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H: What NPN transistor should I use?
I need to control a 12 V 5 A (or 3 A if need be) with an Arduino UNO which has 5 V and 40 mA. Unfortunately I don't know how to read transistor data sheets. What NPN transistor should I get for this project?
AI: You shouldn't use an NPN transistor for this project. There are parts ... |
H: how to calculate total resistance in circuit with parallel and series resistors connected
A battery of EMF 8.0 V and internal resistance r = 1.0 – is connected to an external circuit as shown:
I need to find out the total resistence and my problem is that I dont know which resistors consider parallel and which are... |
H: Conversion of voltage of battery
I have 9 volts battery. What resistance do I need to have 5 volts. And how to calculate?
AI: You need to know the current you will draw, and then use Ohm's law to calculate the resistance. For example, if you draw 4 mA then the resistance will be 1000 Ohm.
However, as the current us... |
H: How to drive high power LED and Arduino by the same power source?
I am building a plant light consisted of 24 high power LEDs (Cree ML-E) and an Arduino Uno. I would like to power the LEDs and the Arduino by the same power source. Since creating circuits for dealing with household power requires quite a lot of expe... |
H: Is that possible to run AC motor through website?
I wanna know how is that possible to start ac motor through php based website. What tech or device do i need to look for?
AI: I'll hold my answer as general as you asked your question:
get a Raspberry Pi or something similar
set up Apache2+PHP
get a very strong rel... |
H: What component/device to use for a front-eye display
I need to display information in front of my eyes, just like Google Glass, but in this case, it has to fill a bigger field of view (is it the good term?). I have already thought about a couple ways to do it, but I am not sure they be relevant :
1) Using reflectio... |
H: How can I communicate between micro-controller and PC without the use of RS232/USB Adapter?
I use an NXP micro-controller, P89V51RD2, and use a RS232 to USB converter to program it. I'd like to communicate with the computer to send data but without using the RS232 adapter and convert serial data from micro-controll... |
H: What is INCH/(MILLIMETER)?
This datasheet (see page 22) has the dimensions of its diagrams in "INCH/(MILLIMETER)".
What does INCH/(MILLIMETER) mean? Is it a unit of length? (I would expect it to be unitless, given length/length is unitless.) If it is a unit of length, what is 1 INCH/(MILLIMETER) in millimeters?
AI:... |
H: Voltage Level Translation: LCD(5V) -> GTL2000 <-> MCU (3.3V)
I am trying to interface a micro-controller (LPC11C14) to a LCD. The LCD has Vih = 3.5V so I cannot directly connect the uC pin to the LCD. For this, I found a GTL2000 chip which looks like it might do the job. But here is the issue that i am not sure abo... |
H: Why are the pads different for THT / SMT components in Eagle?
I am learning Cadsoft Eagle and have noticed that the pads for SMT devices are on the 'top'/'bottom' display layer, whereas the pads for THT components are on the 'pads' layer. Why is this?
I have enlarged the pads for the SMT device so that I don't comm... |
H: Beginning programming for Atmel uProcessors
I'm taking the next step, going from my Netduino into the smaller microcontrollers from ATMEL (since there is no really tiny (tinier than the netduino) stuff running .NET).
Also have some experience with ATML and some (silly) assembly coding back from when I went to colle... |
H: Creating a high-current bus on a PCB
I'm planning a custom power-distribution / fuse-board for in-car application, but that requires carrying high currents (50A+ @12v*) on a PCB trace. Since I'd like to keep the board cost, and physical size down, can anyone suggest efficient (as in easy & inexpensive) methods for ... |
H: Transformerless inverter from 20*12V batteries
Is it possible to convert 240VDC from 20*12V batteries to 180VAC-240VAC pure Sine Wave?
i have an idea using H-Bridge mosfet drivers....But i have seen on web that 350Vdc is must to convert it to 240VDC...
AI: It is possible but awkward. 180 VAC RMS will have peaks of... |
H: Device Descriptors in Serial Communication
I was wondering if there was any Descriptor part in the data packets during RS 232 based Serial Communication. If not (apparently) then how does the computer decide regarding the type of device connected.?
AI: There are no packets in traditional RS232 communication, let al... |
H: Two MinIMU-9 v2 with LPCxpresso, or Arduino Uno/Mega
I am working on a project that interfaces two IMU sensors to one microprocessor (NXP LPCxpresso). The purpose is to read both of gyro and accelero at two different place on the bodies. I have foolishly rushed to buy this product:
http://www.pololu.com/catalog/p... |
H: Op-amp circuit works correctly only when the oscilloscope's probe is connected to it
I'm using a piezoelectric speaker as an shock sensor. I made a simple non-inverting amplifier using the MCP6021 op-amp as shown in the circuit below. I'm only interesting in the positive output of the speaker so I put a diode to pr... |
H: PCB Edge to Edge Connectors
I'm trying to find a way to connect PCB boards edge-to-edge so that I can make a "train" of PCB boards in a row.
It seems to me that this should be straight forward to do using a a female to female edge connector, but when I've looked for such a beast I've only found one solution that's... |
H: Discharging RLC. Kirchhoff's second law
I have been trying to solve this homework problem for who-knows how many hours. I could break it down enough as to specify the problem I'm facing into a single question:
For the following circuit with a charged capacitor, is \$ v_C + v_R + v_L = 0 \$ the right term? Or should... |
H: Eagle: Removing unwanted bits of copper pour
I have lazily made a copper pour in Eagle by highlighting a rectangle around my irregular shaped board. How do I then selectively remove the copper pour from outside the board boundary and the little unconnected pointless bits between some components?
AI: Uncheck the orp... |
H: Atmega 8 is not programming once it is set to external crystal?
I am using Asim Khan's Parallel port Programmer to program my AVR ATmega8 controller. The Problem is when I changes fuse bits to external high speed crystal, then the next time programmer does not detects the programmer. I am really frustrated to figur... |
H: Sync 12 Arduinos - I2C vs Serial
I've been given 12 arduinos (Mega) and 12 breakout boards (custom built. they pump up the output of the digital pins to 12v @120mA) to control around 300 LEDs. I'm using a pseudo PWM library to fade the LEDs.
This could have been achieved with a much, much cheaper setup. Open to sug... |
H: What are FIT's and how they used in reliability calculations?
In Military, Medical, Space, Professional eqt. design there is a need to be able to prove that your device can last a certain length of time with a certain confidence level. Or that reliability must be used in design to inform the design direction, eith... |
H: Why is silicon used to make microchips?
On my quest to better understand how computers work at a deep level I have come to the question of why, exactly, silicon is used in microchips. I always assumed, naively, that silicon had a very high electrical resistance and so it made a good material to sandwich other mater... |
H: LiPo discharge circuit doesn't work
A friend of mine gave me this circuit to discharge a 3V7, 5000mAh single-cell LiPoly accu:
simulate this circuit – Schematic created using CircuitLab
The zener is to make sure that the circuit stops when the voltage gets below 2V7, so that the accu doesn't get below the critical... |
H: Inexpensive multimeter for integrated current measurement
I'm building a simple circuit with an Arduino Nano board, which will read signals from a Hall sensor and periodically send pulses to a small 5V solenoid. I'll drive it from 6xAA batteries in series, producing 7.2V. The on-time of the solenoid will be very sh... |
H: Any disadvantages to single-supply mode?
I am using the ATMEL ARM SAM4S MCU for a project. It supports a single-supply mode where an internal voltage regulator provides the 1.08-1.32V necessary for VDDCORE and we need only provide 1.62-3.6V to VDDIO.
I'm just interested to know if there is any situation where one ... |
H: SU-48 footprint
This datasheet specifies the packages for the components, but not the associated footprints.
The package of interest for me is SU-48. The obvious search brings me to this outline, but still no footprint.
Where can I find footprint information for the SU-48 package?
AI: Despite what Olin says, it's a... |
H: magnetic field outside solenoid
It is written in our course book that the magnetic field outside a solenoid is negligible and almost zero. Why is it negligible? Is it negligible compared to the field inside solenoid or is it nearly equal to zero?
AI: A simple model to help you visualize: The magnetic flux forms lo... |
H: How can I switch a high current with a low-rated switch?
I'm designing and building a breadboard power supply for myself, which draws power from an ATX-like SMPS (Mains in, single Molex plug out) via a 4-pin Molex connector. The design includes a switch to select either 12V or 5V output, but the only appropriate sw... |
H: symbols for ep3c5e144 and ep3c25e144 in Eagle
I am using ep3c5e144 to design a PCB board. Sadly, in Eagle I cant find the exact library and symbol for this device, but only its near relative ep3c25e144.
I have some questions:
How different is the pinning for ep3c5e144 and ep3c25e144? Can I reuse the symbols of ep3... |
H: What makes intel capable of very high clock rates?
What are the determining factors responsible for why Intel chips can clock at 4Ghz or higher speeds, while other processors such as ARM can't? Is it because Intel's state of the art fabs or is it the architecture of the x86? It hard to understand how a complex chip... |
H: create Eagle library for bsdl file
I am designing a PCB Board for Altera Cyclone III EP3C5E144. However, I cant find any library for this device in Eagle.
Is there anyways I could create the library and symbol for this device, based on this bsdl file?
http://bsdl.info/view.htm?sid=599926c619a107a388ca59b002289d77
... |
H: Considerations For Motor Cables: what are the downsides to ribbon cable?
My friend (a Mechanical Engineering student) is building machine that uses an array of motors in an application where they are under almost no load. He showed me the thin, old, ribbon cable he intends to use to power them, and it seemed like a... |
H: powering a fan with ATX PSU 5v standby when off, with 12v when on
Using an ATX PSU, how would I design a circuit to power a load (dc fan) with 5v standby when PSU is off, and with 12v when PSU is on. I want to control (on/off or pwm, it should not matter?) the fan from a 3.3v mcu (powered with standby 5v) using a s... |
H: how to wire up LIS302DLH with arduino? (or similar, small accelerometer)
heads up: I'm new to electronics and have just started working with the arduino.
I'm trying to hook up a LIS302DLH accelerometer (spec sheet) with the arduino. I've successfully managed to get the adxl335 (e.g. link) to work but the adxl335 i... |
H: Open loop op-amp white noise difference amplifier
I want to amplify the noise generated by a MAX8069 voltage reference, using direct coupling in order to preserve the low frequency components. The frequency band of interest is from 1Hz to 44Khz. I'd like to be able to measure the power spectrum at different frequen... |
H: What's the input resistance of an opto-isolator?
I need to sense if a 48 volt power supply is supplying voltage or not, I plan on doing this with a opto-isolator and I am happy with the output circuit from isolator.
Can I connect the input of the isolator between 48 and 0 volts, or do I need to add in a extra resis... |
H: What does a beginner need to know to build a programmable heater based on resistance heating?
To build a programmable deep fryer, as a learning project for more serious checmical reactors, I need to build a programmable heat source that can be controlled in response to sensor readings and a schedule. I'm a programm... |
H: Can I add resistors?
How can I achieve 10k resistance?
I just got my photocell in the mail, totally forgot the 10k resistor. The thing is I have a lot of different resistors in the span 1, 10, 27, 37,56, 68, 82, 100.
Is there a way I can put them in parallel/series and make a 10k? Or do I need a 10k? How does it wo... |
H: How does an AND gate behave in this situation?
I'm a beginner and I want to know how a logic gate circuit works:
Will the led turn on just when I press the 2 switches? Or I'm doing something wrong?
AI: The AND gate has a truth table that looks like this:
Input A | Input B | Output
0 | 0 | 0... |
H: Solder Mask Color Code
Is there standard that recommend guidance of particular colors of solder mask?
A while back I was told by a local assembler that BLUE typically indicates the circuit is ROHS compliant. Yet my Google foo does not find any supporting evidence. Were my Google foo is swamped. So there may be some... |
H: Minimizing Karnaugh map
I have the following Karnaugh map's for JK flip flops. I've attempted to minimize them myself, however whenever I go to implement them I run in to an error. Anyone able to see if I've made an error in my minimization.
(originally uploaded to jsfiddle)
Hope you can help, hope this is the co... |
H: How to find currents of all nodes using superposition theorem
Given this circuit:
simulate this circuit – Schematic created using CircuitLab
Using the superposition theorem, I need to find the current of all the 3 nodes of the circuit.
Using superposition I've found that the current from the source:
V1 is 6.32A =... |
H: SSC-32, can I and how can i program it
A friend recently gave me this board that he had never used and didn't know anything about it. It had a USB to serial cable plugged into it with the driver software that I installed and it had a servo motor included. Question 1- is this a micro controller (i know it has someth... |
H: How do I make a micro-controller act as a finger on a touch screen?
I want to make a device that I can place on a capacitive touch screen and it will start tapping the screen repeatedly. Is there any way to do this with the Arduino?
AI: This can be done if you get an Arduino plus a servo controller that has a rig t... |
H: An opto-coupler/triac oddity -- is it a problem, and is there a solution?
I'm using VO2223A opto-coupler/phototriacs to drive some low-current mains lighting with a PIC controller. All are working fine, but when the (DPST) mains switch is first turned on during system power-up), on 50% of occasions the lamps will b... |
H: What is this IC marked IA89G or 1A89G?
Please I need a bit of your help. Do you know what IC is this marked IA89G or 1A89G perhaps? I've tried Googling but to no avail. I'm really wondering why this is such a hard nut to crack.
Here are a few snapshots of the IC:
Thanks a lot!
Joemill
AI: Much as it might look li... |
H: Build an Audio Toggle Box
I want to build a small box with two audio inputs and two audio outputs, with two switches to control the current input/output. Something like this: http://www.youtube.com/watch?v=mQzLnt0_-zU
I've wired up the following diagram in CircuitLab for how I think this should work:
https://www.c... |
H: Receiving videos via wifi
I'm working on a electrical board that should receive videos from a server via WIFI. The size of the video is around 100 MB..it will be stored afterwards into an SD card ...so my question is what WIFI module should i use for this type of data?
AI: The file size won't matter per se, it's th... |
H: Dimensions of SO8W package footprint
I'm looking for the pad dimensions and land patterns for the SO8W package. This page has drawings of many SO footprints, but no dimensions.
Where can I find dimensions for the SO8W package's PCB footprint?
AI: The SO8W (Wide) package dimensions are as follows:
For confirmation,... |
H: Replacing an illuminated rocker switch with 2 terminals
I am trying to replace a burnt out illuminated rocker switch in an electric fireplace heater. I ordered a replacement switch that looked like it would do the trick, but failed to notice that it had three terminals, while the original switch has only two.
The... |
H: Writing a driver for a wireless usb dongle for an AVR microcontroller
I have an avr micro-controller which supports USB OTG. I also have a wifi usb dongle which connects to the internet. I need to write the required drivers in order to interface this usb dongle with a wifi module. What books would be the right star... |
H: Wiring a SPDT Relay
I am new to Electronics and I am currently trying to wire up a SPDT Relay. I must admit I am totally confused. I want to have a SPDT switch that simply switches the relay over. Any pointers would be appreciated. When I currently energize the relay, I hear it cycling, which I would image that is ... |
H: What kind of inductive load does a mains LED lamp present?
This follows on from another question I'd been asking. Having been 'gifted' dozens of mains LED lamps, I've been blithely assuming that they don't offer much in the way of inductive load.
But, of course, they aren't just a mass of LEDs: there's a rectifier... |
H: Pad size for JEDEC 1.0mm pitch 27x27 device
I have a JEDEC 1.0mm pitch 27x27 device. The only missing information I need to build a footprint for it is the size of the pads.
What size of pads should I use for a JEDEC 1.0mm pitch 27x27 device?
AI: Xilinx application note XAPP426 "Implementing Xilinx Flip-Chip BGA Pa... |
H: PWM Motor speed control using PIC; What mosfet to use
I have a 5V PIC16f877a controlling the speed of the motor 12V which has a power rating of 8W; the current will be around(600mA) am I correct?
The motor is basically a small water pump commonly used in aquariums.
After much research; I still don't know what is th... |
H: How much Ampere is displayed on the multimeter?
here is a picture of a multimeter:
the display shows: 02,0
is it 2A or 2mA ?
AI: The range switch on the front of the multimeter shows the maximum current that can be measured on that range. The range switch is pointing at the "200m" DC Amps range in the picture. T... |
H: Microprocessors/Microcontrollers - Do registers have addresses?
My Embedded Systems professor keeps referring to the memory locations of registers as their respective "addresses". I'm confused by this; I was always under the impression that in any microprocessor, the CPU registers don't have addresses since they do... |
H: How do we OR two bits in ATxmega128?
I am working with ATxMega128 and programming it in C.
I have two inputs coming from a sensor and I want to turn on an LED when I get output from either of the sensor.
I can blink my LED if i get output from both of my sensor (i.e. I can do ANDING using &) but I do not know how t... |
H: Why are typically fatal currents non-lethal when they pass through your body for a short time?
I've been reading up on electrical safety, and the commonly cited controversial quote "it's not the volts that kills you, it's the amps". What I have gotten out of these sources is that it is in fact the amperes that stop... |
H: Would it harm a LiPo to charge it in several periods?
I have a 3.7V 5000mAh Lithium-Polymer battery cell, which I'm charging with the MCP73831, using the typical application circuit on page 1:
I have \$R_{prog}=2\text{K}\$ and \$V_{in}=6.0\text{V}\$. Normally, I'd charge the cell during the evening and night, sinc... |
H: Question related self powered USB Hub
We have a requirement, which is a normal self powered USB Hub, with individual power control of the ports, i.e in addition to a normal Hub, we want to remove the power to any of the downstream port on the fly using on-board micro controller.
I am not an expert of USB2.0 specifi... |
H: Controlling MSP430 PWM with a Laptop
I have written a code which takes two digit number from laptop and changes the PWM dutycycle to that number. It is part of a bigger requirement where I need to control motor speed over UART.
#include "io430g2553.h"
#include <stdint.h>
void PWM(uint8_t duty_cycle);
void PWM_Co... |
H: Powering an IC from a GPIO line
I've got a low power application which will be powered from a Li coin cell. I've achieved satisfactory sleeping current with my chosen MCU.
The application ADC IC however is a different matter: 900µA while inactive -- way too much for a coin cell application.
So I thought why not i... |
H: How does Fourier series apply to signals?
I have the complex form of Fourier serie:
It says that an and bn are real numbers, while c is a complex number. I need Fourier serie to represent an electrical signal that should transmit bits. In this case, what do an and bn represent? How do I calculate them?
AI: Fouri... |
H: Saturating a N-Channel MOSFET
I have created a schematic for a circuit that I wish to create. I believe the underlying circuit is pretty solid; however, I am having trouble picking parts with the right specs. I have attached the schematic of the circuit I wish to create. My question has to do with the transistor. H... |
H: F-SW22 vs F-SW33 flux. What to these figures mean?
I was thinking of purchasing a no-clean flux pen from my supplier, but there are two options, F-SW22 and F-SW33. What do these codes mean and what types of job is each suitable for?
AI: F-SW-22 is weakly corrosive and contains inorganic salts.
F-SW-33 is non-corros... |
H: Will a device capable of receiving a 200 Vrms input signal happily accept a 200 VDC signal?
To the best of my knowledge, Vrms is used to express an AC signal as the equivalent DC signal that would produce the same power dissipated in a resistor R; I believe this is best calculated using a thermistor to measure the ... |
H: How do I know if my hall-effect sensor is working correctly?
On pg. 18 Figure 5 of this data sheet you will see a pulse train required to program the sensitivity of the A1362 Hall-Effect sensor.
I am using the following circuit:
Using Figure 5 from the data sheet, I simply power on the Hall-Effect sensor by sup... |
H: How electronic components keep synchronized?
So, voltage travels super fast right? Still, there has to be some lag between voltage traveling from one transistor into another. How is a circuit kept synchronized then?
AI: The need to ensure that signals arrive at the proper time is the core of what it means to design... |
H: Wear leveling on a microcontroller's EEPROM
For example: The datasheet for ATtiny2313 (as do most Atmel AVR datasheets) states:
128 Bytes In-System Programmable EEPROM Endurance: 100,000 Write/Erase
Cycles
Imagine a program only requires two bytes to store some configuration, the other 126 bytes are effectively... |
H: Why is the base currect incorrect?
My multimeter shows:
Ib=218uA why?
But my calculation shows, it should be: 8.5uA
I used the formula:
Ib=(3.1-0.7)/(10k+271k) [I take Beta=270, BC548 transistor.]
What is the problem? Why is Ib = 218uA, instead of 8.5uA?
AI: The base resistor multiplication effect that you used in... |
H: Do any SMT components require hand soldering due to heat limitations?
It has been claimed on another board that some SMT components cannot be used in an automated production line (i.e. reflow or wave soldering) because they cannot withstand the heat/temperature. Hand soldering is used to avoid these problems.
An ex... |
H: Why does active low even exist?
In my career I've often encountered signals that are active low (Reset being the most common). I've even seen interfaces where all control signals are actively low.
To me, this is very unintuitive and confusing.
Why is there ever a need to use actively low?
Is it merely historic or ... |
H: Can I use Formula SP-30 self-cleaning acid paste flux?
I am a complete noob when it comes to soldering. I've only done a little bit in the past and it was years ago. Today, I bit the bullet after reading about how to solder and purchased some soldering supplies a the local Frys. When I got home I read the label for... |
H: Zero crossing detector: do I really need the 7W resistor?
I am trying to provide zero crossing detection to my controller. Using the schematic below, I managed to generate square wave signal, representing positive v/s negative half-period. The problem is that the resistor needs to be quite large :
CTR > 10%
Max dio... |
H: What is "Saturated CTR" of an optocoupler?
For example, in the datasheet of 4n27: .
So what is saturated and what is non-saturated CTR?
AI: Page 134 of your datasheet: "DC Current Transfer Ratio" and "N" for "Normalized".
This is the ratio between collector current and LED current. If you vary the current through ... |
H: Motors controlling Arduino usb question
simulate this circuit – Schematic created using CircuitLab
I made a RC car with an Arduino board, using an H-bridge to operate the motors. I connect them through a capacitor and a diode to the +5 V pin of the Arduino board to avoid damages on the board. I wrote a simple pro... |
H: How to analyse Darlington pair?
Is the LEFT circuit of darlington pair, equivallent to the RIGHT transistor circuit?
Is my asumption true?
I replaced the two transistors in darlington pair with one; having beta equal to the product of betas of the two transistors, and the voltage from of 1.4 (0.7+0.7) across Base ... |
H: Do I need any specific hardware and/or software to use Mechatrolink for communication?
I googled it and know that it is a communication protocol.
My question is that whether I need any specific hardware and/or software to use Mechatrolink for communication?
Also if possible, please tell me the advantage to use Mech... |
H: How paint an electronic circuit?
I want to make a electronic circuit more hidden. So, I want to make it all black. The easy way is get a spray ink and use it. But will it work? Which ink or paint I can use?
AI: If you want to make a small circuit less obvious, one way is through potting. The potting material is ine... |
H: Simplifying a circuit to measure current
So I'm to calculate the current in the places I put the ammeters in (yeah, I reckon one of them is turned around :)):
And while I can calculate such things for series or parallel circuits, I was taught I should first try to simplify the circuit and do it with Ohm's law and ... |
H: Any reason not to use Timer0 on AVR?
Just a basic question... For arduino/avr/ATMega328 I find lots of examples using Timer1 (there's even a whole library for it) but rarely any that utilize Timer0 (or Timer2).
Now, I know that using any of these timers to control an ISR method will disable the use of PWM on it's a... |
H: Wireless communication with robot
I am making a simple robot, and am using a relatively cheap RF transmitter and receiver to send commands to my robot. Essentially, the transmitter end would send data from an AVR MCU via its UART to the RF transmitter, and a similar setup on the robot would pick up the data.
So wha... |
H: LTI Response Help
A system is known to be LTI. The response of the system to a step function u[n] is δ[n] + δ[n-1].
a.) Find the response of the system to 2u[n] + u[n-1]
b.) Find the response to the unit impulse δ[n].
My professor hasn't been doing a good job of explaining this concept so far, please help!
AI: a.) ... |
H: advice on a transformer for power-supply
i know this type of question is common and yes i could just buy a known transformer for $10 on ebay or something. either way :)
i am interested in building my own power supply, something variable around 3-30v dc and maybe with a digital voltmeter built in. i was thinking of ... |
H: Apply PWM signal to PIN of a Microcontroller
I am using the MC9S08DZ60. I have been give a circuit diagram according to which i must program the micro-controller. I am using Code warrior with Processor Expert which allows me to initialize the required registers, i don't have to write the code for the same.
Requirem... |
H: Is wire wrapping still used nowadays?
I know that wire wrapping was used in critical applications where reliability was a major concern because it is more reliable than PCB based assemblies. But is it still true?
The AGC (Apollo Guidance Computer) was wire wrapped but what about current designs?
Are mars rovers, sp... |
H: How do you run a 5v MCU circuit on a 12v car battery?
My Archery club has asked me to design and build a Traffic Light system for shooting, but they want it to run on a 12v car battery as this is what our previous system ran on.
I'm going to make the system using the pic18f4550 as the controller, so it can have an ... |
H: Decreasing voltage without decreasing the current
I have got two 12 V 7.2 Ah lead-Acid batteries, which are connected in Series (26 V after charging). The batteries are connected to a step-up / boost module which have to be 2 V higher than the input. So the min. output is about 28 V
I want to use this to power an "... |
H: How to test if a Near Infrared Emitter and Photodiode still working?
I suspect that my NIR emitter and Photodiode are not working.
Emitter http://www.thorlabs.com/thorproduct.cfm?partnumber=LED1450E
Photodiode http://www.thorlabs.com/thorproduct.cfm?partnumber=FGA20
For emitter circuit, I connect it to 5V and a 20... |
H: Open Source verilog synthesizer
I'm looking for an open source verilog synthesizer. I am using Icarus Verilog as a verilog simulator. Originally I was going to use it for both simulation and synthesis, but found out the tool no longer supports synthesis. I have found the gEDA website and I have looked around there,... |
H: Is it generally possible to uniquely identify an individual MCU (for licensing purposes) (no MAC address available)
I am being asked to enhance the firmware installation program for an MCU (specifically, a Freescale MC9S12E64 - though I don't know if this matters).
The purpose of the enhanced installation is to lim... |
H: Digital Compass identifying direction of travel for use with trains
I work in a control center for a train company in the UK. Our trains work in either direction but only one end has first class carriages. Because trains on our network reverse quite a lot it is difficult for us to track and advertise where first cl... |
H: Communicating by RS-232
I'm trying to communicate with a serial barcode scanner. This is how i've linked it to my computer (the circles represent the color of the wires already soldered in the serial plug) :
http://img441.imageshack.us/img441/6126/0079.png
When I scan a barcode (a special one telling the scanner to... |
H: How can I reduce the power consumed with wall warts?
I have been designing a project that requires a 5V for some components and 12V for others. I am planning to leave this plugged in 24/7 so I want it pretty efficient. I know they don't waste that much energy, but I still want to make it as energy efficient as poss... |
H: Maximum clock frequency for multi-cycle vs pipeline
Suppose you have latencies:
IF: 10 ns
ID: 11 ns
EX: 12 ns
MEM: 13 ns
WB: 14 ns
What is the maximum possible clock frequency for a pipeline with this design? I found information online that suggests the maximum possible clock frequency is 1/c, where c is the late... |
H: 5v output to 3.3v?
I have a microcontroller and a Raspberry Pi, both running off of the same 5v supply, in parallel. The microcontroller has 4 5v output pins and the other is a Raspberry Pi, that can only accept inputs of 3.3v and less.
Obviously I cannot directly connect the outputs to the inputs - that'll fry t... |
H: How are these pcb pads made?
We want to design a pcb module that should be soldered directly onto customer pcbs (exactly like ICs ect.)
I found a module which does exactly that, please see pdf.
https://www.dropbox.com/s/ky2u9z83ja6snsh/pcb_pads.pdf
But how are these pads made i the pcb layout tool?
It looks like P... |
H: Using touchscreen cellphone lcd module for custom projects
I intend to use the capacitive touch based lcd modules of cellphones in custom embedded projects,
I will be using this display with low cost stm32 boards.
Has anybody experimented with this approach ? Any ideas, links to datasheets ?
PS : I am specifically ... |
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