All Questions

6
votes
2answers
2k views

Why is RS422a more immune to electrical noise than RS232?

I have read that RS-422a cable uses a 20 mA current loop instead of voltage levels. This makes the systems more immune to electrical noise, so the cable can be up to 3000 feet long. I do not ...
7
votes
2answers
298 views

Export restrictions on programming equipment

I have a friend that works for an overseas manufacturer. He sells programming equipment to companies that have products with multiple Programmable Controllers embedded. I raised the subject of "export ...
5
votes
1answer
6k views

Cleaning up a 5V Switching DC-DC converter for low noise 5V output

I have a project that I have to hook to a 5V bus coming from this DC-DC switching converter. I need to clean this up to use with a logamp (LOG114), photodiode, and ADC (ADS8519). I would also like ...
13
votes
2answers
3k views

Compiling code to run from external RAM

I am considering designs for a minimalist game system based on a PIC18F85J5. Part of my design is that games can be loaded from an SD card without reprogramming the chip or flashing the program memory....
7
votes
2answers
2k views

Seemingly unstable basic PIC18F2550 circuit

From my work I've had quite a bit of experience with hardware development, but purely from a supervisory role, and so recently I've been playing around with ground up MCU circuit design to try to get ...
4
votes
1answer
438 views

Will DDR2 memory work with DM pins tied to LOW, if no data masking is required?

I have a board with the LDM and UDM pins swapped. If they are tied to low, will the memory still 'work', given that data is always written to mod 4 addresses and always using all 4 bytes? Memory is ...
-3
votes
1answer
780 views

What Fuse Is The Correct Replacement?

I got a HP Universal Counter on my desk, but it did not turn on, so I checked the fuse. The original fuse reads SOCSD4 D250V150mA What kind of fuse could I use ...
5
votes
2answers
2k views

How do I modify a DC electric generator to get the same power at a lower speed?

This will be a theoretical question. Suppose that I have a DC generator, and I'm getting 300VA power from it when it rotates at 2000rpm. I want to make it run at a lower speed of about 700rpm, and I ...
4
votes
3answers
7k views

Using avr-gcc _delay_ms causes chip to freeze

I have a ATmega328-PU chip which is setup to use the internal oscillator without dividing clock speed by 8. The first thing I did was to use a really simple program I uploaded; a program which turned ...
3
votes
2answers
576 views

Electro-Mechanical Connection: from screw straight up to electrical-wire?

I am developing a system that includes aircraft cables with threaded studs - screw endings that are used for mounting. Here is a picture of the stud connected to a cable: Now I am searching for an ...
4
votes
1answer
2k views

Using Android Accesory mode to access a USB serial device, use a VNC2?

In a current project we use an Android application that talks to a USB Serial device (which speaks the Prolific USB serial protocol). This works fine with Android devices that support USB Host Mode, ...
0
votes
0answers
111 views

How can I test microprocessor / microcontroller? [duplicate]

Possible Duplicate: Is it feasible to test microprocessor/microcontroller? As far as I know the manufacturers do it before shipment. How they test microprocessor / microcontroller? However, if ...
58
votes
9answers
31k views

Why on earth are o-scopes earth referenced?

Thinking about it: You would never find a "Grounded" multimeter as robust and useful if a path to ground through the multimeter were introduced, modifying the circuit's behaviour and possibly damaging ...
1
vote
1answer
192 views

Help finding a freescale MC68LK331CPV27 datasheet

I'm looking for an old cpu datasheet which seems to have disappeared from existence. It is for a freescale MC68LK331CPV27. I've ran out of stock on an old cpu and the replacement (MC68LK332ACAG16) ...
2
votes
1answer
545 views

Identifying and dealing with counterfeit parts

There seems to be a growing awareness of counterfeiting in the parts supply chain and the government seems to be pushing responsibility back onto suppliers and manufacturers (Clamping down on ...
6
votes
2answers
628 views

XOR Gate malfunctioning

I have an XOR gate wired (74LS136) and I don't think it is working properly. Here is the table I think it should be outputting: ...
-8
votes
4answers
482 views

Is there any microprocessor with only input pins or only output pins?

I want to know if there is any microprocessor without input? or without output? I mean single way one.
3
votes
2answers
1k views

early accumulator based machines

Wikipedia says that many of the early machines were accumulator-based machines. My guess is that in those machines the accumulator did not play the role of a speed-up register as do registers in today ...
3
votes
2answers
3k views

Which parts of this rotor can be made out of plastic?

I'm asked to redesign a rotor, by making as much parts of it as possible out of plastic. The issue is its weight, we want to make it as light as possible. Especially the shaft & axis of it is the ...
4
votes
1answer
3k views

How to measure Li-Po battery leakage?

I'm working on a low-low power system, which is powered by a little solar panel and a Li-Po (Lithium-ion Polymer) battery, which can be \$20\$ or \$ 50\:\mathrm{ mAh}\$. The capacity by now is not ...
2
votes
1answer
689 views

PCI-Express on SATA or SATA on PCI-Express damaging?

OK, at first this sounds like an obvious and serious design error. But I'm trying to figure out muxing the SERDES signals on a PCI-Express Mini card, such as WiFi cards in laptops and mSATA cards in ...
4
votes
1answer
301 views

How can I measure which finger is moving in a glove?

I am considering building a pair of gloves that make a chorded keyboard. In order to measure whether or not a finger should be triggered, I intend to leverage the fact that as you curl your fingers ...
5
votes
1answer
2k views

Analog Video PCB Layout

What special considerations and/or constraints are typically applied when routing analog video signals on a PCB (e.g. VGA, NTSC, etc). I'm thinking try and keep them routed on a single layer (i.e. at ...
3
votes
1answer
722 views

Antenna modeling software and tutorials

I'm starting to learn about antenna theory, feedlines, and different types of matching. I can build antennas etc from plans but I would like to be able to design my own and understand their ...
5
votes
7answers
9k views

Looking to create 36 channels of PWM control for LED sculpture

I'm a sculptor, not an EE, but I'm trying to incorporate controllable LEDs into a piece that I'm working on, and I could use some advice figuring out a practical approach. I'd like to be able to ...
1
vote
2answers
937 views

Quartus - Export Verilog as Gate Level (FPGA)

I've got a project in Altera's Quartus II software which is written in Verilog. I'm curious if anyone here has figured out how to export the Verilog as a gate level netlist. I'd like to simulate the ...
3
votes
1answer
530 views

Arduino LilyPad Input Voltages Below the Input Voltage in Specs

The LilyPad spec page says: Input Voltage 2.7-5.5 V I understand that an input voltage greater than 5.5 V would damage the device, but what if it's below 2.7 V?...
3
votes
2answers
7k views

STM32, Keil and *** error 65: access violation at 0x60000000 : no 'write' permission

I tried to run LCD software in Keil for STM32, but I got *** error 65: access violation at 0x60000000 : no 'write' permission Do you know how to solve that error ...
6
votes
1answer
198 views

Fine-grained sensing of distance between two permanent magnets

(disclaimer: bit of an electronics newbie here) I have a bunch of little magnet ball-bearings that I was playing around with the other day. I formed them into a strand, then fixed both ends leaving ...
4
votes
1answer
5k views

What are the male pin ends on stranded jumper wires called?

I have a pile of stranded breadboard wires, but need to buy or make more. The red one on the left have a solid metal pin, a molded plastic barrel, and stranded wire, and was purchased at Amazon. Most ...
1
vote
1answer
570 views

PCI-Express timestamp source that can be used in Windows?

I need to do some accurate time measurements and I need to have access to a affordable / cheap and somewhat more reliable timestamp/time source than what is built in Windows/CPU. I need to read the ...
4
votes
2answers
3k views

Programing another atmega8 running on 1MHZ internal RC oscillator using Arduino IDE

I want to write code for another atmega8 running at 1MHz internal RC oscillator using the Arduino IDE and its libraries. I have an ISP programmer to burn the code. What are the things that I should ...
3
votes
3answers
832 views

How to calculate power from this diagram?

I need to calculate the apparent power, active power and reactive power and I only got this diagram ( in german ): So the equation for active power is $$P = \int_0^T u(t)i(t) \, \mathrm{d} x$$ ...
0
votes
2answers
3k views

Program a PIC16F877A using VB.NET

I have bought a PIC16F877A microcontroller and its board before and since then, I haven't used it much because I don't really have enough time and patience to learn C. I was thinking to buy a ...
2
votes
2answers
646 views

What would I need to open a circuit (a usb cable) for a few seconds, on a given time?

I have a USB cable connected to a USB modem. On a specific time of day (say, at midnight - but it should be configurable) I would like to open the circuit for a few seconds. The result should be ...
4
votes
3answers
2k views

How to read/generate phase-shift-keying (PSK)

I'm trying to reverse engineer a piece of electronics that seems to be using ~1Mhz differential phase shift keying to send a signal over a 2-wire line that's also used for low-voltage power. So ...
2
votes
3answers
20k views

What is the difference between a solar system battery and a normal battery?

I want to design a solar powered system but I am puzzled by the type of battery which I should use. I am aware that for solar applications special batteries are available but I could not find any in ...
4
votes
3answers
4k views

If a flip flop has a setup violation and goes metastable, is it guaranteed to settle to the input value when it finishes oscillating?

If I'm using modern D-Flip flops and miss the setup time (i.e. my D input changes close to the clock), the danger is that the F/F will go "metastable" and spend some time oscillating. Standard ...
1
vote
3answers
9k views

How does this OP-AMP non-inverting amplifier work?

In this non-inverting circuit at page 6 of "A Single-Supply Op-Amp Circuit Collection (SLOA058)": I've found out the equation to be (assuming Vcc=+5 V): $$ Vo=(Vin-2.5)*\frac{R_{1}+R_{2}}{R_{1}}+2.5 ...
0
votes
1answer
8k views

Boost circuit using UC3843-IC

I would like others to explain how to make an buck or boost circuit using UC3843-IC. I am constructing a solar power supply, that can be setup as an alternate power source so that it can be fed to ...
0
votes
1answer
828 views

how many data in Arduino progmem?

How much data can I save using PROGMEM, on the Arduino platform (Atmega328)? For example: ...
-3
votes
3answers
2k views

Implementation of traffic lights

I'd love your help with implementation of traffic lights of 15 second cycle. The red light is on for 6 seconds, then the yellow (At the same time with the red for two seconds), then the green light ...
8
votes
1answer
22k views

WiFi module says “mini PCI-e format” with “USB host interface” - what does this mean?

The specifications of a WiFi module meant for embedded projects, says -- mini PCIe format Host interface supports USB.2.0 Works with any board with mini PCIe. Not sure about the interplay of mini ...
1
vote
1answer
543 views

How do I make the Ardumoto shield work properly?

I'm having issues with the Ardumoto shield. I want to use a motor at 5V with a 12V 2A power supply connected to the Arduino board. From my understanding, the ardumoto shield gets its power directly ...
6
votes
3answers
10k views

How static electricity gets build up and how it gets discharged?

I get electrocuted all the time by contacting metal object, by running a cart in the grocery store, opening the car door, touching the door knob. I have reseached various article of how static ...
1
vote
1answer
1k views

Can I use diodes as part of a circuit to multiplex several analog signals?

The micro controller I am using (AVR) only has 1 ADC port, but I have 6 analog peripherals, essentially potentiometers. Since I want to use these 6 different signals on 1 pin, I thought about a design ...
21
votes
5answers
24k views

When/why would you use a Zener diode as a flywheel diode (on the coil of a relay)?

I have just been cogitating on the tutorial at http://www.electronics-tutorials.ws/io/io_5.html, and in the discussion of flywheel diodes it includes this sentence without further elaboration: As ...
0
votes
1answer
682 views

Design plan for a calculator

I bought an MSP430 to learn more about microcontrollers. My ultimate goal is to build a graphing calculator. I have read a few other posts about this but I still have some questions about the ...
0
votes
1answer
672 views

how to design switching regulator in battery operated device?

My device consists of ATMega, GPRS modem and sensors. Modem occasionally hangs and I need to reset it from mcu. The whole system is powered from li-ion battery. I can't find any switching DC-DC ...
9
votes
3answers
584 views

Laser - damaging to your eyes?

Will a <5mW laser Class IIIa become less dangerous to the eye if I supply it with less current/voltage? Or is there something about the laser itself that makes it dangerous?

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