery-operated device of any kind is the power consumption. Keeping it running for longer between battery changes is often a key design point. To that end, if you need to know how small programming changes will impact the power consumption of your device then [Daniel] has a great tool that you might find helpful: an ESP8266-based live power meter.

The power meter itself is battery-powered via a 600 mAh battery and monitors an e-paper module, which also displays information about power consumption. It runs using a NodeMCU and measures voltage and current across a 100-ohm resistor to calculate the power use, although the resolution does start to get noisy when the device is in standby/sleep mode. One presumes this could be solved by changing the value of the resistor in order to get more accurate measurements at the expense of losing accuracy during moments of high power consumption.

While this power monitor was built specifically to monitor power consumption on this particular e-paper display project, it should be easily portable into other battery-based systems that need fine tuning in order to maximize battery life. As a bonus, the display is already included in the project. There are ways of getting even more information about your battery usage, although if power consumption is important than you may want to stick with a more straightforward tool like this one.