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13
votes
9answers
27k views

Arduino with assembly?

For my venture into microprocessing, I decided to go with Atmel AVR due to the vast resources available. The Arduino seems to have a lot as well, not to mention their starter kits seem more "at ...
4
votes
6answers
3k views

Graphical equivalent to HD44780 LCD controller

The Hitachi HD44780 LCD controller is an extremely common character-mode LCD controller. Though I believe it is now discontinued, compatible controllers are used in many hobbyist and commercial grade ...
2
votes
2answers
2k views

Balancing Unbalanced Audio Inputs

I'm wanting to nicely balance some unbalanced inputs to a power amp for good CMRR, and because I'm feeling too lazy to start trying to closely match pairs of resistors, I'm looking at using a hi-fi ...
4
votes
1answer
402 views

How do I determine the fastest time between pulses I can measure?

I need to calculate the elapsed time between the rising edge of one pulse to the rising edge of the next pulse. This needs to be in a mobile environment, but I am not attached to any solution as long ...
7
votes
3answers
648 views

Acoustic Measurement of water level

Is it possible to measure the amount of water in a rubber water tank by using sound waves? I want to make a non intrusive measuring device that attaches to the outside of a tank, and is able to ...
5
votes
2answers
3k views

is it possible to repair a DMM which was burned by putting the leads into 230V on a frequency-measuring setting?

There is a DMM (not a cheap one, so its worth to repair it), whose leads where put into a 230V AC socket on the frequency measuring range. The meter did "bzzzt" sound and stopped showing anything. ...
3
votes
2answers
3k views

Where to place decoupling capacitor

I am using this(also below in question) circuit to drive a motor, and I heard I should put a decoupling cap in there to smooth out voltage spikes. I have been told to put it close to the ic, and I ...
3
votes
3answers
3k views

Verilog simulator or development environment on Mac OS

Is there a way to develop some Verilog designs on mac?
2
votes
2answers
744 views

Voltage Divider

I need to cut the voltage going through a 1/4" TRS cable (at the connector) by 1/2 (and I need to do this to about 14 cables). I understand that this can be accomplished with two 4.7 kohm resistors ...
3
votes
2answers
2k views

Driving a LED Matrix with a N-channel MOSFET (2N3819) using an AVR

I am trying to wire up a LED matrix using a FET transistor as a switch. The AVR will be connected to the gate. To turn the LEDs on I have drive the pin connected to the transistor gate low, right?
2
votes
1answer
885 views

Writing to timer counter while timer is running

I'm using PIC16F1947 for a project. The project requires real time tracking so a stable 32768 Hz crystal is connected with the Timer1 oscillator. The Timer1 oscillator circuit and the crystal will ...
2
votes
1answer
856 views

Complementary Code Keying

Asked the question here : I would like to understand Complementary Code Keying. How modulation and demodulation is done ? How higher data rate is achieved using CCK modulation in IEEE 802.11b ? ...
2
votes
2answers
201 views

Low energy arithmetic/logic gate level design

I'm looking into various gate level (NAND, NOR, AND, INV) designs for low energy arithmetic/logic blocks, especially adders. Low energy indicates the use of minimal energy per operation executed. ...
1
vote
2answers
474 views

Electrified Vertical mounted rotary joint questions

Hey all, continuing my PhotoBioReactor project. :) Need some assistance determining not only what kind of rotary slip ring I need to use but where to get it as well. Basic overview: I plan on ...
1
vote
4answers
2k views

Using a DVD diode to create a mag-lite laser

So, I decided I wanted to make my very first foray into some basic electronics. I decided I was going to attempt to make a laser mag-lite, as per this hack here. The steps seem pretty straight forward,...
3
votes
2answers
775 views

What probems may arise with a 200V rated relay conducting 1000V 1A?

I am going to use a DPST relay to pass a 1A 1000V DC signal of an ESD Human Body Model simulator circuit through it. I have see many relays, they share a property like maximum DC switching for ...
4
votes
2answers
2k views

Best way to measure 230VAC

I'm trying to design a circuit to measure power of 230VAC (MAINS), with the ADC of a small MCU. I have designed the part of the circuit to measure current, but my solution to measure voltage is ...
12
votes
3answers
8k views

How to discharge smoothing capacitors?

I have a simple 12V 10 A power supply with just a transformer and a rectifier. After doing some research and simulations, I've added 3 10 mF capacitors in parallel to smooth out the output. My ...
1
vote
1answer
2k views

How to set ATmega88PA fuses in code or HEX file

I'm a Microchip guy, but I'm helping a customer out with an Atmel project using the ATmega88PA project they inherited from another division. I'm using AVR Studio 5 and I would like to compile the fuse ...
2
votes
2answers
3k views

Video & image processing in Spartan-6 FPGA

I'm very new to FPGA. I got a Spartan-6 from Digilent. As my final year project I want to do image processing through it. How can MATLAB & Simulink be used for this? How should the camera be ...
8
votes
7answers
53k views

How do I find the maximum “discharge C rating” of a battery?

I've been experimenting running my 3A LED strips off battery power and the results are disappointing. I'm only getting a few minutes (< 10) out of a YSD-168 1800mAh lithium ion. How can I find the "...
2
votes
3answers
973 views

Beginner question regarding batteries' voltage/amperage

I want to use two batteries rated 6v, 4A with a 9v,1A device. I figured that connecting the batteries in parallel would give 12v and connecting a 3ohm resistor in series with the device would give the ...
6
votes
1answer
1k views

connect my rc car controller with my computer

I am new to hardware. For my first project, I want to connect my RC car controller with my computer so I can control my RC car in my PC. What kind of things (hardware, cables, tools, as well as ...
1
vote
2answers
2k views

Need oscillating servo/stepper motor guidance

EDIT: Additional Information below original post... Looking for a 360 degree servo motor that has adjustable control for timing of steps (or at the least timing per full oscillation) and can support (...
1
vote
2answers
469 views

When to Use a Etched Prototyping PCB vs. Custom-Patterned PCB

I.e. vs. Would the reasons be similar to those answered here, but emphasized on unwanted capacitance, noise, and power issues?
10
votes
3answers
2k views

Voltage doubler

I'm a little lost as to what is going on in this circuit. The book I am reading mentions that the load would see double the voltage of the input voltage. How does this work?
3
votes
2answers
2k views

DAC settling time and output signal bandwidth

Voltage output DACs are usually specified by a settling time. If a DAC converter has a settling time of T, can it be used to faithfully reproduce a signal which has been sampled at a frequency of 1/T? ...
4
votes
2answers
2k views

Is there a cheap alternative to AVRs that can run the .Net Micro Framework?

Recently, I purchased a FEZ Panda and I've done some pretty cool stuff with it. Well, cool to me anyway. I recently had some ideas for things to do with LEDs and wanted to share them as kits. I see a ...
6
votes
1answer
5k views

How do I compute the lifetime of an electrolytic capacitor?

I am considering using a KZE series (by United Chemi-Con) electrolytic capacitor, which has a specified lifespan of 5,000 hours at 105°C with rated ripple current. Now, for an example assume I am ...
6
votes
2answers
103 views

Infrared Filtering from Laser Modules and Wattage Considerations

I have come across a project which used this Chinese laser module. Apparently from someone who worked with the mentioned laser, it emits IR light (noise) even though it's a green laser. While I was ...
0
votes
1answer
460 views

Using Arduino/Processing to print text on screen when an LED light up

I have a question regarding the programming of printing text on the screen after an LED lights up on a breadboard. Should we plug in the LED into the Arduino board or a regular breadboard? How do I ...
3
votes
3answers
11k views

RS485 noise problems: signal ground / common ground / isolation?

I'm experiencing a lot of noise in an RS485 network I've put together using ST485 chips. The cable lengths are very short (<1m total cable length), I'm properly biasing the A and B signals and I've ...
12
votes
10answers
28k views

Fastest way to get integer mod 10 and integer divide 10?

If a hardware doesn't support modulus or division operations, it takes many more CPU cycles to simulate modulus/division by software. Is there any faster way to calculate division and modulus if the ...
3
votes
1answer
18k views

A mobile power source for a laptop and a projector

My friend has asked me to do some marketing for his student targeted company. The hope is to create a good animation/flash video and project this (at night) inside the student campus onto the building....
5
votes
4answers
2k views

is it possible to install some device which will measure in real time the torque my diesel engine is providing at the moment?

It is easy to make a meter which will show the engine RPM, many cars have one installed. But to know the power in kW that the engine is providing right now, I also need to know the torque, because: \$...
14
votes
6answers
8k views

Why do real-time clock chips use BCD

I have seen dozens of different real-time clock chips on the market, as well as a number of processors with a built-in separately-powered real-time clock module. Nearly all of them not only store ...
0
votes
5answers
932 views

How to switch many (15) low power (40W) lightbulbs from a microcontroller?

The power rating on the bulb is the amount of power the PSU has to deliver in order for the bulb to light up the brightest right? Hence if it's a 40w bulb I need 40watts of power for it to light up ...
18
votes
5answers
29k views

Best pattern for WFI (wait-for-interrupt) on Cortex (ARM) microcontrolers

I'm looking into developing battery-powered software using the EFM Gekko controllers (http://energymicro.com/) and would like the controller to be asleep whenever there's nothing useful for it to be ...
27
votes
5answers
32k views

What is the purpose of solder mask expansion?

I see recommendations of 2-4 mils for solder mask expansion. But why is it necessary?
0
votes
1answer
285 views

xilinx jtag cable

could anyone please explain to me what are the CTRL and PROG pins in this schematic good for? with CTRL i know what does it do but i don't much get the purpose, so far i would say it's there just to ...
12
votes
1answer
3k views

Measuring ferrite core parameters

I have large amounts of inductors and transformers from power supplies or other undocumented sources. They are of course completely unmarked and I have no idea what kind of ferrite material they are ...
7
votes
3answers
2k views

is it OK to stack several DC-DC converters with their inputs connected in series to support a larger input voltage?

Imagine I have a single-IC switching DC-DC converter which supports input voltage up to 16V, for example a LM2727. Can I stack the inputs of such converter in series, for example 64 of them, and be ...
5
votes
2answers
1k views

Voltage used to charge a UPS-Inverter and its usage

I'm new to this area and know very little about electrons and how electrical components work. I'm always curious about Inverter/UPS usage. I'm from India and we have a inverter at home. It is ...
1
vote
1answer
550 views

Calculating effective bit precision of DAC due to range restriction

Say I have a 16-bit DAC which outputs a range from 0-5V. My application only requires an output from 4-5V. I am interested in the effective precision of the DAC due to this range restriction. Is the ...
1
vote
1answer
1k views

Schematic for 4-band stereo equalizer?

I wand to make a simple stereo 4-band EQ for a mid-fi amp I'm building. I draw my knowledge from this excellent article - however, it only seems to talk about peak/notch bands and not low and high ...
0
votes
1answer
345 views

RF Input Sensitivity

I read in a datasheet that the Input sensitivity of the AD4002 (RFin) is -10dBm to 0dBm. I know how to convert this to a voltage drop over a resistor, say 50ohm. But I got myself confused over the ...
7
votes
5answers
7k views

Solder very close together contacts

I have contacts that are so close together I'm either bridging them, or melting the neighboring one. What am I missing?
1
vote
1answer
2k views

Power input on l293d motor driver

Two of the pins on the l293d are labeled VS and VSS. Apparently they are both power. Here it shows VS being supplied with 12V, while vss is receiving 5V. Here, it shows both receiving 6V from the same ...
2
votes
1answer
2k views

Can I replace LM358N with NE5532N dual op amp?

In this circuit LM358N 1MHz 32V dual op amp is used (+12V and -12V). The question is, can I simply replace it with NE5532N 10MHz +-22V dual op amp for up to 8MHz DDS signal source? Basically, this ...
2
votes
4answers
2k views

Standard way to reverse a motor?

Is using a relay and some switches a standard way to reverse a motor or is the preferred method to use a H-Bridge? The circuit for reversing a motor with a relay looks like this: Note that this ...

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