Ask Hackaday: Calling All 68k Experts

This is a tale of old CPUs, intensive SMD rework, and things that should work but don’t.

Released in 1994, Apple’s Powerbook 500 series of laptop computers were the top of the line. They had built-in Ethernet, a trackpad instead of a trackball, stereo sound, and a full-size keyboard. This was one of the first laptops that looked like a modern laptop.

The CPU inside these laptops — save for the high-end Japan-only Powerbook 550c — was the 68LC040. The ‘LC‘ designation inside the part name says this CPU doesn’t have a floating point unit. A few months ago, [quarterturn] was looking for a project and decided replacing the CPU would be a valuable learning experience. He pulled the CPU card from the laptop, got out some ChipQuick, and reworked a 180-pin QFP package. This did not go well. The replacement CPU was sourced from China, and even though the number lasered onto the new CPU read 68040 and not 68LC040, this laptop was still without a floating point unit. Still, it’s an impressive display of rework ability, and generated a factlet for the marginalia of the history of consumer electronics.

Faced with a laptop that was effectively unchanged after an immense amount of very, very fine soldering, [quarterturn] had two choices. He could put the Powerbook back in the parts bin, or he could source a 68040 CPU with an FPU. He chose the latter. The new chip is a Freescale MC68040FE33A. Assured by an NXP support rep this CPU did in fact have a floating point unit, [quarterturn] checked the Mac’s System Information. No FPU was listed. He installed NetBSD. There was no FPU installed. This is weird, shouldn’t happen, and now [quarterturn] is at the limits of knowledge concerning the Powerbook 500 architecture. Thus, Ask Hackaday: why doesn’t this FPU work?

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Garage-built Aluminum Miniboat Tears Up The Surf. Or Not.

It’s the water-borne equivalent of building a minibike out of steel pipe and an old lawnmower engine. Except it’s a DIY personal watercraft made out of aluminum and an old chainsaw, and it has that same garage build feel – and the same disappointing results.

When we first saw the video below, we were hoping for one of those boats that let you water ski by yourself, or a wave-hopping, rooster tailing DIY jet ski. Alas, the chainsaw [MakeItExtreme] chose to power this boat is woefully underpowered, and the boat barely has enough oomph to make a wake. [MakeItExtreme] acknowledges the underwhelming results and mentions plans to fix the boat with a more powerful engine and a water jet drive rather than the trolling motor propeller they used. Still, whatever improvements they make will probably leverage the work they put into the hull, which is a pretty impressive display of metalwork. We’re used to seeing [MakeItExtreme] work in steel, so it was interesting to watch aluminum panels being cut, bent, and welded into a watertight hull. Looks like there’s plenty of room in there for more power, and we’re looking forward to version 2.0 of this build.

If you like rough and ready metalworking videos, there are plenty of them on [MakeItExtreme]’s YouTube channel. We’ve covered quite a few before, including this all-terrain hoverboard and a spot welder that’s more-or-less safe to use.

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You’re Overdue For A Visit To The Library

When was the last time you went to a library? If it’s been more than a couple of years, the library is probably a very different place than you remember. Public libraries pride themselves on keeping up with changing technology, especially technology that benefits the communities they serve. No matter your age or your interests, libraries are a great resource for learning new skills, doing research, or getting help with just about any task. After all, library science is about gathering together all of human knowledge and indexing it for easy lookup.

It doesn’t matter if you’re not a researcher or a student. Libraries exist to serve everyone in a class-free environment. In recent years, patrons have started looking to libraries to get their piece of the burgeoning DIY culture. They want to learn to make their lives better. Public libraries have stepped up to meet this need by adding new materials to their collections, building makerspaces, and starting tool libraries. And this is in addition to ever-growing collections of electronic resources. Somehow, they manage to do all of this with increasingly strained budgets.

The purpose of this article is to explore the ways that libraries of all stripes can be a valuable resource to our readers. From the public library system to the sprawling academic libraries on college campuses, there is something for hackers and makers at all levels.

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Modified R/C Jet Cannon Spews Nerf, Slays Cardboard Tanks

[ajw61185] made a video overview of a radio-controlled A-10 jet modified to spew a hail of harmless Nerf balls as it strafes helpless cardboard cutouts of T-72 tanks on a bright, sunny day.

A10 Nerf LoadingThe firing assembly in the jet comes from a Nerf Rival Zeus Blaster, which is itself an interesting device. It uses two electric flywheels to launch soft foam balls – much like a pitching machine. With one flywheel running a little faster than the other, the trajectory can be modified. For example, a slight topspin gives the balls a longer and more stable flight path. Of course, foam balls slow down quickly once launched and at high speeds the aircraft can overtake the same projectiles it just fired, but it’s fun all the same.

Cramming the firing assembly into aircraft took some cleverness. The front of the jet contains the flywheel assembly, and a stripped-down removable magazine containing the foam balls fits behind it. A flick of a switch on the controller spins up the flywheels, and another flick controls a servo that allows the balls to enter the firing assembly and get launched. The ammo capacity on the jet is low at only twelve shots per load, and it fires all twelve in roughly half a second. Since the balls are fired at the ground in a known area, they’re easy to retrieve.

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IKEA Lantern Houses Full-Featured Weather Station

From plain and utilitarian to the sleek and professional, there are a lot of ways to build a multifunction weather station. We’d thought we’d seen it all here, but building a weather station into an IKEA lantern is a pretty unique presentation.

There’s  an active community over at ikeahackers.net, and the variety of IKEA hacks they’ve come up with is pretty astounding. For this weather hack, [Richard Stevens] chose the Borrby, a $15 candle lantern. While it doesn’t exactly scream “weather station”, the form factor makes sense – plenty of room for electronics, easily replaced windows, and a nice cupola for mounting extra displays. [Richard]’s build includes a barometer, a hygrometer, and a thermometer, along with graphing displays for trends and historical data. There’s also an alarm clock and a rear panel bristling with more connectors and switches than an 80s-era HP oscilloscope. The wiring is admittedly “rats-nest style”, but as you can see in the video after the break, it works pretty well and looks good too.

Interested in rolling your own non-lantern weather station? Check out this headless Weather Underground sensor suite, or a simple panel of analog meters.

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Hackaday Prize Entry: A Charlieplexed Wristwatch

If there’s one thing we like, it’s blinky stuff, and you’re not going to get anything cooler than a display made of tiny SMD LEDs. That’s the idea behind this wristwatch and Hackaday Prize entry. It’s a tiny board, loaded up with an ATmega, a few buttons, and a bunch of LEDs in a big charlieplexed array.

The big feature of this display is the array of LEDs. This is a 16×5 array of 0603 LEDs packed together as tightly as possible. That’s a tiny, high-resolution LED display, but even with the ATmega88 microcontroller powering this board, all the LEDs are individually addressable, and a proper font for displaying the time, or anything else, is already mapped out.

LED matrices are pretty common around these parts, but building a custom display out of SMD LEDs is another level entirely. The best one we’ve seen was this unofficial badge from two DEF CONs ago. That was done the cheater’s way with a bunch of serially addressable LED drivers. This charlieplexed version goes above and beyond, and we’re eagerly awaiting the board files so this display can be replicated easily.

Multi Sensor Security Camera Has You Covered

Security in the home — especially a new home — is a primary concern for many. There are many options for security systems on the market, but for those will the skills, taking matters into your own hands can add peace of mind when protected by a system of one’s own design. [Armagan C.] has created  their near-ideal multi-sensor security module to keep a watchful eye out for would-be burglars.

Upgrading from their previous Arduino + Ethernet camera — which loved to trigger false alarms — [Armagan] opted for a used Raspberry Pi model B+ camera module and WiFi connection this time around. They also upgraded the unit with a thermal sensor, LPG & CO2 gas sensor, and a motion tracking alarm. [Armagan] has also set up a live streaming  feature that records video in 1hr segments — deleting them daily — and circumvented an issue with file descriptor leak by using a crashed drone’s flight controller to route the sensor data via serial port. It is also proving superior to conventional alarms because the custom software negates the need to disarm security zones during midnight trips to the washroom.

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