Commercial industrial agriculture is responsible for providing food to the world’s population at an incredibly low cost, especially when compared to most of human history when most or a majority of people would have been involved in agriculture. Now it’s a tiny fraction of humans that need to grow food, while the rest can spend their time in cities and towns largely divorced from needing to produce their own food to survive. But industrial agriculture isn’t without its downsides. Providing inexpensive food to the masses often involves farming practices that are damaging to the environment, whether that’s spreading huge amounts of synthetic, non-renewable fertilizers or blanket spraying crops with pesticides and herbicides. [NathanBuildsDIY] is tackling the latter problem, using an automated drone system to systemically target weeds to reduce his herbicide use.
The specific issue that [NathanBuildsDIY] is faced with is an invasive blackberry that is taking over one of his fields. To take care of this issue, he set up a drone with a camera and image recognition software which can autonomously fly over the field thanks to Ardupilot and a LiDAR system, differentiate the blackberry weeds from other non-harmful plants, and give them a spray of herbicide. Since drones can’t fly indefinitely, he’s also build an automated landing pad complete with a battery swap and recharge station, which allows the drone to fly essentially until it is turned off and uses a minimum of herbicide in the process.
The entire setup, including drone and landing pad, was purchased for less than $2000 and largely open-source, which makes it accessible for even small-scale farmers. A depressing trend in farming is that the tools to make the work profitable are often only attainable for the largest, most corporate of farms. But a system like this is much more feasible for those working on a smaller scale and the automation easily frees up time that the farmer can use for other work. There are other ways of automating farm work besides using drones, though. Take a look at this open-source robotics platform that drives its way around the farm instead of flying.
The BMW i3 debuted on the market in late 2013, one of the brand’s first electric cars. Also available with an optional range-extending engine, early models featured a 60 Ah battery providing up to 130km range on a full charge. However, times have changed, and over the years, BMW have updated the model with larger capacity batteries over the years. So what does it take to retrofit an older model with the newer, fatter, juicer 120 Ah pack?
It’s all helpfully laid out in a video by [Daniel], who notes that it’s not a job for the faint of heart or poorly equipped. The good news is that, mechanically, the newer batteries have the same external dimensions as the older packs, meaning they can be bolted in without requiring any cutting, welding or, adapters. But that’s about it for the good news. The batteries are cooled by the air conditioning system, meaning that removal and replacement means draining the system of refrigerant using highly expensive specialised hardware. Additionally, many batteries in crashed cars are disabled when the airbags are triggered for safety reasons, requiring unlocking through BMW’s proprietary software or replacement of the internal battery controller. Then there’s the usual laundry list of gradual changes that happen across any automotive line, meaning that certain model years and trim packages can have incompatible plugs and connectors or other features.
Overall, it can be quite a bit of work to do, and with the tools required, something that needs the services of a dedicated mechanic’s workshop. However, find an experienced shop that regularly works with EVs, and you might find they can facilitate the upgrade for you without too much fuss. We’ve seen [Daniel] tackle upgrades before, such as a much easier swap on the Nissan Leaf. Video after the break.
Anyone who enjoys opening up consumer electronics knows iFixit to be a valuable resource, full of reference pictures and repair procedures to help revive devices and keep them out of electronic waste. Champions of reparability, they’ve been watching in dismay as the quest for thinner and lighter devices also made them harder to fix. But they wanted to cheer a bright spot in this bleak landscape: increasing use of stretch-release adhesives.
Once upon a time batteries were designed to be user-replaceable. But that required access mechanisms, electrical connectors, and protective shells around fragile battery cells. Eliminating such overhead allowed slimmer devices, but didn’t change the fact that the battery is still likely to need replacement. We thus entered into a dark age where battery pouches were glued into devices and replacement meant fighting clingy blobs and cleaning sticky residue. Something the teardown experts at iFixit are all too familiar with.
This is why they are happy to see pull tabs whenever they peer inside something, for those tabs signify the device was blessed with stretch-release adhesives. All we have to do is apply a firm and steady pull on those tabs to release their hold leaving no residue behind. We get an overview of how this magic works, with the caveat that implementation details are well into the land of patents and trade secrets.
But we do get tips on how to best remove them, and how to reapply new strips, which are important to iFixit’s mission. There’s also a detour into their impact on interior design of the device: the tabs have to be accessible, and they need room to stretch. This isn’t just a concern for design engineers, they also apply to stretch release adhesives sold to consumers. Advertising push by 3M Command and competitors have already begun, reminding people that stretch-release adhesive strips are ideal for temporary holiday decorations. They would also work well to hold batteries in our own projects, even if we aren’t their advertised targets.
Our end-of-year gift-giving traditions will mean a new wave of gadgets. And while not all of them will be easily repairable, we’re happy that this tiny bit of reparability exists. Every bit helps to stem the flow of electronics waste.
You’d be forgiven for not realizing there’s still a diehard group of people out there carrying around dedicated MP3 players. While they were all the rage a decade or so back, most consumers have since moved over to using their handy dandy pocket supercomputer for playing their music. Plus controlling every other aspect of their personal life and finances, of course. Though that’s another story entirely.
But as [Conno Brooks] explained to us, there’s a sizable group of open source fanatics who prefer to store their jams on devices running the Rockbox firmware. Only problem is, some of the desirable Rockbox-compatible players are from the Golden Age of dedicated players, and aren’t getting any younger. In a recent blog post, he briefly goes over his ultimately successful attempt to put a new-made battery into his Sansa Clip+, a particularly desirable player that was released in 2009.
There are a few problems with the procedure that has kept it from being very widespread, according to [Conno]. For one, the Sansa Clip+ is tiny and not easily disassembled without destroying it. Worse, the diminutive 30mm x 36mm x 3mm OEM battery is effectively unobtainium. But ironically he was able to find an even smaller battery which seemed like it should work, assuming he could get it wired up.
The OEM battery on the Clip+ uses three wires, which [Conno] presumed was part of some thermal protection system. He first tried to take the circuit board off the original dead battery and graft it onto the modern cell, but something must have tripped because the resulting Franken-pack didn’t output any voltage. On his second attempt he simply ignored the third wire, and luckily the Clip+ didn’t seem to complain and started up as expected.
[Conno] says there’s some careful flexing required to get the new pack installed and the Clip+ closed properly, and the device’s runtime is somewhat diminished by the new battery’s lower capacity. But if it means another few years of keeping Big Brother out of your digital media habits, he figures it’s a worthy trade.
The HTC Vive’s Lighthouse localization system is one of the cleverest things we’ve seen in a while. It uses a synchronization flash followed by a swept beam to tell any device that can see the lights exactly where it is in space. Of course, the device has to understand the signals to figure it out.
[Alex Shtuchkin] built a very well documented device that can use these signals to localize itself in your room. For now, the Lighthouse stations are still fairly expensive, but the per-device hardware requirements are quite reasonable. [Alex] has the costs down around ten dollars plus the cost of a microcontroller if your project doesn’t already include one. Indeed, his proof-of-concept is basically a breadboard, three photodiodes, op-amps, and some code.
His demo is awesome! Check it out in the video below. He uses it to teach a quadcopter to land itself back on a charging platform, and it’s able to get there with what looks like a few centimeters of play in any direction — more than good enough to land in the 3D-printed plastic landing thingy. That fixture has a rotating drum that swaps out the battery automatically, readying the drone for another flight.
If this is just the tip of the iceberg of upcoming Lighthouse hacks, we can’t wait!