What’s inside the Keithley 2400 Source Measure Unit?
EEVblog #718 – Keithley 2400 SMU Teardown – [Link]
by Martin @ harizanov.com:
The WiFi SSR board project changed a bit and I use classical relays instead of SSRs now. The reason is that SSRs tend to get quite hot when switching larger loads, and the 8A relays I last used actually could be used for max 2.5A load switching with no heat sink. The high quality relays I now use allow 10A load switching and are rather quiet. I also changed the design a bit so that it would fit in a box (DIN rail compatible) for increased safety.
WiFi Thermostat with weekly scheduler – [Link]
Project has been designed to record & playback multi voice massages using Winbonds ISD1740 IC. Messages are stored in flash memories made in unique Multilevel Storage Technology (MLS). Circuit provides high quality audio recording and simple operations. Circuit operates in dual mode standalone or micro-controller SPI mode. Onboard tactile switches for standalone mode and 10 (2×5) pin box header connector for SPI mode. 26 to 80 Seconds voice massage recording capacity.
– Supply 2.4 to 5 VDC (5 VDC @ 100 mA)
– 26 to 80 Seconds selectable voice recording capacity
– Selectable sampling rates 11.5 KHz, 7.8 KHz, 6.4 KHz, 5.3 KHz, 4.5 KHz
– Directly drive 8 Ohms speaker or typical buzzer
– Analog audio out to driver external audio amplifier
– Digital volume control via onboard tactile switch
– Dual mode operation stand alone or micro-controller
– SPI Interface (4 wire serial interface)
– 10 (2×5) Pin box header for SPI interface
– Full control on memory and analog path configuration audio input, output and mix in SPI mode
– Automatic power-down after each operations cycle (standalone mode)
– Onboard tactile switch for Record, Play, Erase, FWD, Volume control, Reset and Feed-Through
– Onboard power indication, record play indication
– Voice message fed in via microphone or analog signal in
– ISD1740 provides a PWM class D speaker driver and speaker output simultaneously –
– 100 Years message retention
– 100,000 Record cycles
– Four mounting holes of 3.2 mm each
– PCB dimensions 80 mm x 76 mm
20 to 80 Seconds Voice Record Playback with SPI control – [Link]
The Mini Audio Amplifier project is a good choice for battery operated gadgets. It is based on Texas instruments LM386 IC, provides high quality Audio.
– Wide power supply input 6 to 12 VDC
– 500 mW output @ 8 Ohms load
– Takes standard audio signal as input
– Low quiescent current drain 4 mA IC
– The quiescent power drain is only 24 mW when operating from 6 VDC
– Onboard preset for volume adjust
– Header connector for connecting power supply, audio signal and speaker
– Onboard power indication LED
– On/Off PCB mounted slide switch for power supply
– Four mounting holes of 3.2 mm each
– PCB dimensions 41 mm x 41 mm
Mini Audio Amplifier – [Link]
At the Embedded World conference held in Nuremberg, Germany this week Silicon Labs unveiled its Blue Gecko platform aimed squarely at Internet of Things applications. Silicon Labs have combined both their EFM32 Gecko MCU technology together with a 2.4GHz Bluetooth Low Energy transceiver (including a power amp and balun giving at least +10 dBm output power) on one die.
The 32-bit MCU inside the wireless SoC runs Bluetooth protocol stacks and scripting language developed by Bluegiga. Blue Gecko SoCs are based on ARM Cortex-M3 and M4 cores with 128 to 256 Kbyte flash and 16 to 32 Kbyte RAM. Silicon Labs are offering the complete Bluegiga Bluetooth Smart software stack for Blue Gecko modules and wireless SoCs. The stack implements the Bluetooth Smart protocol layers including the Attribute Protocol (ATT), Generic Attribute Profile (GATT), Generic Access Protocol (GAP) and security manager together with connection management.
Blue Gecko for the IOT – [Link]
PMP9194 uses the TPS54020 synchronous-buck SWIFT converter with integrated FETs to provide a 10A/1V solution in less than 22mmx12mm of total board space area. This reference design uses a small 1.1uH inductor, 2x100uF ceramic output capacitors, and small 0402 external components to save space. The device switches at 300kHz and acheives 87% peak efficiency from a 12V input to a 1V output. The TPS54020 is ideal for powering low-voltage, high-current DSPs and FPGAs, and can be synchronized 180 degrees out-of-phase with another TPS54020 to reduce input ripple.
4.5V to 17V Input, 10-A Synchronous Buck Converter Optimized for Small Size and Low Output Voltage – [Link]
by Susan Nordyk @ edn.com:
The latest addition to STMicroelectronics’ portfolio of environmental sensors, the UVIS25 provides a direct digital output of UVI (ultraviolet index)—the international measurement of the strength of ultraviolet radiation, primarily from the sun, at a given place and time. Aimed at wearable devices, smart-phone, and tablet applications, the UVIS25 is sensitive to UV waves in the 200-nm to 400-nm range. This range covers the UV-A (315-nm to 400-nm) and UV-B (280-nm to 315-nm) wavelengths, which are of greatest concern to human health.
The device furnishes more than just sensing, calculating the UVI internally and eliminating the need for external processing algorithms or calibration on the customer’s manufacturing line. Key specifications include a UVI output range of 0 to 15 with a resolution of just 1/16, SPI and I2C interfaces, a supply voltage range of 1.7 V to 3.6 V, and the ability to provide updated UVI values as often as every second.
UVIS25 – Wearable sensor measures UV index – [Link]
by sajjad Haidar @ edn.com:
A simple blocking oscillator circuit can be used to step up voltage using properties of coil inductance (V = L di/dt). Such a circuit is shown in Figure 1, which is more commonly called a Joule thief.
The output will be pulses of voltage that can be filtered using a diode and capacitor. As there is no regulation, the output voltage will vary with the input voltage or load. As this circuit uses a BJT, the supply voltage needs to be at least 0.7V to work, and with enhancement-mode MOSFETs, the supply voltage must usually be even higher.
MOSFET-based Joule Thief steps up voltage – [Link]
by CsabaP @ instructables.com:
This Instructable shows you how to build a clap activated LED strip. The whole project is based on the Adafruit’s Secret Knock Activated Drawer Lock, where the user can record a secret knock pattern which will open the lock inside the drawer. I thought that I could use this to siwtch an LED strip on and off with a handclap pattern. So let’s begin!
Clap activated LED strip – [Link]
by BinksBrew @ instructables.com:
For a long time I’ve had old back up cell phones taking up space in my desk drawer. I was curious if I could put any of these old phones to some use. I can’t just throw them away so I decided to try and re-purpose one of them as a portable charger for my current smart phone.
Portable Charger for your Smartphone – [Link]