Data Logging

Self-Powered Solar Data Logger

My project is a self-powered solar data logger. Put out in the sunlight, it will measure the light level and log this to memory to be later downloaded to a computer. The system is powered by a small solar panel and battery. The solar logger I built uses a photodiode to measure the solar insolation level. It converts the analog signal from the photodiode to a digital value that is stored in flash memory. Every time the system logs a data point, it also logs the time and date so that the data can be analyzed in the future. The logged data is available for a user to download to a computer for analysis. While the system is logging, real time data is displayed on a small LCD screen as well as information about the battery voltage, the length of time the system has been logging and the length of time it can continue to log before running out of memory. ..

A follow up Mk2 version described by EA`s Jim Rowe in the May/June/July 94 issues of EA improved on the original with calibrated time and vertical scales, and extra triggering features. This design proved even more popular than the first, proving that there is a genuine need for such a low audio bandwidth PC based scope...

This article details the construction of a bench top power supply that can be used to power circuits or devices during development work in the lab. More specifically it is an adjustable, tracking, dual rail supply which means there are two supply voltages, one positive, one negative, that are adjusted by a common potentiometer such that supply voltages are equal in magnitude. It is capable of supplying up to +/- 15V DC at up to 1A. This is sufficient for the majority of small signal electronic projects...

Just a handful of components builds an 8-pin microcontroller based circuit for temperature logging via a serial port; small, fast, and acceptably accurate...

This circuit is a simple 8-bit analogue to digital converter circuit which is connects to PC serial port. The circuit is based on TLC548 A/D-converter chip (might be hard to get nowadays, Texas Instruments makes this IC), which is an A/D-converter with serial output...

The new data-logger software is not yet completely finished. But the hardware design is frozen and will probably not be changed anymore. The printed circuit board is a bit smaller than the old one (36x22mm). But unfortunately the new one can measure analog input signals only with 10 bit resolution...

The asynchronous RS-232C interface is a simple, low-cost option for interconnecting processor-based systems, but this character-oriented interface supports no direct mechanism to transfer variable-sized messages as self-contained data packets. However, you can use the DTE-DCE handshake lines, namely DTR and DSR, to implement packet-level data exchange. The proposed method interconnects the DTR and DSR of the two systems and uses these lines to indicate packet boundaries...

This circuit is intended for precision centigrade temperature measurement, with a transmitter section converting to frequency the sensor`s output voltage, which is proportional to the measured temperature. The output frequency bursts are conveyed into the mains supply cables. The receiver section counts the bursts coming from mains supply and shows the counting on three 7-segment LED displays. The least significant digit displays tenths of degree and then a 00.0 to 99.9 °C range is obtained...

This is a simple wireless remote control unit, which was originally designed for a model hovercraft which I was developing with the help of my friend Uday Arya. The project has been discontinued for technical reasons, but this remote control unit survives. The method used seems to be quite popular among many remote control units...

With our design, it takes two readings by the RCX to get one complete reading from the compass sensor. Software then must combine those readings together to determine the angle the compass is pointing. We had to do it this way because of power demands by the Dinsmore part and power limitations of the RCX...

Many applications require high-resolution, multichannel, large-bandwidth signal acquisition. Some examples are vibration analysis, vehicle telemetry, and telecommunications. You could use an array of A/D converters to address such applications, but ADCs are costly and consume considerable board space. Figure 1 shows a complete and cost-effective, high-speed, differential, eight-channel, 12-bit acquisition system that uses few parts...

This is the electronic schematic of the homebuilt SONAR. Only one piezoelectric tranducer is used for both tramsmit & receive. This transducer is switched from TX to RX via the four 4016 switches. A high gain amplifier stage & rectifier translates the received echoes into voltage pulses. The timing is controlled by the PIC12C508 8-pin microcontroller as it is shown in the following figure:..

The asynchronous RS-232C interface is a simple, low-cost option for interconnecting processor-based systems. In many applications, you need to transfer variable-size messages. However, the character-oriented RS-232C protocol offers no direct mechanism for transferring messages as self-contained packets. The method described here uses an obscure feature found in most UART devices to indicate packet boundaries...

The circuit is designed to be low cost. It uses a PIC12C508 to perform the control functions and standard 40khz piezo transducers. The drive to the transmitting transducer could be simplest driven directly from the PIC. The 5v drive can give a useful range for large objects, but can be problematic detecting smaller objects. The transducer can handle 20v of drive, so I decided to get up close to this level. A MAX232 IC, usually used for RS232 communication makes and ideal driver, providing about 16v of drive...

A project required building a synchronous-demodulator circuit to track a line drawn on paper. The beauty of the synchronous-modulator/demodulator approach is its inherent noise rejection. The method rejects nearly all out-of-band noise, whether from internal drift or external illumination. This rejection is a boon in optical tracking, where the return signal is inevitably buried in 120-Hz ambient light, amplifier offsets, and temperature drifts...