Electronics-Lab.com Blog

The heart of the circuit is the LM35 temperature sensor which is factory-calibrated in the Celsius (or Centigrade) scale with a linear Degree->Volt conversion function. The output voltage changes with temperature from 550mV (-55oC) to 1500mV (150oC). This greatly simplifies the thermostat designed only need to provide a precision voltage reference (TL431) and an accurate comparator (A1 of LM358) in order to construct a complete thermostat.

Electronic Temperature Controlled Relay - [Link]

The circuit make good use of the on-chip comparator in a single 12F675 PIC to detect the low level data and clock signals from the scales.

The firmware reads both 24 bit binary and 7 digit BCD output scales types, can switch the scale to fast or slow reading, zero the scale display and outputs the data in an easily readable format at 115,200 Baud.

Reading the data output from cheap digital verniers and scales - [Link]

youritronics.com writes:

I liked the tvbgone kit from Ladyada the first time i saw it but i never had the time to build it, until a week ago. But than i decided to build a more powerful one that could turn off TV’s from even greater distance. I came up with a design that consists of 48 IR LED’s and a ATmega8 that will send the signals to the LED’s.

Super TV-B-Gone - [Link]

Today i came across this nice piece of equipment. It is a Solar cell characterisation instrument with build in LCD screen to view the characteristics of photovoltaic module under test. I couldn’t find an online dealer for this device or a datasheet. Main features are:

• I-V Curve Test for Solar Cell.
• Maximum Solar Power (Pmax) Search by Auto-scan (60V, 6A)
• Maximum Voltage (Vmaxp) at Pmax
• Maximum Current (Imaxp) at Pmax
• Voltage at open circuit (Vopen)
• Current at short circuit (Ishort)
• I-V curve with cursor
• Optional printer (model: 300XP) to hardcopy I-V curve
• Calculation of Efficiency (%)
• Manual single point test

Solar Module Analyzer - [Link]

Do you like the way Mac status led pulses like it is breathing? Then build your own with simple parts. Anybody who?s seen a G4 knows it. That power LED that fades in and out. Figured that’d make a sweet addition to a modded case, especially since it’s less then $3 in parts. Besides, why should them Mac people have all the fun?

Pulsing LED - [Link]

This is an electronic digital caliper to computer (RS-232) interface. This will work with the inexpensive calipers, micrometers and height gauges that are typically made in China. The connector on the measuring instrument will have 4 pins, and the owner’s manual will typically describe the output as 24 bit 90 kHz synchronous. This does not work the name brand instruments - Fowler, Mitutoyo, Brown & Sharpe, etc.

The caliper sends a burst of data approximately three times each second. Each burst contains 48 bits of data as shown in timing.pdf. The first 24 bits are the position relative to the zero point set on the caliper. The second 24 bits are the position relative to an arbitrary zero that does not change. This is sort of an absolute position, but the zero point changes each time the caliper loses power. Each 24 bit value is in ones compliment form (1 sign bit, 23 data bits). This allows for a 0 and a -0. The unit of measure is 1/20480th of an inch. [image source: www.hobbytoolsupply.com]

Digital caliper to computer (RS-232) interface - [Link]

The SDL-1 Solar Data Logger is useful to anyone wanting to know how much solar power can be produced from the available sunlight (solar insolation) at their location. It is a self-contained solar energy meter that measures and records the sun’s irradiance at regular intervals for up to 170 days at a time. It also reports the cumulative incident solar energy that the data logger receives during its deployment.

• Logs solar irradiance and cumulative incident energy
• Accuracy: &plusmn5% at 25&degC
• Logs up to 170 days of data
• Weatherproof enclosure
• USB interface
• Battery life: 2 years

SDL-1 Solar Data Logger - [Link]

SquidBee is an Open Hardware and Source wireless sensor device. The goal of SquidBee is getting an “open mote” to create Wireless Sensor Networks (WSN).

How does SquidBee work?

• Acquires values from environment parameters: temperature, humidity, lightness, presence, pressure or (almost!) whatever you can sense
• Operates with these values, when required
• Transmits these values using a low power comsumption wireless technology (ZigBee)
• Sleeps until next timeout and repeats from the first stept

SquidBee: Wireless sensor device - [Link]

Low Power Radio Solutions (LPRS) has claimed that its easy-Radio allows you to ignore the radio link and treat it as if it were a wire. A simple TTL or RS-232 data source is all that’s required to move data from point A to point B, and vice versa, using a pair of easy-Radio transceivers. All of the messy encoding, decoding, and checksum calculations are achieved by the easy-Radio’s internal processor. easy-Radio uses frequency hopping and a maximum of 120 mW of output power to achieve a range of 500-m line-of-sight. My 900-MHz easy- Radios hop at 25 times per second over 25 channels, which, under the control of the internal microcontroller, is transparent to the data radio user.

RF Made Simple - [Link]

Whether you are looking to control an RC helicopter or a full-sized car, this system will work for you. By facilitating communication between a base station and a vehicle, the system enables an operator to process commands and receive data.

Flight Control: A Communications System for an RC Helicopter - [Link]