This project is a solution to power up most of devices or projects requiring dual (+/-12V) power supply.
Symmetric +/-12 VDC power supply has been designed for audio applications, can power up microphone pre-amplifier, audio buffers, audio mixer, distributions amplifier, headphone amplifier, VU meter and few o other equipment or projects required dual supply.
+/-12V Dual Power Supply - [Link]
Miniature calibrated humidity and temperature sensor Sensirion SHTC1 is usable even in space – limited applications.
Really miniature dimensions and a low price are main benefits of new calibrated sensors SHTC1 from production of company Sensirion. If you ever tried well known sensors series SHT2x, probably you´ve been surprised by their small dimensions (3,2×3,2x2mm). However the new sensor SHTC1 shifts dimensions a level further, or better said – lower. The result is a DFN package with dimensions of only 2x2x0.75mm, what in praxis represents a package, which you may not notice at a cursory look at a populated PCB. That´s why the SHTC1 is primarily intended for mobile applications and everywhere, where a spared space and a minimal power consumption are beneficial.
Taking a low price in mind, the guaranteed accuracy of SHTC1 chip is relatively excellent, roughly on a level of SHT21. Typical accuracy of ±3% in a range of 20-80% RH and ±0.3°C is probably fully sufficient for majority of applications. 1.8 V supply voltage and ultra low power consumption below 1uJ/measurement are ideal for battery powered devices. SHTC1 supports I2C fast mode (0-400 kHz). This small package practically can´t be soldered by hand, but it is relatively easily possible by means of a solder paste and a hot-air soldering station.
Also the SHTC1 is produced by a well proven CMOSens technology, which proves its reliability and a long-term stability in industry. Similarly, the SHTC1 also isn´t only a “sensor” but a ready-made calibrated solution containing 2x sensor, low-noise amplifier, A/D interface, data processing unit with calibration data in a ROM and a communication interface. Detailed information can be found in the Sensirion SHTC1 datasheet and the Sensirion Humidity flyer.
We´ve got samples ready for you!
If you´re interested in trying this perspective sensor, take part in a contest below the article, or contact us on a well known address email@example.com.
SHTC1 we keep so far as an item upon order, but we´re able to supply it to you in a short leadtime and soon it will be a standard stock item.
SHTC1 – humidity and temperature from a pin head - [Link]
Ray has a great reverse engineering project! Check out more on his blog rayshobby.net. [via]
At the Maker Faire this year I got lots of questions about soil moisture sensors, which I knew little about. So I started seriously researching the subject. I found a few different soil sensors, learned about their principles, and also learned about how to make my own. In this blog post, I will talk about a cheap wireless soil moisture sensor I found on Amazon.com for about $10, and how to use an Arduino or Raspberry Pi to decode the signal from the sensor, so you can use it directly in your own garden projects.
What is this?
A soil moisture sensor (or meter) measures the water content in soil. With it, you can easily tell when the soil needs more water or when it’s over-watered. The simplest soil sensor doesn’t even need battery. For example, this Rapitest Soil Meter, which I bought a few years ago, consists of simply a probe and a volt meter panel. The way it works is by using the Galvanic cell principle — essentially how a lemon battery or potato battery works. The probe is made of two electrodes of different metals. In the left picture below, the tip (dark silver color) is made of one type of metal (likely zinc), and the rest of the probe is made of another type of metal (likely copper, steel, or aluminum). When the probe is inserted into soil, it generates a small amount of voltage (typically a few hundred milli-volts to a couple of volts). The more water in the soil, the higher the generated voltage. This meter is pretty easy to use manually; but to automate the reading you need a microcontroller to read the value.
Reverse engineer a cheap wireless soil moisture sensor using Arduino or Raspberry Pi - [Link]
by R-B @ embedded-lab.com:
This electronic dashboard for a bicycle uses an Arduino and a few other parts to create a light control system and an LED speedometer. It is powered with eight 1.5V batteries connected in series. Six LEDs on the dashboard indicates how fast are you going on your bicycle.
Electronic dashboard for a bicycle - [Link]
Integrated Device Technology has released what is said to be the world’s smallest 2W contactless-charging power receiver chip. In the future when all our internet-connected portable and wearable devices need a recharge after a busy day with their head in the cloud, contactless charging will be the way to go. The IDTP9026 wireless-charging receiver chip has a board footprint of just 30 square millimetres and is designed to charge a standard lithium-ion battery rated at 4.2 V. An AD pin allows the device to be switched out of the charging circuit when an external adapter is used for recharging. A separate enable pin is also available to turn the device off.
Receiver Chip for Wireless-Charging - [Link]
App note (PDF) on automobile flashers from Texas Instruments:
This Application note presents the design of a low cost, flasher circuit with short circuit protection. The design incorporates the entire recommended design feature set for two wheeler flashers and includes low/high voltage operation, half load frequency doubling, and short circuit protection.
App note: Design of a low cost, 45W flasher with short circuit protection using LM2902 - [Link]
Dave shows some techniques on how to build and mount usable PCB based front panels user interfaces with LCD displays and push buttons and capacitive touch buttons onto small cheap extruded aluminium enclosures.
EEVblog #644 – How To Design Front Panels On Extruded Enclosures - [Link]
Flat displays of the EA DOG series are now available even with a bigger resolution or with more characters.
EADOG series is familiar to many of you and probably it´s your favorite one from these main reasons:
- displays are unusually flat (thin)
- the have a very low power consumption of 100-s uA (without backlight)
- wide possibilities of backlight, monochrome and also RGB
- some types are well legible even without backlight
- simple communication through 4/8 bit or SPI interface and newly even I2C
So far, types with up to 128x64px or 3×16 characters were available. The most recent additions to the EADOG family are bigger types with resolution of 160x104px (EADOGXL160), 240x64px (EADOGM240), 240x128px (EADOGXL240) and 4×20 characters (EADOGM204) and appropriate backlight modules EALED66x40, EALED94x40 and EALED94x67. Also these new types maintain a low profile – only 5.8 or 6.5mm with backlighting. A positivity is that even these new types are based on standard LCD controllers.
A guide at a choice of a suitable combination of display +backlight will provide you the application described in our article – Start with the EA DOG displays for free.
Detailed information will provide you the datasheets at particular types.
EA DOG displays with a minimal power consumption now available in bigger sizes - [Link]
Clap switch/Sound-activated switch designed around op-amp, flip-flop and popular 555 IC. Switch avoids false triggering by using 2-clap sound. Clapping sound is received by a microphone, the microphone changes the sound wave to electrical wave which is further amplified by op-amp.
555 timer IC acts as mono-stable multi-vibrator then flip-flop changes the state of output relay on every two-clap sound. This can be used to turn ON/OFF lights and fans. Circuit activates upon two-clap sound and stays activated until another sound triggers the circuit.
Sound Activated Switch - [Link]
By Sophi and Garrett @ element14.com
The new version of Eagle is on out! The biggest changes coming are a new design feature and an improved autorouter. We are both veterans of Eagle and PCB board design so this blog is intended as both a review and a tutorial of the new features that Eagle v7 brings. Let’s dive right in.
To make the design process more real, we decided to design a circuit from scratch. A simple circuit that Sophi has worked with is one that uses an audio signal to control a hobby servo, which could be used to control an animatronic. It’s a little early for Halloween, but Sophi had used this circuit before and planed on using it again in October. Many thanks to Scary Terry who gave us permission to use his design.
Eagle v7 Beta Review - [Link]