Simple, easy and cheap wireless presenter

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by Dimitris Platis @ instructables.com:

During presentations, I avoid being stationary and generally like to walk around in order to increase the interaction between me and the audience. However, I am constantly being faced with the burden of having to go back to the laptop, in order to change a slide or tell a person sitting by the laptop to do that. Not cool!

This problem is usually solved by devices, called remote clickers or wireless presenters, which consist of a handheld controller with buttons that sends signals to a USB dongle plugged in the computer. After looking around to buy one, I could not find any decent option costing less than 10$. So why not make one?

Simple, easy and cheap wireless presenter – [Link]

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Meter Clock using a DS1307 RTC and Trinket Microcontroller

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by MIKE BARELA @ adafruit.com:

Trinket lends itself very well to building clock projects, its small and easy to hide behind a larger display. And clocks don’t need a lot of logic, this example only has maybe 20 lines of code. Adding a digital display via I2C is possible using seven segment or character-based displays (with the library code posted for other projects).

This project interfaces Trinket to the the Adafruit DS1307 real-time clock (RTC) breakout board to form a clock. But in a twist, the display is done using two analog meters. One for hours, one for minutes.

The Trinket can output to a meter without digital to analog converters. Trinket has pulse width modulation (PWM) on three of its pins. The meter uses a moving coil inductance movement, acting to average the indication of current flowing through it. If you have narrow pulses, the average voltage it sees is lower, thus the current is lower for the fixed resistance attached to it. For wide pulses, the meter sees nearly the supply voltage and will stay around the full scale. This circuit varies the pulse width sent to the meters proportional to the hour of the day and the minutes after the hour.

Meter Clock using a DS1307 RTC and Trinket Microcontroller – [Link]

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Do you know Hirschman ST industrial connectors?

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Power supplying, control, but also signal transmission from various sensors can be confided to ST series connectors.

A word „versatility“ describes well know series Hirschmann ST (STA) perhaps the best. ST connectors are universal because as for parameters, they´re sufficient for majority of applications (16A/250VAC) and they maintain a decent compcáctness. At the same time, they´re available in many versions (M/F, panel/ cable) , so we can create a desired combination – cable/cable, cable/panel.

ST connectors have 2,3,4 or 5 contacts + PE in a compact polyamid (PA) body. Safety and reliability is supported by a metal lock STASIx (bought separately), preventing accidental disconnection and also enabing a fast disconnection in case of necessity.
Connectors for a cable are also available Kwith an extra cable support against pulling off from a cable gland („strain relief“). ST series is so to say a standard for many industrial applications and it finds its place also for example in building automation (intelligent houses, ….).

A novelty in our portfolio is price-gainful set called SETSTAx3 for a cable+cable connection, containing STAS 3N, STAK 3N and a metal lock.

Detailed information will provide you datasheets at particular types below this article. Upon order, even the surface mount types and types with an integrated cable are available.

Do you know Hirschman ST industrial connectors? – [Link]

Sensored BLDC Motor Control

In a DC motor, the stator is a permanent magnet and the rotor has the windings, which are excited with a current. The current in the rotor is reversed to create a rotating or moving electric field by means of a split commutator and brushes. On the other hand, in a BLDC motor, the windings are on the stator and the rotor is a permanent magnet, hence the term inside-out DC motor is coined.

To make the rotor turn, there must be a rotating electric field, typically a three-phase BLDC motor has three stator phases that are excited two at a time to create a rotating electric field. This method is fairly easy to implement, but to prevent the permanent magnet rotor from getting locked with the stator; the excitation on the stator must be sequenced in a specific manner while knowing the exact position of the rotor magnets. Position information can be gotten by hall effect sensors that detect the rotor magnet position.

The dsPIC30F2010 is a 28-pin 16-bit MCU specifically designed for embedded motor control applications. The six MCPWM pin outputs are connected to three MOSFET driver pairs (IR2101S), which in turn are connected to six MOSFETs (IRFR2407). These MOSFETs are connected in a three-phase bridge format to the three BLDC motor windings. MOSFET drivers also require a higher voltage (15V) to operate, the motor is a 24V BLDC motor so the DC+ to DC- bus voltage is 24V and a regulated 5V is provided to drive the dsPIC30F2010. The three Hall effect sensor inputs are connected to input pins that have Change Notification circuits associated with them. These inputs are enabled along with their interrupt. If a change occurs on any of these three pins, an interrupt is generated. To provide a speed demand, a potentiometer is connected to an ADC input (RB2).

To start and stop the motor, a push button switch is provided at RC14. To provide some current feedback to the motor, a low value resistor (25 milliohms) is connected between the DC- bus voltage and ground or Vss. The voltage generated by this resistor is amplified by an external op amp (MCP6002) and fed to an ADC input (RB1).

Sensored BLDC Motor Control – [Link]

Cypress expands energy-efficient line of nonvolatile RAMs

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by Susan Nordyk @ edn.com:

Cypress Semiconductor is sampling a 4-Mbit ferroelectric RAM (F-RAM), which is one of the industry’s highest density serial F-RAMs, featuring a 40-MHz serial peripheral interface (SPI) and a 2.0-V to 3.6-V operating voltage range. F-RAMs consume 200 times less energy than serial EEPROMs and 3000 times less energy than NOR flash devices. Further, Cypress F-RAMs are able to endure 100 trillion read/write cycles and provide 10-year data retention at 85°C and 151 years at 65°C.

These energy-efficient memory devices are useful for applications requiring continuous and frequent high-speed reading and writing of data with absolute data security. The 4-Mbit F-RAM devices address mission-critical applications, such as industrial controls and automation, industrial metering, multifunction printers, test and measurement equipment, and medical wearables.

Cypress expands energy-efficient line of nonvolatile RAMs – [Link]

A signal amplifier module for HF

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Marcus Jenkins blogged about his radio frequency amplifier project:

In building QRP HF radios, having an RF signal level amplifier building block is handy. You want 50 Ohm output impedance, some reasonable gain, supply voltage of the usual 10-14V and ease of building using standard parts from your parts bin. Some searching around the interwebs came up with a good idea for circuit from Aaron Parks, KC8FQD, who did a YouTube video on a WWV receiver.

A signal amplifier module for HF – [Link]

Arduino time lapse – camera pan device

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An Arduino camera pan device project from Bajdi Electronics:

I own one of these small action cameras (SJcam SJ4000). I bought it because it’s small, and easy to take with you wherever you go. To make nice stable videos I mount it on a mini tripod. This got me thinking that it would be fun to have a little motor between the tripod and the camera to slowly pan the camera. That way I can make nice time lapse videos.
I happened to have a couple of 24byj48 stepper motors laying around, these little steppers motors have a gearbox and are 4096 steps for one rotation. They are pretty slow, so it’s ideal for this application. These motors are sold with a driver board that is basically an ULN2003 break out board.

Arduino time lapse – camera pan device – [Link]

RELATED POSTS

Mini weather station with Attiny85

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by diy_bloke @ instructables.com:

In a recent instructable Indigod0g described a mini weather station that works pretty well, using two Arduinos. Maybe not everyone wants to sacrifice 2 Arduinos to get humidity and temperature readings and I commented that it should be possible to do a similar function with two Attiny85’s. I guess talk is easy, so I better put my money where my mouth is.

Mini weather station with Attiny85 – [Link]

Samsung gets serious about the IoT

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by elektormagazine.com:

At the ‘Internet of Things World’ event held in San Francisco, Samsung Electronics announced three boards making up their new ARTIK development platform targeted at the Internet of Things (IoT) applications. To make the platform more attractive for developers it is compatible with the existing Arduino software development system. Young Sohn, President and Chief Strategy Officer of Samsung Electronics and Massimo Banzi, Co-founder of Arduino shared the stage to make the announcement.

The ARTIK 1 at 12mm square is the smallest board and includes a Dual Core processor running at 250 MHz and 80 MHz with 1 MB on-chip and 4 MB SPI Flash memory together with Bluetooth Low Energy (BLE) with Chip Antenna, secure element to give HW security and a 9-axis motion sensor. A single charge will allow the board to operate for three weeks while always-on and paired with a smartphone.

Samsung gets serious about the IoT – [Link]

xPico WiFi SMT doesn’t require connector neither antenna

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High mechanical stability is one of benefits of a new „SMT“ version of the popular Lantronix xPico WiFi module.

Lantronix xPico WiFi module may be already familiar to you from our articles, for example: xPico WiFi is a dream come true for producers and customers where we also mention the HW compatibility with the xPico module ( wired, serial-to-Ethernet modul). New version – xPico WiFi SMT brings the same functionality as xPico WiFi and as the name saysm it´s intended for a direct soldering by an SMT (reflow) process, together with other components on a PCB. In contrast to original version which has an SMT (board-to-board) connector, SMT version is designed similarly like many GSM/GPS modules, i.e. as a module on a carrying PCB with soldering pads on PCB sides (half-vias, plus gnd on a bottom).

At the same time, SMT version is also available with integrated small ceramic antenna, so no external antenna is required. Just this version XPCW1003100B we keep as a standard stock item. Perhaps the biggest advantage of SMT version is this possibility of a direct soldering bringing a very high mechanical stability – also suitable for applications with a higher risk of vibrations.

xPico WiFi SMT is the same powerful („device server“) as a previous version and offers easiest way how to add WiFi connectivity into a target device, practically without a necessity to write a single line of code.

Simultaneous AP (Access Point) with a DHCP server and Client mode also enable a direct access – communication with other WiFi device, for example with a tablet or a smartphone.

Detailed information will provide you the xPico WiFi SMT brochure, xPico WiFi SMTi datasheet and the xPico WiFi SMT integration guide.


xPico WiFi SMT doesn’t require connector neither antenna – [Link]