Turn Cordless Tool Batteries into USB Chargers

It is the unspoken law of cordless tools – eventually you will have extra batteries lying around from dead tools that are incompatible with your new ones. Some people let them sit in lonesome corners of the garage or basement; others recycle them. [Eggmont] was facing this dilemma with a Makita battery from a broken angle grinder and decided to make a USB charger out of it.

[Eggmont] took the simplistic approach, using an old cigarette lighter-to-USB adapter. First, [Eggmont] removed the battery connector from the bottom of the broken angle grinder. Next, the casing surrounding the cigarette lighter plug was removed so that the adapter’s wires could be soldered to the contacts on the battery connector.  The USB ports were then glued onto the top of the connector. The adapter was rated 9-24V input, so it was fine to use it with the 18V tool battery. Since the battery connector is still removable, the battery can be recharged.

Tool manufacturers are tapping into the market of repurposing old batteries for charging mobile devices. Both DeWalt and Milwaukee Tool have now created their own USB adapters that connect to their batteries. Or, you can purchase the Kickstarter-funded PoweriSite adapter for DeWalt batteries instead. Compared to their cost, [Eggmont’s] project is very economical if you already have the battery at hand – you can find the USB adapter for less than $10 on Amazon.

Adding a Steady Rest to a Lathe

A steady rest is a tool for a lathe, enabling a machinist to make deep cuts in long, slender stock, bore out thin pieces of metal, and generally keeps thin stuff straight. Unlike a tool that follows the cutter, a steady rest is firmly attached to the bed of a lathe. [Josh]’s lathe didn’t come with a steady rest, and he can’t just get parts for it. No problem, then: he already has a lathe, mill, and some metal, so why not make the base for one from scratch?

[Josh] was able to find the actual steady rest from an online dealer, but it wasn’t made for his lathe. This presented a problem when attaching it to his machine: because each steady rest must fit into the bed of the lathe, he would need a custom bracket. With the help of a rather large mill, [Josh] faced off all the sides of a piece of steel and cut a 45 degree groove. To make this base level, [Josh] put one side of the base on the lathe, put a dial micrometer on the tool post, and got an accurate reading of how much metal to take off the uncut side.

With the steady rest bolted onto the lathe, [Josh] turned a rod and found he was off by about 0.002″. To machinists, that’s not great, but for a quick project it’s fantastic. Either way, [Josh] really needed a steady rest, and if it works, you really can’t complain.

Continue reading “Adding a Steady Rest to a Lathe”

Improving the T-962 Reflow Oven

The T-962A is a very popular reflow oven available through the usual kinda-shady retail channels. It’s pretty cheap, and therefore popular, and the construction actually isn’t abysmal. The controller for this oven is downright terrible, and [wj] has been working on a replacement firmware for the horribly broken one provided with this oven. It’s open source, and the only thing you need to update your oven is a TTL/UART interface.

[WJ] bought his T-962A even after seeing some of the negative reviews that suggested replacing the existing controller and display. This is not in true hacker fashion – there’s already a microcontroller and display on the board.

The new firmware uses the existing hardware and adds a very necessary modification: stock, the oven makes the assumption that the cold-junction of the thermocouples is at 20°C. The controller sits on top of an oven with two TRIACs nearby, so this isn’t the case, making the temperature calibration of the oven slightly terrible.

After poking around the board, [WJ] found an LPC2000-series microcontroller and a spare GPIO pin for a 1-wire temperature sensor. The temperature sensor is placed right next to the terminal block for the thermocouples for proper temperature sensing.

All the details of updating the firmware appear on a wiki, and the only thing required to update the firmware is a serial/USB/UART converter. A much better solution than ripping out the controller and replacing it with a custom one.

Easy and Effective Way to Measure PWM… Without a Scope!

Sometimes when a project is coming together, you need to cobble a tool together to get it completed. Whether it’s something very involved, like building a 3D printer to fabricate custom parts, or something relatively simple, like wiring a lightbulb and a battery together to create a simple continuity checker, we’ve all had to come up with something on the fly. Despite having access to an oscilloscope, [Brian] aka [schoolie] has come up with his own method for measuring PWM period and duty cycle without a scope, just in case there’s ever a PWM emergency!

The system he has come up with is so simple it’s borderline genius. The PWM signal in question is fed through a piezo speaker in parallel with a resistor. The output from the speaker is then sent to an FFT (fast fourier transform) app for Android devices, which produces a picture of a waveform. [schoolie] then opens the picture in MS Paint and uses the coordinates of the cursor and a little arithmetic to compute the period and the duty cycle.

For not using a scope, this method is pretty accurate, and only uses two discrete circuit components (the resistor and the speaker). If you’re ever in a pinch with PWM, this is sure to help, and be a whole lot cheaper than finding an oscilloscope!

Serial Surgery Saves Wacom Tablet from Landfill

Years ago, [Greg] got a Wacom Artpad II graphics tablet through Freecycle. What’s the catch, you ask? The stylus was long gone. When he found out how expensive a direct replacement would be, the tablet was laid to rest in his spare parts box. Fast forward a few years to the era of the phone-tablet hybrid and [Greg]’s subsequent realization that some of them use Wacom stylii. Eight bucks later, he’s in business, except that the tablet is serial. Wacom no longer supports serial tablets, so he had to convert it to USB.

With the help of the WaxBee project and a Teensy 2.0, he would be able to emulate an Intuous2 tablet by sniffing and re-encoding the packets.  Things got a little hairy when he went under the hood to remove the ADM202 TTL-to-RS232 chip with a Dremel—he accidentally gouged some of the pads it sat on as well as a few of the traces. Feeling frustrated, [Greg] took some high-res pictures of the board and posted them to a message board. As it turns out, those pictures helped him recreate the traces and get the tablet running. A little big of glue and tape later, he was in business. [Greg] even gave himself access to reprogram the Teensy.

Creating a Scanning Monochromator

If you need a specific wavelength of light for research purposes, the naïve way of obtaining that is a white source light, a prism, and a small slit that will move across your own personal Dark Side of the Moon album cover. This is actually a terrible idea; not only won’t you have a reference of exactly what wavelength of light you’re letting through the optical slit, the prism itself will absorb more of one wavelength of light than others.

The solution is a monochromator, a device that performs the same feat of research without all the drawbacks. [Shahriar] got his hands on an old manual monochromator and decided to turn it into a device that performs automatic scans.

The key of a monochromator is a diffraction grating, a mirrored surface with many fine parallel grooves arranged in a step pattern. Because of the surface of the diffraction grating, it’s possible to separate light according to its spectrum much like a prism. Unlike a prism, it’s effectively a first surface mirror meaning all wavelengths of light are reflected more or less equally.

By adding a stepper motor to the dial of his monochromator, [Shahriar] was able to automatically scan across the entire range of the device. Inside the monochromator is a photomultiplier tube that samples the incoming light and turns it into a voltage. By sampling this voltage and plotting it with MATLAB, [Shahriar] was able to plot the intensity of every wavelength of light within the range of the device. It’s all expertly explained in the video below.

Continue reading “Creating a Scanning Monochromator”

A Modern Woodworking Workbench

This is a post about workbenches, but not the benches you’re probably thinking about. Workbenches meant for electronics development are simple matters – just about any flat surface, a few shelves for equipment, and an anti-static mat will be fine for every conceivable use.  Workbenches for woodworking are a separate matter entirely. There’s actually quite a bit of history behind the development of the woodworking workbench, but the basic idea is a thick laminated wood top, integrated vices, holes in the work surface for bench dogs, and ergonomics that allow for comfortable use of hand tools. The basic design of these benches hasn’t changed much in several hundred years, and [Dirk] thought the design was ready for a modern update.

Continue reading “A Modern Woodworking Workbench”