LCP2138 controlled inertial robot

This project represents a one-wheeled rolling robot that runs by using inertia moment. It has two actuators – driving and steering. Robot is also capable to perform reconnaissance and cooperative tasks. Mechanics is pretty simple – inertial driving force is created by attaching a mass to DC electric motor. Inertial allows not only drive but also jump over obstacles if necessary. Steering is provided by using servo motor which actually tilts axis of rotation. Robot is controlled by LPC2138 Arm microcontroller which is a part of Keil MCB2130 evaluation board. Microcontroller as usually generates PWM waveform to drive motors. Using an ARM microcontroller there are lots of room left for improvements like adding additional sensors like gyros, accelerometers or other intelligence. Continue reading

NXP ARM Cortex M0 based Wikipedia reader

This project appears to be very impressive and useful especially if you like to keep eye on Wikipedia. Actually this is an offline reader that renders offline xml dumps in to readable text. Device is built on NXP ARM Cortex microcontroller (LPC1114) that is capable of running at 72 MHz and has 32K flash along with 8K SRAM. Information is displayed on inexpensive touch screen LCD based on ILI9325. Wikipedia xml dumps are stored in microSD card. Schematics aren’t ready yet but author promises them soon after some polishing. Continue reading

Audio effects on mbed platform

Mbed platform is based on LPC1768 microcontroller which has a great power to perform most signal processing in audio level. Current effect generator is fairly simple as it uses a standard electret microphone that is connected through several stages of OP amps operating as buffer, amplifier and low pass filter (10-15kHz). Then signal enters a microcontroller for some processing. And then signal leaves microcontroller via DAC  to output amps. Effect platform is doing great job. It can do simple tasks like delay, echoing. For more audio effects there is more complex signal processing needed like FFT and digital filtering where DSP processor would be better choice. But still mbed platform is quite powerful to try more. Continue reading

New BlueBoard-LPC1768-H has been released

Continuing with its endeavor to deliver low cost micro controller hardware development platform, NGX has now launched a new low cost prototyping platform for LPC1768 series of mircocontrollers. LPC1700 are ARM cortex-M3 based micro controllers. The platform is named BlueBoard-LPC1768-H and costs only $32.5 BlueBoard-LPC1768-H is a breakout board for LPC1768 cortex-M3 based microcontroller. The LPC1768 microcontroller has 512KB of internal flash and 64KB RAM. Ethernet MAC, USB Device/Host/OTG interface, 8-channel general purpose DMA controller, 4 UARTs, 2 CAN channels, 2 SSP controllers, SPI interface, 3 I2C-bus interfaces, 2-input plus 2-output I2S-bus interface, 8-channel 12-bit ADC, 10-bit DAC, motor control PWM, Quadrature Encoder interface, 4 general purpose timers, 6-output general purpose PWM, ultra-low power Real-Time Clock (RTC) with separate battery supply, and up to 70 general purpose I/O pins Board can be purchased from Following are the salient features of the board. * Dimensions: 94.08×54.48 mm2 * Two layer PCB (FR-4 material) * Power: USB powered or can be powered through the DC jack, 5-7.5V input * reset switch * Test LED * 32Khz crystal for RTC * On… Continue reading

LPC2138 based power level monitor

Are you feeling tired of paying large electric bills? Probably you feel that some tweaking in home electric system would save couple bucks. So why not to try, but for this you will probably need a power level monitor to determine where are biggest usage of electric. Building power level monitor can be quite easy – there can any microcontroller be used for this. In this case a LPC2138 ARM7 microcontroller has been chosen which, I think, probably is too powerful for such simple task. The simple idea of design is to sense current and step down voltage to level acceptable to MCU IO ports. The current sensor is made of transformer with some modifications. Device detects zero crossings of voltage and current in order to determine the phase shifts so it could calculate power RMS correctly. Power level information can be viewed in two ways – via 7 segment LED indicator mounted directly on device or it can be sent via USART to monitor it computer screen and probably so some statistics. The full project can be downloaded here. Continue reading

Audio spectrum analyzer without DSP processor

When dealing with signals, probably the best way is to leave the task for DSP processor as they are optimised to do DSP calculations like FFT, filtering and other digital signal manipulation. But not always a DSP processor is an only solution, especially if you want a low cost and non-critical performance application like an audio spectrum analyser. In this project, an ARM7 (LPC2138) microcontroller is used to do an FFT algorithm. The tricky part about FFT on such microcontrollers is dealing with complex numbers that are also real. The project description shows the whole process of how these problems are solved. Project is set up on ZL6ARM prototype board, which is equipped with all necessary peripherals like LCD, MAX232 converter. The program is developed for ARM-GCC compiler. An audio signal is sampled by LPC2138 internal ADC with the selected sampling frequency of 40 kHz. An FFT algorithm calculates the chunks of 256 samples and produces the spectrum graphs on the PC screen. This is a great project and nice tutorial to get into DSP world. [source] Continue reading