Many homes in the United States have water that contains higher concentrations of dissolved minerals, which is called hard water. Although there is nothing toxic about hard water, it is less desirable for cleaning, it leaves mineral deposits, and it can shorten the lifetime or efficiency of equipment such as water heaters.
A water softener is a household appliance that commonly exchanges salt for some of the dissolved minerals, resulting in softer water. The salt supply is stored in a brine tank and must be refilled every month or so. If you forget to refill the tank, the water softener is rendered temporarily ineffective.
Water Softener LED Display - [Link]
by deba168 @ instructables.com:
One year ago, I began building my own solar system to provide power for my village house.Initially I made a LM317 based charge controller and an Energy meter for monitoring the system.Finally I made PWM charge controller.In April-2014 I posted my PWM solar charge controller designs on the web,it became very popular. Lots of people all over the world have built their own. So many students have made it for their college project by taking help from me.I got several mails every day from people with questions regarding hardware and software modification for different rated solar panel and battery. A very large percentage of the emails are regarding the modification of charge controller for a 12Volt solar system.
Arduino solar charge controller and energy monitor - [Link]
by EEVblog @ youtube.com:
In this tutorial Dave demonstrates the seldom used and often little understood mathematical integration function available on your modern digital oscilloscope. And demonstrates a practical example use for it in accurately measuring the total power consumption of a microcontroller that sleeps and then wakes up and does some processing before shutting down again. By getting the total area under the current curve.
EEVblog #662- How & Why to use Integration on an Oscilloscope - [Link]
by EEVblog @ youtube.com:
Dave shows you how to reverse engineer a PCB to get the schematic. In this case the new Rigol DS1054Z oscilloscope.
How does the discrete transistor analog front end and the software bandwidth limiting work?
How do you decode SMD transistor codes?
How does it compare to the old Rigol DS1052E?
Dave also discusses the low voltage ohms function of a mulitmeter, how it’s useful, and how to test your multimeter to see if it will have any issues with in-circuit testing.
EEVblog #675 – How To Reverse Engineer A Rigol DS1054Z - [Link]
by Philippe Duboisset:
This project is an open source (hardware & software) DDS generator, based on: smart TFT module, AD9834, LM7171 fast amplifier. The homemade function generator is a quite common project on the internet. We can find different ways to do it:
– The quick & dirty way based on a DDS module bought on eBay
– The analog version based on a MAX038 / XR2206
– The clean way based on a FPGA and a fast DAC (e.g. http://www.circuitben.net/node/14)
– The software way (e.g. Arduino + R/2R DAC)
From my side, I wanted a small one which could fits my needs without being too expensive. According to me, such generator should at least:
– Be easy to use
– Output a signal from 1Vpp to 10Vpp (+/-5V), from 0 to 1MHz
– Have a low profile
– Without electric hazard (shall work on a 12V DC)
Tiny DDS – Open source DDS generator - [Link]
This Application Note from Microchip provides a reference design for building a non-invasive blood pressure meter using the PIC24FJ128GC010 microcontroller and MCP6N11 instrumentation amplifier. [via]
A digital blood pressure meter measures systolic and diastolic pressures by oscillometric detection. Microchip’s digital blood pressure meter demo can measure blood pressure and pulse rate during inflation. The Measurement While Inflating (MWI) principle reduces overall measuring time, which in turn reduces discomfort caused by the pressure in the cuff.
Digital blood pressure meter design using PIC microcontroller - [Link]
by ajoyraman @ instructables.com:
USB connected TI TMS320F28027 based ZRLC Tweezers with
Most Digital multi-meters measure Resistance and Capacitance and LC-meters can measure Inductance and Capacitance. Presented here is a ZRLC meter which can measure Resistance, Capacitance, Inductance and Complex Impedance.
The hardware is built around a TMS320F28027 micro-controller an 8-port-analog-switch ADG714 from analog-devices and a Microchip rail-to-rail dual operational-amplifier MCP6022.
USB Tweezers for ZRLC measurements - [Link]
ajoyraman posted a tutorial on how to make a DIY USB-matchbox oscilloscope, an instructable here:
In order to economize on the cost of an enclosure while still providing an aesthetic unit the Aj_Scope2 is enclosed in a large size cardboard matchbox enclosure.
The USB connection to the PC is on one end while the Audio-Jack for the signals to be monitored is on the other.
A ‘Busy’ LED is provided on one corner at the top and a ‘Reset’ switch is provided diagonally opposite.
The ‘Reset’ switch provides a restart of the micro-controller is the worst-case of hang-up. This typically occurs when the operator selects a trigger threshold which is out of limits with respect to the waveform being observed. If the Aj_Scope2 is operated correctly this switch is seldom used.
DIY USB-Oscilloscope in a matchbox - [Link]
by Glen Chenier @ edn.com:
What I asked for was a general purpose 5GSa/s 1GHz four-channel bench scope. What I got was a 1GSa/s 100MHz two-channel. Still, it is somewhat usable, and less expensive than a fancy temperature-controlled soldering station. But it has bugs – many bugs.
I have been negotiating with the manufacturer to get a firmware update to fix these bugs. After five months, no results. This scope has been designed to accept firmware updates. Good planning. It needs them – desperately. (“Ship now and fix the bugs later. We have a schedule to keep!”)
Before listing all the functional problems, let me elaborate on what I actually like about this scope. The advertised bandwidth is 100MHz, but when feeding in a 300ps edge (ECL directly into the scope with a BNC-T 50 ohm terminator), the measured scope risetime indicates the bandwidth is more like 140MHz. Hurrah for the analog designers!
The scope…from Hell! - [Link]
The LTC2946 is a high or low side charge, power and energy monitor for DC supply rails in the 0V to 100V range. An integrated ±0.4% accurate, 12-bit ADC and external precision time base (crystal or clock) enables measurement accuracy better than ±0.6% for current and charge, and ±1% for power and energy. A ±5% accurate internal time base substitutes in the absence of an external one. All digital readings, including minimums and maximums of voltage, current and power, are stored in registers accessible by an I²C/SMBus interface. The part’s wide operating range makes it ideal for monitoring board energy consumption in blade servers, telecom, solar and industrial equipment, and advanced mezzanine cards (AMC).
LTC2946 – Wide Range I2C Power, Charge and Energy Monitor - [Link]