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Liquid or Air Pressure Switch with Relay

This pressure switch project is built using a piezoresistive transducer, LM358 OPAMP as comparator, and a relay. The circuit activate the relay when the pressure in a system exceed a given set-point. Basically, this switch can power ON or OFF a pump, valve, motor, when certain pressure is reached. A trimmer potentiometer is provided to set the trigger point. LM358 is used as comparator, relay has Normally Open/Normally closed contacts with current rating 5Amps @ 230V AC or 10Amps @ 28V DC. LM78L05 IC is used to provide 5V DC supply to pressure sensor. Operating voltage of this circuit is 12V and it consumes approx. 40mA current when Relay is in ON condition. We have used MPXV5010DP pressure sensor from NXP. This is an analog pressure sensor and the output of this sensor is 0.2V to 4.7V which is proportional to the applied pressure range of 0-10kPa (0 to 1.75PSI).

Possible application of this switch is, industrial pumps, small compressor, low pressure vacuum pump, medical equipment, appliance liquid level and pressure measurement.

One of the great uses of this switch, is to measure the liquid level in tank and trigger a PUMP or Valve at set point. Measuring the range of a liquid in tank is 0 to 100 cm and this corresponds to a pressure range of 0 to 10kPa. See the setup diagram below on ow to use the board as water level on/off switch.

The MPXV5010DP series piezoresistive transducers are state-of-the-art monolithic silicon pressure sensors designed for a wide range of applications, but particularly those employing a microcontroller or microprocessor with A/D inputs. This transducer combines advanced micromachining techniques, thin-film metallization, and bipolar processing to provide an accurate, high level analog output signal that is proportional to the applied pressure. The axial port has been modified to accommodate industrial grade tubing.

Features

Operating Supply 12V DC
Maximum Current Consumption 40mA
Switch trigger relay when pressure 0 to 10kPa applied
Switch Can work with Air pressure or Liquid level
Relay Output is NO/NC
Relay Switch 5Amps 230V AC or 10Amps 28V DC
PCB dimensions: 66.68 x 26.67 mm

Schematic

Parts List

Connections

Gerber View

Test Setup

Photos

Video

MPXV5010DP Datasheet

PWM Module with Dual Source/Sink Outputs using SG3525

SG3525 PWM module is a great tool for every hobbyist. This circuit can be used in various applications such as switching power supply, DC-DC converter, DC motor speed controller, LED dimer, High voltage power supply, solenoid driver, and electronic DC load. This low-cost pulse width modulator control circuit offers improved performance. The circuit has various options such as adjustable PWM, adjustable frequency, optional soft start, dual source/sink output with 50% duty cycle, single output with 0 to 100% duty cycle and output signal voltage level TTL-5V or 12V selection using a jumper. The 5V PWM signal is rated at low current hence don’t draw more than 20mA. The 12V outputs are capable to drive a MOSFET directly.

This module also has the feature of dual source/sink outputs. The output stages are totem-pole design capable of sinking and sourcing in excess of 200mA. The output stage of the SG3525A features NOR logic resulting in a low output for an off−state, both outputs are capable to drive the gate of a MOSFET. Open the jumpers J2 and J3 to set the module for source/sink mode. In this mode output frequency is 105Hz to 3.2Khz. Use R2 10 Ohms for source and sink mode.

Note: This IC is capable to work at frequency 100 Hz to 400Khz. Output frequency span is dependent on capacitor C3 value, we have used 0.1uF capacitor which set the frequency 215Hz to 6.5Khz, by changing capacitor value to 0.01uF frequency range would change to 2.2Khz to 65Khz.

Features

Supply 12V DC (8-12V)
Frequency 215Hz to 6.5Khz (Single Output Mode)
Duty Cycle 0 to 100%
Frequency 105 Hz to 3.2Khz Dual output Source/Sink
Duty Cycle Dual mode 0 to 50%
Soft start Optional (Mount C2 10/16V Capacitor for Soft start)
On Board Power LED
PCB Dimensions 29.85X 15.88 mm

Single Output (0 to 100% Duty Cycle)

Close Jumper J2 and J3
Trimmer Potentiometer P1 Duty Cycle Adjust 0 to 100%
Trimmer Potentiometer PR1 Frequency Adjust 215Hz to 6.5Khz
Jumper J1 output voltage level selection 5V or 12V
If soft start required: Mount C2 10uF/16V for soft start or Omit for normal operation
CN1 Pin 4-PW and GND provides output

Dual Outputs ( 0 to 50% Duty Cycle)

Open Jumper J2 and J3
Trimmer Potentiometer P1 Duty Cycle Adjust 0 to 50%
Trimmer Potentiometer PR1 Frequency Adjust 105Hz to 3.2Khz
Jumper J1 output voltage level selection 5V or 12V
If soft start required: Mount C2 10uF/16V for soft start or Omit for normal operation
CN1 Pin 3 OPB and Pin 5 OPA dual source Sink outputs

Schematic

Parts List

Connections

Gerber View

Photos

Video

SG3525 Datasheet

e-peas Releases AEM10941 Power Management IC for battery-less Monitoring Hardware

Posted on 18 November, 2020 by mixos

e-peas announced its AEM10941 power management IC (PMIC) has been designed into battery-less monitoring hardware from Xeelas.

The PMIC is optimized for photovoltaic-based energy harvesting deployments, covering 50mV to 5V input voltage range with power up of just 3µW input. Further, it delivers two voltage-regulated outputs of 1.2-1.8V and 1.8V-4.1V.

Xeelas’ Series S gateway, which includes the PMIC, was built for the acquisition of periodic data on the operational status of non-powered assets in remote locations. The gateways also have two solar panels which may be used as GPS antennas for accurate location fix.

Per the company, the cellular IoT plus GSM connectivity allow data transmission, as well as over-the-air updates.

For more information, visit https://xeelas.nl or www.e-peas.com

STMicroelectronics TSC213 current sense amplifiers

Posted on 18 November, 2020 by mixos

TSC213 is a zero-drift current sense amplifier that can sense current via a shunt resistor over a wide range of common-mode voltages from -0.3 to +26 V, whatever the supply voltage is

TSC213 is a zero-drift current sense amplifier that can sense current via a shunt resistor over a wide range of common-mode voltages from -0.3 to +26 V, whatever the supply voltage is. The TSC213 is designed with a specific zero-drift architecture, which can achieve high precision. TSC213 is a current sense amplifier that may be used in various functions such as precision current measurement, over current protection, current monitoring, feedback loops. It fully operates over the broad supply voltage range of 2.7 to 26 V and over the industrial temperature range -40 to 125 °C.

Key features

Wide common mode voltage: -0.3 to 26 V
2.7 to 26 V supply voltage
Gain of 50 V/V
Offset voltage: ±100 µV max.

Additional features

Wide common-mode voltage: -0.3 to 26 V
Offset voltage: ±100 µV max.
2.7 to 26 V supply voltage
Gain available (50 V/V)
Gain error: ±1% max.
Offset drift: 0.1 µV/°C max.
Gain drift: 20 ppm/°C max.
Quiescent current: 100 µA
QFN10 (1.8 x 1.4 mm) and SC70-6

more information: https://www.st.com/en/amplifiers-and-comparators/tsc213.html

LD49100 Low Quiescent Voltage Regulator

Posted on 18 November, 2020 by mixos

STMicroelectronics’ voltage regulators are stable with ceramic capacitors on the input and output

STMicroelectronics’ LD49100 provides 1 A maximum current with an input voltage range from 1.5 V to 5.5 V and a typical dropout voltage of 200 mV at 1 A output current. The device is stable with ceramic capacitors on the input and output.

The ultra low-dropout voltage, low quiescent current and low-noise features make it suitable for a wide range of automotive applications. Power supply rejection is 70 dB at low frequency and starts to roll off at 10 kHz. Enable logic control function puts the LD49100 in shutdown mode, allowing a total current consumption lower than 1 μA.

AEC-Q100 qualified
Temperature range: -40°C to +125°C
Input voltage from 1.5 V to 5.5 V
Ultra low-dropout voltage (200 mV typ. at 1 A load)
Very low quiescent current (20 µA typ. at no load)
Very low-noise with no bypass capacitor (30 µV_RMS at V_OUT = 0.8 V)
Output voltage tolerance: ±2.0%
DFN6 (3 mm x 3 mm) package with wettable flanks

more information: https://www.st.com/en/power-management/ld49100.html

Vecow SPC-7000/7100 – Compact and Fanless Tiger Lake UP3 Embedded Box PC for AI-related Applications

Posted on 18 November, 202018 November, 2020 by Emmanuel Odunlade

Barely a month after Vecow introduced the SPC-6000 fanless embedded PC powered by an Atom x6425RE Elkhart Lake processor, the company is back to announce another ultra-compact fanless embedded box PC aimed at delivering powerful computing performance and outstanding graphics to meet the demands of the fast-growing AI-related applications.

Vecow SPC-7000/7100 box PC is powered by the latest 11th Gen Intel® Core™ i7/i5/i3 processor (Tiger Lake UP3) that supports up to 32GB DDR4 3200HMz memory and between 12W and 28W TDP. It also features the Intel® Iris® Xe Graphics that supports dual simultaneous and independent displays up to 8K resolution, alongside a 9V to 55V DC-in power input, optional full function SUMIT A, B expansion, one 2.5GbE LAN and TSN networking, which make it perfect for factory automation, service robot, cellular V2X, smart retail, Industry 4.0 and AIoT applications.

The SPC-7000 is exactly the same as the SPC-7100 but the company added fins to the metal top cover of the SPC-7100 for extra cooling; the reason for the difference in dimensions, weight and temperature range.

Features and Specifications of the Vecow SPC-7000/7100 include:

11th Gen Intel® Core i7/i5/i3 quad-core (Tiger Lake UP3) processor with 12W to 28W configurable TDP
Intel UHD graphics or Intel Iris Xe Graphics for discrete-level graphics performance, supports DirectX 12, OpenGL 4.6, OpenCL 2.0, and max 8K resolution
Up to 32GB 3200MHz DDR4 SO-DIMM memory
1x M.2 Key B 2260 Socket
1x SATA III (6Gbps)
SPI flash for AMI BIOS
1x GbE via Intel Ethernet Controller I219LM with support for iAMT (Intel Active Management Technology), Wake on LAN, PXE
1x 2.5 GbE via Intel Ethernet Network Connection GPY215
WiFi 5/6 or/and 4G/5G cellular with Nano SIM card slot
Dual DisplayPort outputs up to 4096 x 2304 @ 60Hz
2x USB 3.1 Type-A ports (10Gbps)
2x USB 2.0 Type-A ports
2x USB 2.0 via internal header
2x COM RS-232/422/485
1x M.2 Key B 3042/3052 Socket
1x M.2 Key E 2230 Socket
2x Stackable Unified Module Interconnect Technology A/B slots with customized chassis (optional)
Infineon SLB9670 TPM 2.0, SPI Interface
3.5mm Mic-in jack, 3.5mm Line-out jack
Realtek ALC892 audio codec, 5.1 Channel HD Audio
Optional DIN Rail and VESA mounts.
Power, HDD, WWAN and WLAN LEDs
ITE IT8786E Embedded Controller
16 mode ignition control
2-pin remote switch
Watchdog timer, and,
9V to 55V wide range DC Power input, via 3-pin terminal block with V+, V-, and GND
Operating System: Windows 10 or Linux
Dimensions:
- Vecow SPC-7000 – 150.4 mm x 106.2mm x 48.1mm
- Vecow SPC-7100 – 150.4 mm x 106.2x 62.1mm
Weight:
- Vecow SPC-7100 – 0.9 kg
- Vecow SPC-7100 – 1.3 kg
Temperature Range:
- Vecow SPC-7000 – -40°C to 70°C (operating); -40°C to 85°C (storage)
- Vecow SPC-7100 – -40°C to 85°C (operating and storage)
Humidity: 5% – 95%
EMC: CE, FCC EN50155, EN50121-3-2

The company has not said anything on price or availability of the hardware yet, but you can visit the product page if you’d like to make further inquiry about the rugged computers.

Oscilloscope Tester Keyring (OTK) can test your oscilloscope

Posted on 18 November, 2020 by Tope Oluyemi

The Engineering Octopus has launched a keyring which helps you keep track of your keys, and also serves as a means to quickly test an oscilloscope. It is called the Oscilloscope Tester Keyring (OTK). About the inspiration for the project, Max the brain behind the OTK says

“All electronic engineers love to show off the fact that they’re electronic engineers, and what better way to do that than with a keyring! Not only will the bare electronics be noticed by many, it’s also a functional tester!” He continues “I made it because I wanted a tool I could take with me, to easily test oscilloscopes when I go and view them. Often, they don’t have the probes or any means of testing. Plus, I really wanted a cool electronic key ring, and I couldn’t find one!”

The OTK works by generating a pure sine wave (via a Colpitts resonant oscillator) at a particular frequency (current models generate either approx. 10MHz, 20MHz, 50MHz) which is ideally close to the bandwidth of the scope. It features a DC offset, which enables you to test almost all functions of the ‘scope, and carry it with you everywhere you go! It’s battery powered (not included) via a 2032 / watch battery. It also features a micro USB port so that you can use the oscilloscopes (or power banks) USB port for power.

About the scope, he says “

But my ‘scope has a square wave function, I hear you cry? Indeed, this is true, but firstly it doesn’t fit on a key ring / look cool, and secondly, you need probes to test it! Where the OTK really shines, is for those of you who love to repair / buy ‘scopes. More often than not, they’re not supplied with probes, and this is a quick and easy tool that can be taken with you to viewings. You simply plug it into the BNC connector, and test it out!”

Application of the OTK includes:

DC / AC / GND switch test
CRT Intensity
Horizontal / vertical positioning
Time base issues
Volts per division issues
Single Shot
Triggering issues

You can also apply it to a host of other things if you’re creative. However, we should note that the Oscilloscope Tester Keyring©, also referred to as OTK, is not designed as a substitute for reference testing, and is designed as a quick initial check of an oscilloscope, or similar equipment. The sine wave generated is approximately at the stated frequency of 10MHz.

It is not advised to keep the battery installed whilst the OTK is worn on a keyring, with keys. This is due to the potential shorting of the battery due to metallic keys. However, if this does occur, it is unlikely to cause any issues. “The products have been cleaned with IPA and Flux-OFF, while every effort has been made to ensure no residue of either remains, it may be possible that some is left. Please ensure suitable handling.” The OTK is available from The Engineering Octopus priced at £8.50 or via Tindie for $10.99.

New Digit Benchtop Multimeters with Simple to Read 4.3-inch LCD

Posted on 17 November, 2020 by mixos

B&K Precision Launches New Multimeters Available in 5 1/2 and 6 1/2-Digit Models

The 5490C Series offers fast measurement speeds, graphical display features, and extensive measurement functions for a wide range of applications

B&K Precision, a leading designer and manufacturer of reliable, cost-effective test and measurement instruments, today announces a new generation of 5 ½ and 6 ½-digit benchtop multimeters designed for accuracy, repeatability and ease-of-use. Both 5492C (5 ½) and 5493C (6 ½) models deliver measurement speeds up to 1000 readings per second and support 12 measurement functions while the 6 ½-digit model provides greater accuracy, higher resolution, and rear input terminals to simplify connections.

Features:

12 measurement functions: DCV, ACV, DCI, ACI, 2 and 4-wire resistance, capacitance, frequency, diode, temperature, continuity test, DCV ratio
High-contrast 4.3-inch full color LCD
Measurement speed up to 1000 readings/s
DCV basic accuracy up to 35 ppm (0.0035%)
Histogram, bar graph, trend chart, and numeric display options
Display Min, Max, Peak-to-Peak, Average, Standard Deviation statistics simultaneously
Null, dB, dBm, %, mx+b, and run/stop math functions
AC frequency measurements to 1MHz
Internal storage buffer for up to 10,000 readings
2 and 4-wire resistance measurements down to 10 Ω
Dual measurement display
Rear input terminals for rack use (6 ½-digit model only)
Standard USB (USBTMC-compliant), LAN, and RS232 interfaces, supporting SCPI commands. GPIB option
Front panel USB host port to export measurements, screen captures and save/recall settings
LabVIEW^TM driver and operating software for remote instrument control, measurement monitoring, and data logging included

The easy to read 4.3-inch LCD offers a variety of measurement display modes including numeric, bar meter, trend chart, and histogram. Other built-in functions include Limit mode to quickly verify measurements are within a user-defined range, Probe hold mode to capture a sequence of stable readings, and dual measurement capabilities.

The 5490C Series provides USB (USBTMC-compliant), LAN, and RS232 interfaces standard with GPIB optional. The included operating software supports remote instrument control, measurement, monitoring, and data logging. A LabVIEWTM driver is available for download to help simplify system integration and instrument control.

Available now, this series starts at $780 and is backed by a 3-year standard warranty.

For additional technical specification, accessories, photos, and support documents, visit: https://www.bkprecision.com/products/multimeters/5492C-5-1-2-bench-digital-multimeter.html

NanoPi R4S Headless SBC Supports Up To 4GB RAM and Features Dual Gigabit Ethernet and USB 3.0 Ports

Posted on 17 November, 202017 November, 2020 by Emmanuel Odunlade

FriendlyELEC is currently working on new RK3399 SoC based single board computer called NanoPi R4S. The company has not officially announced the board yet but it’s existence was discovered by CNX software who came across a “hidden page” where the board was extensively talked about.

Unlike other headless SBCs that we have come across over the years like the Orange Pi Zero Plus or NanoPi R2S which are usually based on 32-bit Cortex-A7 or low power 64-bit Cortex-A53 processors coupled with up to 512MB to 2GB, the new NanoPi R4S headless SBC is powered by a Rockchip RK3399 hexa-core Cortex-A72/A53 processor and has up to 4GB RAM system memory. The NanoPi R4S also comes with two USB 3.0 ports and a dual Gigabit Ethernet, meaning you can connect it to your home or work network and use it as a headless computer.

Some of the key features and specifications of the NanoPi R4S headless SBC include:

Rockchip RK3399 hexa-core processor; dual-Core Cortex-A72 (up to 2.0GHz) and quad-core Cortex-A53 (up to 1.5GHz)
Mali-T864 GPU with OpenGL ES1.1/2.0/3.0/3.1, OpenCL, DX11, and AFBC support
4K VP9 and 4K 10-bit H265/H264 60fps video decoder
1GB DDR3 or 4GB LPDDR4
1x MicroSD card slot
Dual GbE; one native Gigabit Ethernet and one PCIe Gigabit Ethernet
2x USB 3.0 Type-A ports, USB 2.0 via 4-pin header
2x 5-pin header with 1x SPI, 1x I2C
1x 3-pin debug UART header
1x power LED, and 3x user LEDs (SYS, LAN, WAN)
1x User button
2-pin 1.25mm RTC battery connector
1x 5V fan connector
5V/3A power supply via pin header or USB-C connector
RK808-D PMIC along with independent DC/DC, enabling DVFS, software power-down, RTC wake-up, system sleep mode
Dimension: 66 mm x 66 mm
Operating Temperature Range: -20°C to 70°C

Note that the NanoPi R4S headless SBC cannot be plugged it into a TV or monitor as a media center or desktop computer because it doesn’t have a video out port.

There’s no information about the operating system, but judging from the trend with past RK3399 products, the company should offer both Ubuntu and OpenWrt images. We also don’t know what the price of the NanoPi R4S headless SBC would be yet, but we can tell it wouldn’t cost much, judging too from the prices of the NanoPi M4 SBC that cost around $30-$35 for 1GB RAM model and $60-$65 for 4GB RAM model.

The company is yet to upload details of the SBC on their wiki page, but you can find more about the board including schematics and CAD files for both the 1GB and 4GB RAM, here.

Penguino Feather 4260 SAMR34 based LoRa Dev-Board Features RAK4260 module

Posted on 17 November, 2020 by Tope Oluyemi

MakerTronika Labs has launched their Feather compatible board with LoRa connectivity called Penguino Feather 4260. The Penguino Feather is a SAMR34 based LoRa/LoRaWAN™ dev-board with all the necessary components for fast prototyping. It’s a successor of my previous Penguino SAMR34 design. The new design uses the RAK4260 module from RAKWireless and improves on some aspects, such as a USB Type-C, a RGB LED, a user button, battery protection & voltage supervision, and optional flash & per-provisioned secure element IC pads. Regarding why the board was made, they say:

“The official eval board from RAKwireless is not designed to be low power board. Moreover, it uses proprietary WisBLOCK connectors to add extra sensors and there aren’t many readily available sensors with that connector. Adafruit Feather style however, is more breadboard friendly and there are many suitable add-on boards (Feather Wings) to choose from.”

The board can be integrated into a portable, battery-powered IoT device for solving real-world problems.

The board can be flashed using an ATMEL-ICE or a J-Link SWD programmer/debugger. You can choose to carry out software development either with the officially supported Atmel Studio v7 (ASF) or the unofficial Arduino port for a similar board from Electronic Cats. You can also find a Platform.IO port of Atmel Software Framework for SAMR34 with many examples, which works perfectly fine. MakerTronika Labs has also released an installation guide to correctly setup the ASF v3 (Atmel-Software-Framework) for those who plan to use Atmel Studio 7. However, ASF v4 with ATMEL START is currently not supported for SAMR34 devices.

Serial communication with the board can be established either over the Rx-Tx pins using USB to Serial converter or with the on-board USB. To activate the on-board USB as Virtual COM Port (VCP), you have to use Atmel USB Device CDC Application example provided by the ASF. There are several VCP example projects with and without the LoRaWAN stack. The board doesn’t come with a case, but you can get one from Thingiverse. The company says If you really want one, you should indicate it during the checkout and they can include one in the package.

Specifications include:

ATSAMR34J18 LoRA™ System-in-Package (SiP) based RAK4260 module
ARM Cortex M0+ MCU & SX1276 LoRa Radio
256KB Flash, 40 KB RAM
32MHz TXCO
Max Tx Power: +20 dBm; Max Sensitivity: -148dBm; Rx Current: 17mA (typical)
Frequency Range: 862 to 1020 MHz
Deep Sleep Current: ~1 μA (RF module only)
Li-Po battery charging IC
CH340E USB-to-UART converter IC (with solder jumpers between native USB and UART lines)
RGB user LED, Battery Charge Status (red) and Power (blue) (w/ cut-off jumpers)
3.3V low Iq LDO (~1 μA)
Low-voltage battery cut-off supervisor IC (3V Vbat cutoff)
USB Type-C connector with protection/filtering circuit
0.75 A resettable fuse
Voltage divider for Vbat monitoring (w/ cut-off jumpers)
SMA and u.FL (iPEX) antenna connectors
10-pin SWD programming header
Dimensions: 2 in. x 0.9 in. (50.8 mm x 22.8 mm)

Penguino Feather 4260 LoRa board is available for $39.95 plus shipping on Tindie with an external antenna. The project is open-source hardware, so KiCad schematics, PCB layout, Gerber files, BoM, and firmware can be found on Github under CERN-OHL-S v2 (hardware) or MIT (software) license.