Tag Archives: MCU

Build a CNC Panel Cutter Controller

Posted on by

Want a CNC panel cutter and controller for your lab, hackspace, or workspace? James Koehler of Canada built an NXP Semiconductors mbed-based system to control a three-axis milling machine, which he uses to cut panels for electronic equipment. You can customize one yourself.

Panel Cutter Controller (Source: James Koehler)

According to Koehler:

Modern electronic equipment often requires front panels with large cut-outs for LCD’s, for meters and, in general, openings more complicated than can be made with a drill. It is tedious to do this by hand and difficult to achieve a nice finished appearance. This controller allows it to be done simply, quickly and to be replicated exactly.

Koehler’s design is an interesting alternative to a PC program. The self-contained controller enables him to run a milling machine either manually or automatically (following a script) without having to clutter his workspace with a PC. It’s both effective and space-saving!

The Controller Setup (Source: James Koehler)

How does it work? The design controls three stepping motors.

The Complete System (Source: James Koehler)

Inside the controller are a power supply and a PCB, which carries the NXP mbed module plus the necessary interface circuitry and a socket for an SD card.

The Controller (Source: James Koehler)

Koehler explains:

In use, a piece of material for the panel is clamped onto the milling machine table and the cutting tool is moved to a starting position using the rotary encoders. Then the controller is switched to its ‘automatic’ mode and a script on the SD card is then followed to cut the panel. A very simple ‘language’ is used for the script; to go to any particular (x, y) position, to lift the cutting tool, to lower the cutting tool, to cut a rectangle of any dimension and to cut a circle of any dimension, etc. More complex instructions sequences such as those needed to cut the rectangular opening plus four mounting holes for a LCD are just combinations, called macros, of those simple instructions; every new device (meter mounting holes, LCD mounts, etc.) will have its own macro. The complete script for a particular panel can be any combination of simple commands plus macros. The milling machine, a Taig ‘micro mill’, with stepping motors is shown in Figure 2. In its ‘manual’ mode, the system can be used as a conventional three axis mill controlled via the rotary encoders. The absolute position of the cutting tool is displayed in units of either inches, mm or thousandths of an inch.

Click here to read Koehler’s project abstract. Click here to read his complete documentation PDF, which includes block diagrams, schematics, and more.

This project won Third Place in the 2010 NXP mbed Design Challenge and is posted as per the terms of the Challenge.

 

 

Issue 261: Renesas RL78, Cap Touch, Synapse SNAP, & More!

Posted on by

Here’s a sneak peek at the projects and topics slated for the April issue of Circuit Cellar: Linux software development tools, DIY cap-touch, gain-controlled amplifier; color classification reader; start designing with the Renesas RL78 microcontroller; an introduction to sigma-delta modulators; RFI bypassing, with a focus on parallel capacitors; mesh networking simplified with SNAP technology; and more.

 

Clemens Valens introduces the Renesas Electronics RL78:

Click the image to link to the Renesas product page

Jeff Bachiochi takes a close look at Synapse Wireless SNAP technology:

Click the image to link to the Synapse-Wireless Kit webpage

Ed Nisley presents Part 2 of his article series “RFI Bypassing”:

The tracking generator output and spectrum analyzer input connect to adjacent PCB pads on the left of the SMD capacitor. Connecting the spectrum analyzer to the pad on the right side changes the measured self-resonant frequency.

The April issue will hit newsstands in late March.

Raspberry Pi: Is It for You?

Posted on by

Unless you’ve been locked in your lab or design studio for the past several weeks, you’ve likely heard about Raspberry Pi, which is a compact, affordable computer that has been creating a buzz on the ‘Net for some time now. The group behind the computer is the Raspberry Pi Foundation, which is a UK-based charity that has an ever-growing following of more than 52,000 followers on Twitter!

(Source: TechTheFuture.com and The Raspberry Pi Foundation)

According to the Raspberry Pi Foundation, “The Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. It’s a capable little PC which can be used for many of the things that your desktop PC does, like spreadsheets, word-processing and games. It also plays high-definition video. We want to see it being used by kids all over the world to learn programming.”

The 85.60 mm × 53.98 mm × 17 mm Raspberry Pi weighs in at 45 g. It features a Broadcom BCM2835, including an ARM1176JZFS and a Videocore 4 GPU.

So, how can Circuit Cellar members use Raspberry Pi? Well, look at it in three ways. One, you can use it in a design of your own. Grab one and start building as soon as you can get your hands on one. Two, you can learn from the “story” of the Raspberry Pi Foundation—how it formed, how it works as a charity—and consider launching a tech foundation of your own. Three, you can design a low-cost embedded design platform or rapid prototyping solution—something distinguishable from the usual suspects of Arduino and mbed—and bring it to market.

In a recent post titled “What Are You Doing!?” at TechTheFuture.com, Tessel Renzenbrink detailed an interview with Eben Upton, a founder and trustee of the Raspberry Pi Foundation. Tessel writes:

Raspberry Pi is grabbing the attention with a $25 computer ($35 for a networked model). In the middle of the storm is Eben Upton. Why is he convinced that a computer which has no casing, no keyboard, no HD and no screen, will be successful? It is time to put the question to him: ‘what are you doing?’

‘We wanted to have a computer especially for Python, and there is a great tradition of naming computers after fruit: like Apricot, Acorn and even today there are computers named after fruit. So Raspberry is following the line of a rich tradition with the Pi, and yes, we wanted this connection with Python. That is where the Pi comes in’, explains Eben when asked for the name Raspberry Pi. And why is it a charity that brings this computer to the market? ‘That all has to do with value creation’, Eben continues. ‘I’ve been involved in several start-ups and then you always end up with the question; how will this create value?’. ‘In this case I do not have to worry about creating value. I can concentrate on designing and producing the board. The Raspberry Pi can be seen as a ‘white label’ product. If there are people out there with a commercial idea for this product, they are more then welcome’.

The Raspberry Pi is a bare PCB board; no keyboard, no HD, no screen.. how will this product become successful? ‘Basically, there is no reason why a computer has to cost more than $50. The peripherals like a screen and keyboard and storage will create a higher price, but with the Raspberry Pi we have taken another route – a normal TV can be used as a screen’, comments Eben. ‘Combine that with a ‘charity shop’ keyboard for a few dollars and you have a full working system’. He further emphazises that ‘the Raspberry is specifically aiming at youngsters learning to program’.

And how about the Raspberry Pi being ‘the next big thing’ after Arduino? There are many hints in that direction on the Internet? ‘The Raspberry Pi is different from the Arduino. The Arduino is great for direct applications and there are dozens of programs available. The Raspberry Pi is a computer system – designed to work with a screen and keyboard, a completely different idea. You can even watch videos with this thing. What might be interesting is the possibility to use the Raspberry Pi as a host for the Arduino board – the combination of these two, resulting in low priced systems can be very interesting and useful’.

‘There is also a difference the flexibility and usability, adds Eben. We have chosen for Broadcom chips and they are not easy to get in the market, making it very difficult to call the Raspberry Pi an ‘open source’ project. We are hoping to take this development into the open source direction, but that will require a new design’.

Can designers use the Raspberry Pi for different applications? ‘Yes, no problem. There is plenty of I/O (I2C and UART) to start using it for whatever challenges you’.

The first batch of 10,000 Pi’s has now arrived from the factory – what will be the next step? ‘Another 10,000 we hope and that is all just the start of it…’

You can read the entire post at TechTheFuture.com.

If you want to check out other kits and modules, visit the CC Webshop.

TechTheFuture.com is part of the Elektor group.

 

Weekly Elektor Wrap Up: Laser, Digital Peak Level Meter, & “Wolverine” MCU

Posted on by

It’s Friday, so it’s time for a review of Elektor news and content. Among the numerous interesting things Elektor covered this week were a laser project, a digital peak level meter for audio engineering enthusiasts, and an exciting new ultra-low-power MCU.

Are you an embedded designer who wants to start a laser project? Read about “the world’s smallest laser”:

What is the biggest constraint in creating tiny lasers? Pump power. Yes sir, all lasers require a certain amount of pump power from an outside source to begin emitting a coherent beam of light and the smaller a laser is, the greater the pump power needed to reach this state. The laser cavity consists of a tiny metal rod enclosed by a ring of metal-coated, quantum wells of semiconductor material. A team of researchers from the University of California has developed a technique that uses quantum electrodynamic effects in coaxial nanocavities to lower the amount of pump power needed. This allowed them to build the world’s smallest room-temperature, continuous wave laser. The whole device is only half a micron in diameter (human hair has on average a thickness of 50 micron).

The nanolaser design appears to be scalable – meaning that they could be shrunk to even smaller sizes – an important feature that would make it possible to harvest laser light from even smaller structures. Applications for such lasers could include tiny biochemical sensors or high-resolution displays, but the researchers are still working out the theory behind how these tiny lasers operate. They would also like to find a way to pump the lasers electrically instead of optically.

Be sure to check out Elektor’s laser projection project.

In other news, Elektor reached out to audio engineering-minded audio enthusiasts and presented an interesting project:

Are you an audio amateur hobbyist or professional? Do you try to avoid clipping in your recordings? To help you get your audio levels right, in January 2012 Elektor published a professional-quality peak level meter featuring 2x 40 LEDs, controlled by a powerful digital signal processor (DSP). As part of the eight-lesson course on Audio DSP, all the theory behind the meter was explained, and the accompanying source code was made available as a free download.

The DSP Board has been available for a while, and now we are proud to announce that the Digital Peak Level Meter is available as an Elektor quality kit for you to build. Although the meter was designed as an extension module for the Audio DSP board, it can be used with any microcontroller capable of providing SPI-compatible signals. So get your Peak Level Meter now and add a professional touch to your recording studio!

And lastly, on the MCU front, Elektor ran interesting piece about the Texas Instruments “Wolverine,” which should be available for sampling in June 2012:

Codenamed “Wolverine” for its aggressive power-saving technology, the improved ultra-low-power MSP430 microcontroller platform from Texas Instruments offers at least 50 % less power consumption than any other microcontroller in the industry: 360 nA real-time clock mode and less than 100 µA/MHz active power consumption. Typical battery powered applications spend as much as 99.9 % of their time in standby mode; Wolverine-based devices can consume as little as 360 nA in standby mode, more than doubling battery life.

Wolverine’s low power performance is made possible by using one unified ferromagnetic RAM (FRAM) for code and data instead of traditional Flash and SRAM memories, allowing them to consume 250 times less energy per bit compared to Flash- and EEPROM-based microcontrollers. Power consumption is further reduced thanks to an ultra low leakage  process technology that offers a 10x improvement in leakage and optimized mixed signal capabilities.

MSP430FR58xx microcontrollers based on the Wolverine technology platform will be available for sampling in June 2012.

Circuit Cellar and CircuitCellar.com are part of the Elektor group.

 

DIY Cap-Touch Amp for Mobile Audio

Posted on by

Why buy an amp for your iPod or MP3 player when you can build your own? With the proper parts and a proven plan of action, you can craft a custom personal audio amp to suit your needs. Plus, hitting the workbench with some chips and PCB is much more exciting than ordering an amp online.

In the April 2012 issue of Circuit Cellar, Coleton Denninger and Jeremy Lichtenfeld write about a capacitive-touch, gain-controlled amplifier while studying at Camosun College in Canada. The design features a Cypress Semiconductor CY8C29466-24PXI PSoC, a Microchip Technology mTouch microcontroller, and a Texas Instruments TPA1517.

Denninger and Lichtenfeld write:

Since every kid and his dog owns an iPod, an MP3 player, or some other type of personal audio device, it made sense to build a personal audio amplifier (see Photo 1). The tough choices were how we were going to make it stand out enough to attract kids who already own high-end electronics and how we were going to do it with a budget of around $40…

The capacitive-touch stage of the personal audio amp (Source: C. Denninger & J. Lichtenfeld)

Our first concern was how we were going to mix and amplify the low-power audio input signals from iPods, microphones, and electric guitars. We decided to have a couple of different inputs, and we wanted stereo and mono outputs. After doing some extensive research, we chose to use the Cypress Semiconductors CY8C29466-24PXI programmable system-on-chip (PSoC). This enabled us to digitally mix and vary the low-power amplification using the programmable gain amplifiers and switched capacitor blocks. It also came in a convenient 28-pin DIP package that followed our design guidelines. Not only was it perfect for our design, but the product and developer online support forums for all of Cypress’s products were very helpful.
Let’s face it: mechanical switches and pots are fast becoming obsolete in the world of consumer electronics (not to mention costly when compared to other alternatives). This is why we decided to use capacitive-touch sensing to control the low-power gain. Why turn a potentiometer or push a switch when your finger comes pre-equipped with conductive electrolytes? We accomplished this capacitive touch using Microchip Technology’s mTouch Sensing Solutions series of 8-bit microcontrollers. …

 

The audio mixer flowchart

Who doesn’t like a little bit of a light show? We used the same aforementioned PIC, but implemented it as a voltage unit meter. This meter averaged out our output signal level and indicated via LEDs the peaks in the music played. Essentially, while you listen to your favorite beats, the amplifier will beat with you! …
This amp needed to have a bit of kick when it came to the output. We’re not talking about eardrum-bursting power, but we wanted to have decent quality with enough power to fill an average-sized room with sound. We decided to go with a Class AB audio amplifier—the TPA1517 from Texas Instruments (TI) to be exact. The TPA1517 is a stereo audio-power amplifier that contains two identical amplifiers capable of delivering 6 W per channel of continuous average power into a 4-Ω load. This quality chip is easy to implement. And at only a couple of bucks, it’s an affordable choice!

 

The power amplification stage of the personal audio amp (Souce: C. Denninger & J. Lichtenfeld)

The complete article—with a schematic, diagrams, and code—will appear in Circuit Cellar 261 (April 2012).