Homebrew Phase Laser Rangefinder

laser

Just when you thought ARM micros couldn’t get any cooler, another project comes along to blow you away. [Ilia] created a phase laser rangefinder (.ru, Google translatitron) using nothing but a laser diode, a pair of magnifying glasses, a few components and an STM32F4 Discovery dev board.

The theory behind this build is using a laser’s phase to determine how far away an object is. By modulating the laser diode’s output at a few hundred Mhz, the reflection from the laser can be compared, giving a fairly reasonable estimate of how far away the target is. This method has a few drawbacks; once the reflection is more than 360 degrees out of phase, the distance ‘loops around’ to being right in front of the detector.

The laser diode used does not have any modulation, of course, but by using an STM32F4 ARM chip, [Ilia]was able to modulate the amplitude of the laser with the help of a driver board hacked out of a 74HC04 chip and a few resistors. Not ideal, but it works.

The receiver for the unit uses a photodiode feeding into the same microcontroller. With an impressive amount of DMA and PLL wizardry (the STM32F4 is really cool, you know), the phase of both the transmission and reflection can be compared, giving a distance measurement.

It’s all an impressive amount of work with a hacked together set of optics, a cheap dev board, and a few components just lying around. For any sort of application in a robot or sensor suite this project would fall apart. As a demonstration of the theory of phase laser rangefinding, though, its top notch.

You can check out a video of [Ilia]’s rangefinder below. Be sure to full screen it and check out the distance measurement on the LCD. It’s pretty impressive.

Thanks [Володимир] for the link.

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NXP’s ARM Micros With Motor Controllers

motor

It’s still relitavely early in the year, and all those silicon manufacturers are coming out with new toys to satiate the engineer and hobbyist for years to come. NXP’s offering is the LPC1500, a series of ARM microcontrollers optimized for motor and motion-control applications.

The specs for the new chips include an ARM Cortex-M3 running at 72MHz, up to 256kB Flash, 36kB SRAM, USB, CAN, 28 PWM outputs, an a real-time clock. There are options for controlling brushless, permanent magnet, or AC induction motors on the LPC1500, with dev boards for each type of motor. Each chip has support for two Despite NXP’s amazing commitment to DIP-packaged ARM chips, the LPC1500 chips are only available in QFP packages with 48, 64, and 100 pins.

Don’t think the LPC1500 would be a perfect chip for a CNC controller – the chips only support control of two motors. However, this would be a fantastic platform for building a few robots, an electric car, or a lot of the other really cool projects we see around here.

ARM Debugger for Nearly One Dollar

Oh that title is so misleading. But if you squint your eyes and scratch your noggin it’s almost true. Thanks to the hard work of [Peter Lawrence] it is now possible to hack together an extremely inexpensive CMSIS-DAP ARM debugger.

Let’s talk about function and we’ll get back to cost later. CMSIS-DAP is a standard that gives you the kind of breakpoint control you expect from a proper debugger. In this case [Peter] implemented the standard using 4k words of space on a PIC 16F1454. This lets it talk to the debug port on ARM chips, and the bootloader (also written by him) doubles as a USB-to-UART bridge. Boom, done. OpenOCD (and a couple of other software packages) talks to the PIC and it talks to the ARM. Nice.

Back to the cost question. You can get a 16F1454 for nearly a dollar when you order in quantity. If you cut up an old USB cable, recycle some jumper wire, and already have power and decoupling on hand, you’re in business for nearly one dollar.

Autonomous Quadcopter Fits in the Palm of your Hand

[Horiken Engineering], which is made up of engineering students at the department of aerospace at the University of Tokyo have developed an autonomous quadcopter that requires no external control — and its tiny. By using two cameras and a sonar sensor, the quadcopter is capable of flying by itself due to its ability to process the data from the on-board sensors. To do the complex data processing fast enough to fly, it is using a Cortex-M4 MCU, a Spartan-6 FPGA, and 64MBs of DDRSDRAM. It also has the normal parts of a quadcopter, plus gyros, a 3D printed frame and a 3-axis compass. The following video demonstrates the quadcopter’s tracking ability above a static image (or a way point). The data you see in real-time is only the flight log, as the quadcopter receives no signal — it can only transmit data.

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Making An ARM Powered MIDI Synthesizer

What you see in the picture above is a hand-made 4-oscillator synthesizer with MIDI input, multi-mode filter and a handful of modulation options. It was built by [Matt], an AVR accustomed electronics enthusiast who made an exception to his habits for this project. The core of the platform is a DIP packaged 32-bit Cortex-M0 ARM processor (LPC1114), stuffed with ‘hand’ written assembly code and compiled C functions. With a 50MHz clock speed, the microcontroller can output samples at 250kHz on the 12bit DAC while being powered by 3 AA batteries.

Reading [Matt]’s write-up, we discover that the firmware he created uses 4 oscillators (sawtooth or pulse shape) together with a low frequency oscillator (triangle, ramp, square, random shapes). It also includes a 2-pole state-variable filter and the ability to adjust the attack-release envelopes (among others). The system takes MIDI commands from a connected device. We embedded videos of his creation in action after the break.

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Meet the Teensy 3.1

[Paul Stoffregen] just released an updated version of his Teensy 3.0, meet the oddly named Teensy 3.1. For our readers that don’t recall, the Teensy 3.0 is a 32 bit ARM Cortex-M4 based development platform supported by the Arduino IDE (using the Teensyduino add-on). The newest version has the same size, shape & pinout, is compatible with code written for the Teensy 3.0 and provides several new features as well.

The Flash has doubled, the RAM has quadrupled (from 16K to 64K) allowing much more advanced applications. The Cortex-M4 core frequency is 72MHz (48MHz on the Teensy 3.0) and the digital inputs are 5V volts compatible. Pins 3 and 4 gained CAN bus functions. The new microcontroller used even has a 12 bits Digital to Analog Converter (DAC) so you could create a simple signal generator like the one shown in the picture above. Programming is done through the USB port, which can later behave as host or slave once your application is launched. Finally, the price tag ($19.80) is in our opinion very reasonable.

Embedded below is an interview with its creator [Paul Stroffregen].

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Interview with [Damien George], Creator of the Micro Python project

[Damien George] just created Micro Python (Kickstarter alert!), a lean and fast implementation of the Python scripting language that is optimized to run on a microcontroller. It includes a complete parser, compiler, virtual machine, runtime system, garbage collector and was written from scratch. Micro Python currently supports 32-bit ARM processors like the STM32F405 (168MHz Cortex-M4, 1MB flash, 192KB ram) shown in the picture above and will be open source once the already successful campaign finishes. Running your python program is as simple as copying your file to the platform (detected as a mass storage device) and rebooting it. The official micro python board includes a micro SD card slot, 4 LEDs, a switch, a real-time clock, an accelerometer and has plenty of I/O pins to interface many peripherals. A nice video can be found on the campaign page and an interview with the project creator is embedded after the break.

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