Tag Archives: WLS

Water Level Logger – voltage level conversion

Posted on 2014/03/31 by andy

Digital subsystems with different supply voltages have to align their logical states if they want to talk to each other. It can be done with variety of discreet components as well as dedicated integrated circuits. It is simple task these … Continue reading →

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Water Level Logger – efficient 3.3V supply

Posted on 2014/03/09 by andy

Problem is simple: 3.3V DC/DC converter has to work with high input voltage (>20V), has to be highly efficient as it works continuously in energy scarce conditions, and has to provide up to 300mA dealing with SD card bursts without … Continue reading →

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Water Level Logger – solar charger

Posted on 2014/02/17 by andy

It was my first work on photo-voltaic and rechargeable batteries technology. I have read a lot about mono- and poly-crystalline cells, tracking the highest efficiency points of panels (MPPT) or proper charging/discharging. Facing that I felt I have long way … Continue reading →

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FreeRTOS tickless idle on Atmega128

Posted on 2014/01/23 by andy

Real-time operating system (RTOS) makes embedded coding more elegant and maintainable if MCU has to take care of many things at the same time. FreeRTOS also supports many platform including  8-bit AVRs. I am using it because of both reasons. … Continue reading →

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Water Level Logger – overview

Posted on 2014/01/13 by andy

The logger part of Water Level Station experiment was second in line for design and development. The transmitter measuring water level was done first and turned to be just a warm-up comparing to logger feature list: self-powered unit with multitasking … Continue reading →

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Water Level Transmitter – surge protection

Posted on 2013/11/20 by andy

Thunderbolt that hits near a long cable line can induce spike of hundred of volts. Budgetary RS-485 driver will not protect circuitry from damages caused by over-voltage and over-current. While scorched prototyped device makes constructor sad, failure to bunch of … Continue reading →

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Water Level Transmitter – RS-485

Posted on 2013/11/05 by andy

Serial transmission over long line was the last stage of first iteration in prototyping. Local communication between microcontroller’s USART and PC was already working with MODBUS thus adding RS-485 driver and couple passive elements meant to be piece of cake. … Continue reading →

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Water Level Transmitter – microcontroller

Posted on 2013/10/18 by andy

Once the signal from sensor is converted in ADC it has to be processed and delivered to remote master unit. Having extra local measurements sources, like temperature, it has to be combined altogether. Multiple transmitters coexisting on single line (bus) … Continue reading →

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Water Level Transmitter – digitization

Posted on 2013/10/09 by andy

It was a long and bumpy way from taking pressure transducer hardware in my hands to having stable digitized values. Most of the time I spent learning instrumentation circuitry from app notes and books, just to make sure the solution … Continue reading →

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Water Level Transmitter – overview

Posted on 2013/10/01 by andy

One of methods for automatic water level metering is to put a waterproof pressure sensor under the surface at well-known absolute depth and measure hydrostatic pressure that translates into the level of water over the pressure sensor. There is a … Continue reading →

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