That irresistible urge to rescue an interesting piece of hardware from the trash is something that pretty much every Hackaday reader will have felt at one time or another. Sometimes it’s something that you could put to work immediately, like an old computer or some scrap piece of material that’s just the right size. But other times, you find something on the side of the road that ends up being the impetus for a whole new project.
For [David Bertet], finding a beat up kid’s Jeep Wrangler on the curb was the first step towards a journey that ends with PowerJeep: an open source project that we wager could end up saving similar vehicles from the landfill. The basic idea is simple enough — strip out the vehicle’s original 12 volt power supply and replace it with 18 V provided by easily swappable tool batteries. But as is often the case, it’s the details and the documentation that sets this project apart.
In an ideal world, every single battery pack for power tools would use the same physical interface and speak a clearly documented protocol with chargers. Since we live in a decidedly less-than-ideal world, we get to enjoy the fun pastime of reverse-engineering the interfaces and protocols of said battery packs.
Hooking up a logic analyzer to a M18 battery and charger.
A recent video from the [Tool Scientist] goes over what is already known about the Milwaukee M18 Redlink protocol, used with the manufacturer’s M18-series of batteries, before diving into some prodding and poking of these packs’ sensitive parts to see what comes out of their interface.
Previously, [Buy It Fix It] shared their findings on Reddit, covering the basic protocol, including the checksum method, but without an in-depth analysis of the entire charging protocol. Meanwhile [Quagmire Repair] performed an in-depth teardown and reverse-engineering of the M18 hardware, including the circuitry of the BMS.
Putting these two things together, [Tool Scientist] was able to quickly get some of his M18 packs strapped down into the analysis chair for both passive analysis, as well as the effect of overvoltage, undervoltage, overheating and freezing the battery pack on the output reported by the battery’s BMS.
One of the lists of commands and response messages obtained by [Tool Scientist] on YouTube.The result is a rather comprehensive list of instructions obtained under these various conditions, including a fault condition (05) returned by the BMS of one pack indicating its likely demise. Overall, it does not appear to be a particularly special (or well-designed) protocol, but it does make for a good reverse-engineering target, while adding to the body of collective knowledge on these widely available battery packs.
Hopefully the same inertia that prevents people from moving outside the designated power tool ecosystem due to the incompatible battery packs will also ensure that this level of knowledge will remain relevant for the foreseeable future, especially since the manufacturers of knock-off battery packs seem rather unwilling to share the results of their own reverse-engineering efforts.
A solder fume extractor is something we could probably all use. While there isn’t much to them, [Steven Bennett] put a lot of thought into making one that was better for him, and we admired his design process, as well as the extractor fan itself. You can see the finished result in the video below.
The electrical design, of course, is trivial. A computer fan, a switch, and a battery — in this case, a Makita power tool battery. But the Fusion 360 design for the 3D printed parts got a lot of thought to make this one of the best fume extractor fans we’ve seen.
![One of the lists of commands and response messages obtained by [Tool Scientist] on YouTube.](https://hackaday.com/wp-content/uploads/2023/09/reverse_engineering_milwaukee_m18_redlink_protocol_startup_messages.jpg)
