Here is an up-down counter based on PIC16F88 and 7-segment display. The counter is using SMD components and features a RS-232 interface.
This is a simple digital counter with a serial rs-232 and a 7 segment display, i started this project to count items on some shelfs, but it can be used for anything, it is also, for the exception of the connectors, completely on SMD components.
UP/DOWN counter with memory using PIC16F88 – [Link]
Reno Rossetti & Inyong Kim discuss about the power needs on portable devices and help us choose the right regulator.
A popular power source for portable devices is a single lithium-ion cell with 4.2V at full charge and 2.8V at end of discharge. However, some functions within portable electronics, such as a SIM card and DSP, require 2.8V and 3.3V. These are normally provided by low noise LDOs. The LDOs inputs (VCC) must be at a slightly higher voltage than the highest LDO output. Hence, VCC ends up right in the middle of the lithium-ion battery’s range of operation.
Choose the right step-up/down voltage regulator for portable applications – [Link]
Linear Technology Corporation introduces the LTC7813, a dual output (boost + buck), low quiescent current synchronous DC/DC controller. When cascaded, its independent step-up (boost) and step-down (buck) controllers regulate the output voltage from an input voltage that can be above, below, or equal to the output voltage, including during an automotive load dump or cold crank. Unlike conventional single inductor buck-boost regulators, the LTC7813’s cascaded boost + buck solution provides fast transient response with continuous, non-pulsating input and output currents. It substantially reduces ripple voltage and EMI, ideal for automotive, industrial and high power battery operated systems.
LTC7813 – Low IQ, 60V Synchronous Boost+Buck Controller – [Link]
Fabio Bergamin @ phys.org writes about PULPino which is an open source processor to be used on wearables and IoT.
In future, it will be easier and cheaper for developers at universities and SMEs to build wearable microelectronic devices and chips for the internet of things, thanks to the PULPino open-source processor, which has been developed at ETH Zurich and the University of Bologna.
Open-source microprocessor – [Link]
Andy published his accurate and open source frequency counter that uses an Android phone as a display. It’s based on a high accuracy temperature compensated crystal oscillator (TCXO) fed into a phase locked loop (PLL) to create a high frequency reference clock. The reference clock along with the input signal is processed by a Xilinx FPGA and a STM32F072 mcu is reading the data.
Here we have a good example of how a requirement for a simple tool spirals out of control and spawns a project that takes months to complete and ends up dwarfing the project that it was originally expected to facilitate. You see, some time ago I was fiddling around with a project, something to do with data logging, probably, I’ve actually forgotten what I was up to.
Nanocounter: Frequency Counter with an Android Interface – [Link]
This is a small hot-plate for SMT reflow soldering build upon an Arduino Pro and controlled using PWM and high side power MOSFETs.
Black Mesa Labs has been using a $20 hot plate for a year now for soldering QFN ICs to PCBs. Only issue so far has been the size ( 10″x10″x3″ ) and thermal mass of the thing as it consumes precious microscope work area and unfortunately stays quite hot for 30+ minutes after a quick 4 minute reflow job. BML boards are mostly 1″x1″, so a 800W hot plate with a 6″ diameter heating surface is overkill for most jobs.
1″ 100W Hot-Plate for SMT Reflow – [Link]
VoCore is an open source hardware that runs OpenWRT Linux. This tiny computer comes with Wi-Fi, USB, 20+ GPIOs that will help you to embed it on your projects.
With each passing day, mini computer boards are getting more and more popular. Single board computers like Raspberry Pi, CHIP, OrangePi etc. are being endorsed by makers and DIY enthusiasts to create new innovations. However, if you are looking for an even smaller Linux computer, VoCore is the perfect device for you.
VoCore: A Cheap And Coin-sized Linux Computer With Wi-Fi – [Link]
Bob tipped us with his latest project, it’s a 9V to 1kV DC-DC converter using CD4011 IC to produce a square wave and a IRF530 transistor to drive the transformer.
Finally, I have made a new high voltage supply based on an inverter transformer and voltage doubler. It seems to be ok for this job, but it can be used in various other applications so I’m presenting it in a separate entry.
Warning! the device produces high voltage that can be lethal, if you want to build it, please take cautions.
9V to 1kV DC/DC converter – [Link]
Dual DC Motor driver using two L293D IC. The L293D device is quadruple high-current half-H driver. The 293D is designed to provide bidirectional drive current up to 600mA a voltage from 5V to 36V. It provides 600mA +600mA on each channel suitable for mini hobby robots. The board been designed mainly for small size robot, however this can be used for other application where two motor control required. L293D includes the output clamping diodes for protections. Each channel required two input signals PWM and DIR for full control. Separate logic supply to reduce dissipation.
- Motor/Logic supply 5 to 36 V
- Logic controls input 7 VDC max
- Inhibit facility/enable
- PWM Frequency 5KHz Maximum
- High Noise immunity
- Over temperature protection
- Capable of delivering output current up to 600 mA per channel
- The control/interface lines are accessible with Berg connector
- Header connector for motor and supply connection
Dual DC Motor driver using two L293D – [Link]