Electric Chainsaw Teardown

June 24, 2014 by Eric Evenchick 67 Comments

An electric chainsaw with its case removed

For his Beyond Unboxing series, [Charles] tore apart a Ryobi cordless chainsaw to get a better look at how this battery powered tool works.

Inside he found a three-phase motor and controller. This motor looks like it could be useful in other projects since it has a standard shaft. The battery pack was popped open to reveal a set of LG Chem 21865 cells, and some management hardware.

With all the parts liberated from the original enclosure, [Charles] set up the motor, controller, and battery on the bench. With a scope connected, some characterization of the motor could be done. A load was applied by grabbing the spinning shaft with welding gloves. [Charles] admits that this isn’t the safest way to test a motor.

While it is a very fast motor, the cut-in speed was found to be rather low. That means it can’t start a vehicle from a stop, but could be useful on e-bikes or scooters which are push started.

This chainsaw a $200 motor, controller, and battery set that could be the basis of a DIY scooter. It sounds great too, as the video after the break demonstrates.

[Thanks to Dane for the tip!]

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Reverse Engineering LCD Displays

June 20, 2014 by Eric Evenchick 9 Comments

Over at DorkbotPDX in Portland, a member showed up with a stack of large LCD displays from point of sale terminals. [Paul] took it upon himself to reverse engineer the displays so that they can be recycled in future projects.

The control circuit for this LCD resides on a rather large PCB with quite a variety of components. The board was reduced to three main components: an MSM6255 display controller, a 32k RAM chip which is used as the framebuffer, and a tri-state driver.

With all the unneeded components out of the way, a custom board based around an ATmega88 MCU was added. This board was soldered in to interface with the LCD controller’s bus. This allows data to be written from the 128k flash ROM on the custom board into the frame buffer. Once this is done, the display controller will display the data on the LCD.

Now that data could be written, [Paul] figured out the correct configuration for the display controller. That was the final piece in getting images to show up correctly on the display. If you happen to find some old Micros 2700 POS terminals, [Paul]’s detailed write-up will help you scavenge the displays.

Designing And Printing A Custom Enclosure

June 5, 2014 by Brian Benchoff 19 Comments

enclosure

So you know how to design a circuit board, assemble the parts, and have a functional device at the end of a soldering session. Great, but if you want to use that device in the real world, you’re probably going to want an enclosure, and Tupperware hacked with an Exacto knife just won’t cut it. It’s actually not that hard to design a custom enclosure for you board, as [Glen] demonstrates with a custom 3D printed project box.

[Glen]’s board, a quad RS-422 transmitter with a PMOD connector, was designed in Eagle. There are a vast array of scripts and plugins for this kind of mechanical design work, including the EagleUP plugins that turn an Eagle PCB into a 3D object that can be imported into SketchUp.

Taking measurements from Eagle, [Glen] designed a small project box that fits the PCB. A few standoffs were added, and the board itself was imported into SketchUp. From there, all he needed to do was to subtract the outline of the connectors from the walls of then enclosure for a custom-fit case. Much better than Tupperware, and much easier than designing a laser cut enclosure.

Once the enclosure was complete, [Glen] exported the design as an STL, ready for 3D printing or in his case, sending off to Shapeways. Either way, the result is a custom enclosure with a perfect fit.

LEGO® My Single-Phase Induction Motor

March 30, 2014 by Kristina Panos 5 Comments

[Diato556] made a really cool single-phase induction motor with parts mounted on Duplo blocks. He has posted an Instructable where he uses these modular parts to demonstrate the motor and the principles of induction as described after the jump.

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The Beginnings Of An LCR Meter

March 15, 2014 by Nick Conn 12 Comments

LCR Meter

The inductor is an often forgotten passive electrical elements used to design analog circuitry. [Charles’s] latest proof of concept demonstrates how to measure inductance with an oscilloscope, with the hopes of making a PIC based LCR meter.

It is not that often one needs to measure inductance, but inductors are used in switching regulators, motor circuits, wireless designs, analog audio circuitry, and many other types of projects. The principles of measuring inductance can be used to test inductors that you have made yourself, and you can even use this knowledge to measure capacitance.

[Charles] originally saw a great guide on how to measure impedance by [Alan], and decided to run with the idea. Why spend over $200 on an LCR meter when you can just build one? That’s the spirit! Be sure to watch [Alan’s] and [Charles’s] videos after the break. What kind of test equipment have you built in order to save money?

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Direct, Wall-Mounted Storage With Lasers And Polymorph

December 24, 2013 by Marsh 14 Comments

parts-storage-brackets

We’re sure everyone could use some more storage and organization in their workshop. [Nixie] is no exception, though he also hates sacrificing tabletop space for boxes. His solution was to attach them to the wall directly by hacking together some brackets. This hack allowed him to hang everything without using internal screws which were a pain to get at if he need to removed the boxes from the wall to take with him.

[Nixie] started by laser-cutting a negative pattern for a mounting bracket that would fit the dovetail rails already on the sides of the boxes. He then pressed a piece of polymorph into this mold, slid the bracket along the side of the box…and realized it wouldn’t work. The piece wiggled around too much because it did not sit firmly in the rail. Back at the drawing board, [Nixie] split the project into two steps. He cast the screw-hole portion of the bracket in its own separate mold, then cast the railing part of the bracket directly in the dovetail section of the box, providing him a much higher degree of accuracy. After joining the two pieces, [Nixie] had a sturdy support bracket that he duplicated and attached around the rest of the bins.

FT230X Brings USB Charging Detection To The Serial IC Game

November 16, 2013 by Mike Szczys 4 Comments

FT230XS-breadboard

Here’s a new chip from FTDI which brings a nice little feature to the USB-to-serial converter family: charging detection. That means that it is capable of detecting when a battery charger is connected. What does that actually mean? The top of the datasheet gives you the short version, but let’s look at the investigation [Baoshi] undertook to test the full extent of this particular feature. We agree with him that the listed capability leaves those in the know with a lot of questions:

USB Battery Charger Detection. Allows for USB peripheral devices to detect the presence of a higher power source to enable improved charging.

Obviously the chip will be able to tell when a charger is connected, alerting the device when it’s time to start lapping up the extra milliamps. But what type of chargers will actually trigger the detection circuit? After rigging up the test circuit shown above he ran through several scenarios: connected directly to the PC USB port, via externally powered and non-powered USB hubs, and with multiple wall wart chargers. Full results of the tests are included in the post linked above.

[via Dangerous Prototypes]