More WiFi Modules for IoT Madness

IoT

The last year has brought us CC3000 WiFi module from TI, and recently the improved CC3200 that includes an integrated microcontroller. The Chinese design houses have gotten the hint, putting out the exceptionally cheap ESP8266, a serial to WiFi bridge that also includes a microcontroller to handle the TCP/IP stack and the software side of an 802.11 connection. Now there’s another dedicated WiFi module. It’s called the MT7681, and it’s exactly what you would expect given the competition: a programmable module with the ability to connect to a WiFi network.

Like TI’s CC3200, and the ESP8266, the MT7681 can be connected to any microcontroller over a serial connection, making it a serial to WiFi bridge. This module also contains a user-programmable microcontroller, meaning you don’t need to connect an Arduino to blink a few pins; UART, SPI, and a few GPIO pins are right on the board. The module also includes an SDK and gnu compiler, so development of custom code running on this module should be easier than some of the other alternatives.

You can pick up one of the MT7681 modules through the usual channels, but there’s an Indiegogo campaign based in China that takes this module and builds a ‘dock’ around it. The dock has a relay, temperature/humidity sensor, a few GPIO pins, and a USB serial connection for use as an Internet of Things base station.

For anyone looking for a little more computational horsepower, there’s also a few mentions and press releases announcing another module, the MT7688, This is a very small (12mm by 12mm) module running Linux with 256 MB of RAM and 802.11n support. This module hasn’t even hit the market yet, but we’ll be on the lookout for when it will be released.

Thanks [uhrheber] for sending this one in.

The Current State of ESP8266 Development

ESP A few weeks ago we caught wind of a very cool new chip. It’s called the ESP8266, and it’s a WiFi module that allows you to connect just about any project to an 802.11 b/g/n network. It also costs $5. Yes, there was much rejoicing when this chip was announced.

Since we learned of the ESP8266, there has been a lot of work done to translate the datasheets from Chinese, figure out how the SOC can be programmed, and a few preliminary attempts at getting this module working with an Arduino. Keep in mind, very few people have one of these modules in hand right now, so all this information is completely untested. Here’s what we have so far:

Over on Hackaday Projects, [bafeigum] has been working to research the capabilities of this module. Most of the comments deal with the AT Command set for the module and figuring out what is actually returned when certain commands are called.

The ESP8266 community forum is about a week old, but already there’s a wealth of information. Most of the efforts seem to be centered on getting GCC to program this chip, something that would make the ESP8266 a single-solution chip for anything that needs WiFi and a bit of processing power. Everyone (including the great [Sprite_TM]) has currently hit a roadblock, so if you have a ton of experience with GCC and the Xtensa microcontroller, check out that thread. Failing that, we’ll have to wait until someone from Tensilica, the company behind the guts of this chip, to chime in and help everyone figure out how this thing actually works.

The Arduino-heads out there will have a much easier time. There’s already a tutorial for using the ESP8266 as a serial WiFi module. Note the ESP operates on 3.3 Volts, so connecting this module to the 5V pin means you’ll be out $5 and several weeks of shipping time.

This is an incredible amount of development in a very short amount of time, made even more remarkable by the fact that no one has one of these WiFi modules yet. When these modules do arrive to workbenches around the world, we’ll expect the Hackaday tip line to be flooded with very small and somewhat battery friendly WiFi builds.

Electric Chainsaw Teardown

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

Dorkbot logo on a large LCD display

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.

LEGO® My Single-Phase Induction Motor

[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

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

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.

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