Low-power MCU module makes sense of laser data

The RCM3375 RabbitCore module collects serial data from a displacement laser sensor in the ground-breaking Ames LTS9200 laser texture scanner.

Ames Engineering located in Ames, Iowa, is one of the leading manufacturers of profiling equipment for measuring the structural integrity and performance of paving materials.

Most often this type of equipment covers large areas and requires specialised vehicle mounting.

Paving contractors and government agencies predominantly use Ames's products for quality control, quality assurance, and measurement of smoothness.

The company realised that a portable solution was needed to take quick, accurate measurements at any place at any time.

Ames developed the LTS9200 laser texture scanner, a laser-based texture-scanning device that can be used to measure texture of any flat surface on the spot.

The portable scanner can cover an area up to 100 x 75mm, and calculate standard indexes that are used to determine surface texture such as root-mean-square (RMS) and mean profile depth.

At the heart of the LTS9200 is the RCM3375 RabbitCore module, which collects serial data from a displacement laser sensor.

The measurements help determine if the pavement will have tire noise or traction issues.

Once the scan is complete, information such as mean profile depth, texture profile index, and estimated texture depth is immediately available via the LCD.

All the information is stored in a simple CSV file on the RCM3375 via the removable storage.

The information can be transferred to a PC using Ethernet via the module's 10/100Base-T Ethernet port.

The FAT File software module enables PCs to read the downloaded scan data, allowing for ease of transferability and usability.

With a high cycle rechargeable battery, the LTS9200 can perform up to 100 scans per charge.

Ames Engineering found the RCM3375 to be the right fit for its application because it needed a low-power solution that could be battery operated for many hours, allowing for extreme portability.

The RCM3375 features removable media card slot for increased memory storage.

"The FAT file system software module along with the 128Mbyte media card worked well for storing scan files out in the field", said Mark Leichty, Chief Engineer at Ames Engineering.

The networking capability of the RabbitCore was a plus for their embedded design.

"The web server capabilities of the Rabbit module worked well for a simple user interface and file downloads", said Leichty.

"We also use the web server interface to allow the user to remotely control scanners in real time from any desktop on a local network".

The RCM3375 offers plenty of I/O, allowing for direct connectivity to LCDs, motors and switches.

Three serial ports are used on the RCM3375 core module.

One serial port is used to communicate with a built-in GPS receiver, the second serial port is connected to a serial interface on the laser, and the third serial port communicates with a PIC processor, which is used for battery charging and monitoring.

"The RCM3375 basically had all the I/O we needed to interface all these devices in one nice package".

"The media card was also nice for storing all the data from the texture scans", explained Leichty.

Dynamic C along with sample files also helped to speed up development.

"Development time was shortened because of our familiarity with the development tools, and also because of the many nice example files that are included with Dynamic C", Leichty said.

Rabbit's RCM3375 proved to be the perfect choice for Ames Engineering and its texture-scanning device.

In one small package, the RCM3375 offered the right features to enable portability, plenty of memory storage and ease of use.

Dynamic C and the sample programs allowed for quick development and ease of integration.

The RCM3375 and Dynamic C gave Ames Engineering and its LTS9200 the edge needed to go well beyond the surface.

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