Library Makes ESP Over The Air Updates Easy

March 21, 2019 by Al Williams 19 Comments

Potentially, one of the great things about having a device connected to the network is that you can update it remotely. However, how do you make that happen? If you use the Arduino setup for the ESP8266 or ESP32, you might try [scottchiefbaker’s] library which promises to make the process easy.

Adding it looks to be simple. You’ll need an include, of course. If you don’t mind using port 8080 and the path /webota, you only need to call handle_webota() from your main loop. If you want to change the defaults, you’ll need to add an extra call in your setup. You also need to set up a few global variables to specify your network parameters.

Continue reading “Library Makes ESP Over The Air Updates Easy” →

DIY Six Channel Arduino RC Transmitter

March 19, 2019 by Tom Nardi 11 Comments

It’s wasn’t so long ago that RC transmitters, at least ones worth owning, were expensive pieces of gear. Even more recently than that, the idea of an RC transmitter running an open source firmware would have been considered a pipe dream. Yet today buying cheap imported transmitters and flashing a community developed firmware (if it didn’t come with it pre-installed to begin with) is common place. It’s not much of a stretch to say we’re currently in the “Golden Age” of hobby RC transmitters.

But what if even cheap hardware running customizable software isn’t enough? What if you want to take it to the next level? In that case, [Electronoobs] has an Arduino powered RC transmitter with your name on it. But this is no scrap of protoboard with a couple of cheap joysticks on it, though he has made one of those too. The goal of this build was for it to look and perform as professional as possible while remaining within the hobbyist’s capabilities. The final product probably won’t be winning any design awards, but it’s still an impressive demonstration of what the individual hacker and maker can pull off today with the incredible technology we have access to.

So what goes into this homebrew radio control system? Inside the back panel [Electronoobs] mounted the batteries, charging module, and the voltage regulator which steps the battery voltage down to the 3.3 V required to drive the rest of the transmitter’s electronics. On the flip side there’s an Arduino Nano, an NRF24 module, and an OLED display. Finally we have an assortment of switches, buttons, potentiometers, and two very nice looking JH-D202X-R2 joysticks for user input.

As you might have guessed, building your own transmitter means building your own receiver as well. Unfortunately you won’t be able to bind your existing RC vehicles to this radio, but since the receiver side is no more complicated than another Arduino Nano and NRF24 module, it shouldn’t be hard to adapt them if you were so inclined.

Low-cost consumer RC transmitters can be something of a mixed bag. There are some surprisingly decent options out there, but it’s not a huge surprise that hackers are interested in just spinning up their own versions either.
Continue reading “DIY Six Channel Arduino RC Transmitter” →

Es’hail-2: Hams Get Their First Geosynchronous Repeater

March 18, 2019 by Dan Maloney 27 Comments

In the radio business, getting the high ground is key to covering as much territory from as few installations as possible. Anything that has a high profile, from a big municipal water tank to a roadside billboard to a remote hilltop, will likely be bristling with antennas, and different services compete for the best spots to locate their antennas. Amateur radio clubs will be there too, looking for space to locate their repeaters, which allow hams to use low-power mobile and handheld radios to make contact over a vastly greater range than they could otherwise.

Now some hams have claimed the highest of high ground for their repeater: space. For the first time, an amateur radio repeater has gone to space aboard a geosynchronous satellite, giving hams the ability to link up over a third of the globe. It’s a huge development, and while it takes some effort to use this new space-based radio, it’s a game changer in the amateur radio community.

Continue reading “Es’hail-2: Hams Get Their First Geosynchronous Repeater” →

EBay Modules And Custom PCBs Make A Plug And Play Ham Transceiver

March 17, 2019 by Dan Maloney 9 Comments

Many of us have fond memories of our introduction to electronics through the “200-in-1” sets that Radio Shack once sold, or even the more recent “Snap Circuits”-style kits. Most of eventually us move beyond these kits to design our circuits; still, there’s something to be said for modular designs. This complete amateur radio transceiver is a great example of that kind of plug and play construction.

The rig is the brainchild of [jmhrvy1947], who set out to build a complete transceiver using mostly eBay-sourced modules. Some custom PCBs are used, but those are simple boards that can be etched and drilled easily. The transceiver is only for continuous-wave (CW) use, which would normally mean you’d need to know Morse, but thanks to some clever modifications to open-source apps like Quisk and FLDigi, Morse can be received and sent directly from the desktop. That will no doubt raise some hackles, but we think it’s a great way to learn code. The rig is QRP, or low power, transmitting only 100 mW with the small power amp shown. Adding eBay modules can jack that up to a full 100 Watts, which also requires adding a 12-volt power supply, switchable low-pass filters, a buck-boost converter, and some bandpass filters for band selection. It ends up looking very experimental, but it works well enough to make contacts.

We really like the approach here, and the fact that the rig can be built in stages. That makes it a perfect project for our $50 Ham series, which just kicked off. Perhaps we’ll be seeing it again soon.

Continue reading “EBay Modules And Custom PCBs Make A Plug And Play Ham Transceiver” →

The $50 Ham: Entry-Level Transceivers For Technicians

March 15, 2019 by Dan Maloney 95 Comments

Last week , I covered the ridiculously low barriers to entry to amateur radio, both in terms of financial outlay and the process of studying for and passing the FCC examination. You’ve had seven days, so I assume that you’ve taken the plunge and are a freshly minted amateur radio operator. The next big question may be: Now what?

We briefly mentioned the image that ham radio is a rich old person’s hobby, and that reputation is somewhat deserved. For ham gear, there really is no upper limit on what you can spend. Glossy brochures and slick web pages hawk transceiver bristling with knobs and switches and loaded with the latest features, all of which will probably be obsolete within a few years when the Next Big Thing comes along and manufacturers respond with new, must-have models – looking at you, ICOM IC-7300. It’s no different than any other technology market, and enough people fall for that marketing to make it a going concern.

But thankfully, while there is no apparent ceiling on what you can spend on ham gear, there certainly is a floor, and it can be very, very low. Our $50 budget can go quite a long way to getting a new Technician on the air, if you’re willing to make some compromises and can forego the latest and greatest for a while.

Continue reading “The $50 Ham: Entry-Level Transceivers For Technicians” →

The $50 Ham: Getting Your Ticket Punched

March 8, 2019 by Dan Maloney 118 Comments

Today we start a new series dedicated to amateur radio for cheapskates. Ham radio has a reputation as a “rich old guy” hobby, a reputation that it probably deserves to some degree. Pick up a glossy catalog from DX Engineering or cruise their website, and you’ll see that getting into the latest and greatest gear is not an exercise for the financially challenged. And thus the image persists of the recent retiree, long past the expense and time required to raise a family and suddenly with time on his hands, gleefully adding just one more piece of expensive gear to an already well-appointed ham shack to “chew the rag” with his “OMs”.

Not a $50 ham. W9EVT’s shack. Source: QRZ.com

As I pointed out a few years back in “My Beef With Ham Radio”, I’m an inactive ham. My main reason for not practicing is that I’m not a fan of talking to strangers, but there’s a financial component to my reticence as well – it’s hard to spend a lot of money on gear when you don’t have a lot to talk about. I suspect that there are a lot of would-be hams out there who are turned off from the hobby by its perceived expense, and perhaps a few like me who are on the mic-shy side.

This series is aimed at dispelling the myth that one needs buckets of money to be a ham, and that jawboning is the only thing one does on the air. Each installment will feature a project that will move you further along your ham journey that can be completed for no more than $50 or so. Wherever possible, I’ll be building the project or testing the activity myself so I can pursue my own goal of actually using my license for a change.

Continue reading “The $50 Ham: Getting Your Ticket Punched” →

Does WiFi Kill Houseplants?

February 28, 2019 by Dan Maloney 72 Comments

Spoiler alert: No.

To come to that conclusion, which runs counter to the combined wisdom of several recent YouTube videos, [Andrew McNeil] ran a pretty neat little experiment. [Andrew] has a not inconsiderable amount of expertise in this area, as an RF engineer and prolific maker of many homebrew WiFi antennas, some of which we’ve featured on these pages before. His experiment centered on cress seeds sprouting in compost. Two identical containers were prepared, with one bathed from above in RF energy from three separate 2.4 GHz transmitters. Each transmitter was coupled to an amplifier and a PCB bi-quad antenna to radiate about 300 mW in slightly different parts of the WiFi spectrum. Both setups were placed in separate rooms in east-facing windows, and each was swapped between rooms every other day, to average out microenvironmental effects.

After only a few days, the cress sprouted in both pots and continued to grow. There was no apparent inhibition of the RF-blasted sprouts – in fact, they appeared a bit lusher than the pristine pot. [Andrew] points out that it’s not real science until it’s quantified, so his next step is to repeat the experiment and take careful biomass measurements. He’s also planning to ramp up the power on the next round as well.

We’d like to think this will put the “WiFi killed my houseplants” nonsense to rest – WiFi can even help keep your plants alive, after all. But somehow we doubt that the debate will die anytime soon.

Continue reading “Does WiFi Kill Houseplants?” →