-12v leads to GND?

First off, i apologize for asking so many questions. google couldnt tell me a single thing about what i wanted to know, which was how the -12v is created and why a computer needs it. so i turned to a broken power supply to see is the -12v connects to a IC of some sort, which i would assume creates the strange voltage, confirmed by a datasheet. i completely traced the traces with a multimeter and at one point a capacitor went to ground close to where the -12v connection is on the board, after an inductor of some sort. the trace continued, and lead to a pin on the transformer, much to my disappointment. BUT that same trace was directly connected to ground, so now i am confused, does the inductor type piece createthe -12v? there was a diode as well, but i thought nothing of it or its place on the board.. i have a feeling i should have, shouldnt i? fed up and confused by the power supply, i turned to my motherboard. where the -12v leads to a smd capacitor and then traces from the capacitor, to ground, and nowhere else as far as i can tell with a multimeter and a dark blue motherboard. then i bring up the picoPSU, how do they make the -12v, if it is even made? is there a chip responsible? or a inductor like i found in the power supply? -5v has been omitted form power supplies, so im assuming that the same can be done by -12v, right? and wouldnt you get a -v type measurement if you put the + test lead on the - terminal and vice versa?

Question by zack247 7 years ago  |  last reply 7 years ago


what's the difference between -12V and GND? Answered

first, i thought that if some electronics said -X V, it was just GND, but then i saw both in the same circuit,  so what's the difference? and how can you use -12V

Question by godofal 8 years ago  |  last reply 1 year ago


How to make a small ground? Answered

I want to make a lightsaber from a 18w neon tube. I am using a 12v to 1800v inverter. The positive lead is connected at the bottom of the tube but in need a ground on the top without pulling a wire from the inverter.

Question by theVader75 8 years ago  |  last reply 8 years ago


Is there a difference in the Gnd pins on an Arduino Duemilanove?

I am working on an Instructable where it instructs you to connect the Negative wires from two servos and a Ping sensor to Gnd. Can I connect all three to the same Gnd? Also, is there a difference between the two Gnds on an Arduino Duemilanove? Which Gnd should I connect them to?

Question by 9 years ago  |  last reply 9 years ago


Can i connect input to GND ? Answered

Hello, i have a little amp based on this layout : My question is : when i need to temporary disable the input, can i connect "IN" to GND ? Thanks for advance!

Question by login721 7 years ago  |  last reply 7 years ago


Broken GND button on Stanton turntable

Anyone run into this problem? How to fix please thanks

Topic by hoolia711 1 year ago  |  last reply 1 year ago


Intel PIII processor GND and voltage pins?

 I am making the hot plate found at: www.instructables.com/id/Hot-Plate/ I want to find the 'voltage' and 'gnd' pins for my Pentium 3 SL4MF processor. The datasheet at: download.intel.com/design/PentiumIII/datashts/24526408.pdfshows the pinout, but I can't figure out which pins to connect the wires to. Please Help. Kabir

Question by mhkabir 9 years ago  |  last reply 9 years ago


continuity between 3.33v and gnd on atx psu?

Im converting my atx into a bench psu. I was checking the continuity between 5v and gnd that i connected to the LTC3780 and i got a beep (one short beep). So i checked the rest of the lines and 5v and 12v also 1 short beep. However on the 3.3v. i get  a long continuous beep. Is this behaviour to be expected?  thank you in advance.

Question by icey.hood 1 year ago  |  last reply 1 year ago


3 wire interface (GND, VCC, DATA)? Answered

Hi guys,   I'm trying to reverse the communications on a project I have at the moment which seems to be using a 3 wire serial interface (GND, VCC, DATA).  My goal would be to replicate the communications with an arduino or similar, however i'm not 100% sure what serial protocol it's using.   The device is using an Atmel ATMEGA168 and the pcb is covered in conformal coating, so I haven't had a whole lot of luck tracing the pins. I'm not overly aware of many one-wire communications protocols.  The datasheet says the ATMEGA supports various peripheral features, including SPI, USART, 2-wire serial (Philips I2C) (among others), however the GND, VCC, DATA configuration doesn't seem to fit with any of the supported protocols (i.e. there's no clock line and only a single data line).   The captures i'm getting seem to indicate that it's an 8-bit binary protocol.  I was going to try to decode it manually and attempt to reproduce it, however would be grateful if someone recognizes it and can point me in the right direction. Does anyone know any protocols / configurations this could be?  Example screenshot attached. Any help would be greatly appreciated!  Thanks!

Question by ikarus6 3 years ago  |  last reply 3 years ago


I broke an LED; will connecting the one wire leading in to the wire leading out break the device?

I have a broken LED. Will connecting the wire leading into the LED to the wire leading out of that one LED break the device? I don't have solder so my plan was to twist together the stripped wires and wrap in electrical tape. Would powering on the device cause any sparks? The LED is part of a group of LEDs in a ring around the cone of a hair dryer. There are wires leading up to this ring-shaped circuit board with six leads and a resistor. Would directly connecting the two wires leading up to this ring-shaped board break anything or potentially be hazardous if operating the hair dryer? Now that I think about it, the electrical tape would not be a good idea as it would probably melt pics: http://i.imgur.com/pSmSvUc.jpg http://i.imgur.com/X7GUoDn.jpg

Question by guyersky 2 years ago  |  last reply 2 years ago


What are the "ground" on a electronic circuit? Answered

I have checked many schematics and on all of them I see GND (ground) and nothing going to the VSS of the power supply. Is GND mean that it's connected to the negative (VSS) or is it more complex than that? What I am supposed to do if a schematic have both negative and grounding? Thank you.

Question by sxdemon 9 years ago  |  last reply 9 years ago


Confusion about ipod GND connection; how many?

Hi everybody :)I'm a bit confused about something and I thought some of you might know the answer. When looking at the ipod pinouts at http://pinouts.ru/PortableDevices/ipod_pinout.shtml there are several different GND connections. The thing I need to know is this: are all these connections the same? Is there one common ground?ThanksDaniel

Topic by Twellmann 9 years ago


eagle - how to get thicker traces for gnd and power

Hello, Can someone please tell me how to easily get thick traces for gnd and power. I created the schematic and autorouted and all the traces look the same width. Thanks. PS. Also, How do I put some text on the pcb without getting an error about the font - no vector font?

Topic by thegruffalo 11 years ago  |  last reply 11 years ago


How to supply voltage to a circuit which requirs +12v, +5v and GND

I need to know how to supply voltage to a circuit which requirs +12v, +5v and GND. The circuit is a Pic Programmer. Im sorry if this is a stupid question, but im kinda new to electronics and would appreciate any help provided. Please look at the circuit attached below. Thanx

Topic by omega69 7 years ago  |  last reply 7 years ago


Voltage rail identification on LCD PCB

I am testing the DC rails coming off an LCD TV PSU so i can convert the unit to run off an ATX PSU. i have managed to find (labelled on the board) 12v, 12v, NC, GND, GND, GND, ?, ?  the last two aren't  labelled. the two pins (when tested to GND) are giving me -12v, could this be right? I'm guessing by this point ill just have to use the 12v rails, GND and -12v from the ATX to get this powered?  what else could those last two pins be? 

Topic by andrewlapham2010 1 year ago


Why won't my code work?!

Howdy! I am fairly new to basic ARduino programming and have small project in the works. In order to re-familiarize myself to coding for Arduino, I am simply trying to make an LED turn off and on when an SPST switch is flipped. Simple right? Yeah, no. I have included my code below. The problem I have is on start, the LED lights up and stays on! When I hit the switch, it just gets brighter. Funny thing, if I connect the switch to the GND pin, the LED can be controlled- but in and opposite manner. Also, when using GND, the LED may turn off or on, but every now and then, it will turn on or off- depending on what state its' in. FYI, I'm using an Arduino Mega 2560. Thanks for the help! const int led_1 = 31;       //LED cathode is connected to PIN 31 and anode to GND const int switch_1 = 44;       //Single SPST switch is connected to PIN 44 and the 5V pin int switch_1_State = 0;       //Initial "switch_1_State" is LOW void setup() {   pinMode(led_1, OUTPUT);       //led_1 is set as an OUTPUT   pinMode(switch_1, INPUT);       //switch_1 is set as an INPUT } void loop () {   switch_1_State = digitalRead(switch_1);       //Read state of switch and store in "switch_1_State." Will either be a HIGH or LOW   digitalWrite(led_1, switch_1_State);       //Tell led_1 to either be HIGH or LOW depending on state of "switch_1_State" } //Problem is LED is always lit. When turning the switch to the "ON" position, the LED just becomes a little bit brighter. When turning to "OFF," LED just dims slightly. //If switch is connected to GND instead of 5V, LED turns off an on sporatically, opposite to the switch's ON and OFF state. Explain?

Question by shooternash 5 years ago  |  last reply 5 years ago


Measuring a Bluetooth modules output? Answered

There is a serial Bluetooth module that I have used before on an Arduino project but now I'm trying to use in a project without the Arduino. Basically I need it to be an electronic trigger, I don't care really what the signal is just how long and the voltage and current. There are 4 pins on the module: Vcc, GND, Tx, and Rx. There are 2 open pads: Key and State. When I send a command from my phone the module sends a signal out the Tx pin, and it is this signal I would like to measure so I can pick a command with an appropriate signal and tailor the rest of the circuit accordingly. I tried a voltmeter between Tx and GND but saw no signal on any level measuring DC. Is there something I'm missing? Is the signal more complex or different, or is that test setup flawed? I tried other combinations, Rx-GND, Tx-Rx, RX-Tx, GND-Tx, GND-Rx but saw nothing.

Question by bwrussell 6 years ago  |  last reply 6 years ago


i have got this thing off ebay just need a clue how to connect something to it? Answered

I have a small amp PCB off ebay it has the connectors down the side for the points to connects the parts to it but i just cant work out the connect or plug into the device what i have so far is R+          Speaker right R-           Speaker  right L+           Speaker left L-            Speaker left gnd        power +5v         power sw          switch gnd         switch lin gnd rin thanks for any help you can offer

Question by nonamesleft 5 years ago  |  last reply 5 years ago


Problems with my arduino mini shield

So i built an arduino mini shield for displaying numbers(i used the 4511 bcd to 7 segment decoder ic ) using only 4 pins excluding v+ and v-(power).It seemed to work well for while but later when i tried displaying 0001 ( 1 in binary) ,it suddenly stopped working or some all the segments got dimly lit . .Also if i plug it into the breadboard and connect some jumpers to the pins of the arduino(+5v and gnd) ,it seems to work fine,however when i plug it directly into the arduino,setting pin13 high and the gnd pin near it ,it does'nt work properly and all the segments glow dimly.The control pins for the digits are pin 12,11,10 and 9.also when i plug it into the breadboard and instead of connecting the pins with jumpers to +5v and gnd of the arduino,if i connect it to pin 13(HIGH) and the gnd near it it displays only 8, also can't i use pin 13 being HIGH as 5v' s? WHAT AM  I SUPPOSED TO DO?

Question by Strontium 5 years ago  |  last reply 5 years ago


Need help with DS18B20 1-wire thermometer IC

So I recently bought a DS18B20 1-wire digital thermometer IC to use with an arduino.  But when I hooked it up, I couldn't get any reading at all out of it.  I have the VDD pin wired to 5v on the arduino, the gnd wired to gnd, and the data pin wired to analog pin 0.  Any help would be awesome.

Topic by dudes 4 years ago  |  last reply 4 years ago


L293D with 12V motor issue? Answered

Hi,All Now i wanted to control a 12V motor with a L293D chip.my purpose is to make the motor go forward and reverse with the control of Arduino.I got a wiring from internet.but I think is incomplete wiring.the arduino uses 5v power rail and the motor uses 12v power rail.from the wiring i cannot find the GND with the 12V power.so strange.i want to know how the 12V rail GND wire goes? Shanno.G

Question by gada888 3 years ago  |  last reply 3 years ago


I need a simple curcuit ?

I need to turn on a 24vdc relay (apply gnd ) with a transistor. I have a 5v signal as the sourse from an industrial computer

Question by daveaprile 5 years ago  |  last reply 5 years ago


pinouts of an mp3 player module? Answered

I have an mp3 player module whch i took out from a home theatre main unit. I want to know the use of some features or the pins which are given in it because i am a beginner to electronics and stuff. I am using it as a player using headphones because it needs amplifier to play in speakers, but headphones work with medium sound. It has usb and sd card port for input. Also have 3 pushbuttons , play pause, next , previous. It has the following pinouts. Basic ones which I know: +5v  GND L_OUT R_OUT These must be for pushbuttons: P4.1 GND P4.2 P1.2 P4.4 (but there are only 3 buttons)??? IR (this could be infrared remote control) These I want to know what are for??? +5v GND SDA     SCL P5.7 RST

Question by akki5230 4 years ago  |  last reply 4 years ago


Cheap amplifier board, what do all the connections mean please

I bought a cheap amplifier board based on the PAM8403 chiphttps://www.amazon.co.uk/dp/B075L9TVHB/ref=cm_cr_r...most of the connections make sense, from top to bottom in the main picture, two speakers, then power, then sw and gnd, followed by the left right ground which I assume is stereo input.I have no idea what the SW and GND refer to, can anyone help me out here?

Topic by oragamiunicorn 1 year ago  |  last reply 1 year ago


Connect Arduino UNO to a Laser with TCP/IP or RS232 protocol

Hi everyone, I am trying to comunicate with a Laser via ethernet or RS232 but I realy don't find enough information in internet to make my sketch. For TCP/IP, I am using a ENC28J60.CLK ---> D8SO ---> D12SCK --->D13SI --->D11CS --->D10VCC --->3,3vGND --->GNDYou will find attached the manual for TCP/IP comunications that the laser company gave me.Finaly for RS232, I tried to use the TTL-RS232 module (MAX3232) to comunicate but I was not able to make it works. (attached the manual for RS232 comunications that the laser company gave me.RXD ---> RX 0 TXD ---> TX 1VCC ---> 5vGNS ---> GNDPlease could somebody helps me with the code. Thank you,Jonathan

Topic by JonathanP233 7 months ago  |  last reply 6 months ago


how to make digital potentiometer as mechanical potentiometor using arduino?

 connection between digital pot x9c103p  INC - Arduino pin * U/D - Arduino pin 3 * VH  - 5V *VSS - GND *  VW  - Output: 150 Ohm resistor -> LED -> GND *  VL  - GND *  CS  - Arduino pin 4 *  VCC - 5V and the code i used #include DigiPot pot(2,3,4); void setup() {   Serial.begin(115200); } void loop() {   Serial.println("Starting");    for (int i=0; i<100; i++) {     Serial.print("Increasing, i = ");     Serial.println(i, DEC);     pot.increase(1);     delay(200);   }   for (int i=0; i<100; i++) {     Serial.print("Decreasing, i = ");     Serial.println(i, DEC);     pot.decrease(1);     delay(200);   } } what is error in that and how can i make sthing varry between 1k to 4k if i have digital potentiometer 10k

Question by britich 5 years ago  |  last reply 5 years ago


Can anyone help me program this 8x1 LCD with Arduino?

I'm having trouble programming this 8x1 character LCD. It's not compatible with the Arduino's LiquidCrystal library. The manufacturer failed to give a detailed datasheet. This is the supplier of the product: click Here's the Pin Map (according to supplier) : 1.) Gnd 2.) VDD (3.3v) 3.) CS Input 4.) SCL - clock signal input 5.) SI - data input 6.) /RES - reset signal 7.) Backlight Anode (3.3v) 8.) Backlight Cathode (Gnd)

Question by ASCAS 4 years ago  |  last reply 4 years ago


CH340G and Standalone UNO R3 Got ERROR "avrdude.exe: stk500_getsync(): not in sync: resp=0x00?"

I bough the CH340G USB-TTL with 6 pin (GND, CTS, VCC, TX, RX, DTR). The CH340 driver already installed, the arduino bootloader also already burn to ATmega328P-PU. When upload the sketch using FTDI or PL2303 or ATmega16U2 is okey and no error found. But if Ia using CH340 and connecteed below pin: Arduino VCC ==> VCC CH340 Arduino GND ==> GND CH340 Arduino RX ==> TX CH340 Arduino TX ==> RX CH340 Arduino RESET ==> DTR CH340 The error always appear as "avrdude.exe: stk500_getsync(): not in sync: resp=0x00?" event the speed on the port setting already change at 9600; 19200 or 115200. Iam also trying with IDE 1.6.0, 1.0.5 and 022 the error message are same. May be someone can help me please?

Question by wachid_elektronik 3 years ago  |  last reply 3 years ago


RW67tx-na03 200607-001 video transmitter

Want to connect a 2.4 Ghz RW67TX-Na03 200607-001 to a camera with VDD and GND Video. But I can not find a wiring diagram. please help !!!!!

Question by Dannne11 8 years ago  |  last reply 8 years ago


Where to connect the Syma x11C camera box?

So i have a bunch of spare parts that i've obtained from working at an rc shop. In this is the receiver board and camera box of a Syma x11C quadcopter. They were connected at one point, but i remember a friend destroying it on accident a while back, so i know these were the same parts. I am just curious as to where to connect the camera box to the receiver board (the camera box still has red,black,yellow wires attached to +,gnd,DV respectively.)  Is it possibly to the DATA,GND,VCC on the front right of the receiver board?

Question by seans42 3 years ago  |  last reply 3 years ago


mobile camera to pc

I have a nokia 3110c camera i detached from the board i want to connect it with pc and without the phone board and i want to know the pinout (v+, Gnd, D+, D-) ? please Help

Topic by MinaN7 2 years ago  |  last reply 2 years ago


GBA sp ribbon pins: What does these do????????

I know the ribbon pins of the GBA sp AGS-101 backlit screen,(there are 34 pins total) and I want to hook up the pins to a vga cable to connect to the tv/monitor, (and I know how to connect the audio, that's not a problem) but the problem is, I don't know what these pins are, or do? Please help, there is a picture of a vga diagram.( I am trying to make a GBA sp Console) 1 - VSHD 2 - DCK 3 - LP 4 - PS 5 - VSHD 6 - GND 7 - LDR5 8 - LDR4 9 - LDR3 10 - LDR2 11 - LDR1 12 - LDG5 13 - LDG4 14 - LDG3 15 - LDG2 16 - LDG1 17 - GND 18 - LDB5 19 - LDB4 20 - LDB3 21 - LDB2 22 - LDB1 23 - SPL 24 - CLS 25 - SPS 26 - MOD 27 - REVC 28 - P2-VDD 29 - P2-VSS 30 - COM 31 - VDD5 32 - GND 33 - ??? (U83 on AGS-001) 34 - VDD5

Question by 8BITR 2 years ago  |  last reply 2 years ago


How to build a 12v to 5v conversor with a zener?

I'm developing a shield for my Arduino Uno and I want to add in it an external power supply. The power source I want to plug in it has four connectors: 5v, gnd, gnd and 12v. The 5v and the gnd pin goes to their respective pins in Arduino, while the 12v pin goes to a 7805 on the shield or to Vin, and the selection is made with a jumper. The only problem is that the connector can be plugged inverted, swapping 5v and 12, which would damage the AT mega. I know zener diodes are useful for limiting power, but I don't know how to use it. I need a simple circuit in which I can plug my 5v supply and it gets 5v to the chip, and in case I plug the connector inverted, to limit its power to 5v to prevent damage or to shut down the power. I can’t use the 7805 on both pins, because it would deliver something like 4v or less if powered with 5v. And something like a led to indicate that the connector is at a wrong position would be nice too. Thank you.

Question by senitram 4 years ago  |  last reply 2 years ago


Arduino and esp8266

Hi, I am new to arduino and creating project where i connected arduino uno and esp8266 as follows: UNO --- ESP8266 RX ----- RX TX ----- TX GND --- GND 3.3V --- VCC 3.3V --- CH_PD I power arduino uno and it is working fine. i checked by uploading blink program. when i connect esp8266 to arduino uno and open serial monitor i am getting some garbage text which is shown in below screen shot. also when i connect esp8266 to uno the orange light is continuously blinking. no action on entering AT command in serial monitor. some one please let me know how to get it work.

Topic by sayedfar 3 years ago  |  last reply 3 years ago


'Can I connect 2 TPA3118 60w Mono Module to create a Stereo Amplifier?'

This is the only amplifier I had lying around and since it was a mono amplifier, it only accepts 2 inputs. By using two boards at the same time feeding the same signal wherein the LEFT channel and GND goes to the 1st board and the RIGHT channel and same GND to the second board will it work smoothly as a stereo amplifier creating a 120w Amplifier? ~(Also, I'm using only 1 power supply to power the two boards.)

Topic by Chloe_Lemaire 1 year ago  |  last reply 1 year ago


connecting new ping to arduino. Answered

Hi, I got ping from amazon but it has 4 leads and I do not know how to connect it to the arduino. The leads say vcc, trig, echo, and gnd. Will I be able to use the examples with ping on my arduino?  http://www.amazon.com/gp/product/B004U8TOE6/ref=oh_details_o00_s00_i00

Question by jbaker22 6 years ago  |  last reply 6 years ago


HI! I have a USB To TTL board. Can i program avr atmega(atmega168) and pic16f series(pic16f72) microcontrollers with it?

Can i simply use 5v, gnd, RXD, TXD pin for programming? My boards image is attached with this question.

Question by ddeepu 5 years ago  |  last reply 5 years ago


How to control Stepper Motor with Integrated Controller, with Arduino

I salvaged a few big stepper motors from a large Laser printer. Unfortunately they all have integrated controller boards. I would like to control them with an arduino. I am aware that an option is to remove the PCB then use a regular contoller. I would prefer to use the integrated board. The boards have the following inputs: 24V GND P/S LD CLK +5 GND The high and low voltage and ground are obvious. CLK is the clock speed (which I half understand). LD is Load?? P/S is pulse?? The board has an SLA6024 with a nice heatsink. (perhaps that helps. I am after a wiring diagram and arduino sketch to control the motor for a CNC machine. Your help is appreciated. Attached are a few images.

Topic by craigevert 7 years ago  |  last reply 5 years ago


what if my arduino quit working and doesn't power an led on pin 13?

It still lights up but the led that i put on gnd and pin 13 won't light up specificall ythe fade function isn't working but blink works I don't know why can someone help me?#

Question by nerd7473 6 years ago  |  last reply 6 years ago


How do I "unbrick" the Electronic Brick shield? Answered

I'm trying to connect external sensors (in the picture below - 2 tilt switches), to an Electronic brick shield like this (see picture): I extend 2 buckled plugs from the shield with male-to-male headers. As far as I can understand from their cookbook - white supplies gnd, red gives +5v, and black is the signal - so I take the gnd and +5v from *one* of these cables and connect them to the breadboard's -/+ busses. Black goes to the switch (and to gnd via a pul-up resistor). The second switch takes +5v from its plug's red line (could also take it from the bus - but it looks neater this way), The other side of the switch goes to the black line (yellow jumper). This setup simply turns off the Arduino (short-circuit?). Pulling out the buckled plugs turns it on again. This tilt switch setup is pretty simple (I've tested it without the Electronic brick shield - sending the inputs from them to LEDs - and it works fine). I've also tried "unbricking" the LCD brick itself (That's what I'm really after) by sticking jumpers into the holes in the bus cable (according to what I've gathered from the Electronic Brick cookbook), and I couldn't get it to show anything or turn on the backlight. Is there some voodoo I'm missing here? Thanks.

Question by thedod 8 years ago  |  last reply 8 years ago


Help with a game system mod?

I'm buying a sega game gear to mod. I want to add an a/v input without using the tv tuner accessory. Is this possible? I cant find it anywhere online, but i did find a pinout and it seems possible. I know i could connect the audio to pins 44 and 45. Would it work if i connected the video in to pin 43? Any help would be appreciated. Thanks in advance. 1 +34(V) liquid drive                                        24 MREQ memory request 2 +5(V) +5(V)                                                    25 A10/TPR2 address 3 /WR write signal                                           26 /RD read signal 4 A12 address                                                 27 /EXM 2 0~7FFFH 5 A7/CL1B3 address                                      28 A15 address 6 A6/CL1A2 address                                      29 A11 address 7 A5/CL1B2 address                                      30 A9/TPR1 address 8 A4/CL1A1 address                                      31 A8/CLIA3 address 9 A3/CL1B1 address                                      32 A13 address 10 A2/DW address                                          33 A14 address 11 A1/DO3 address                                        34 /EXM1 8000~BFFFH 12 A0/DO1 address                                        35 +5v +5 volts 13 D0/DB data                                                 36 /M1 M1 cycle 14 D1/P3 data                                                  37 IORQ I/O request 15 D2/P2 data                                                  38 /RFSH refresh 16 GND D ground                                           39 /RESET Reset 17 GND A ground                                            40 CCLK Clock 18 GND D ground                                           41 GND Ground 19 D3/P4 data                                                  42 /GG MS/GG 20 D4/P1 data                                                  43 /TV TV Cart 21 D5/CL2 data                                               44 TVSNDR VR Right Audio 22 D6/DO2 data                                              45 TVSNDL TV Left Audio 23 D7/DO4 data

Question by musick_08 7 years ago  |  last reply 7 years ago


Will this 'switching' circuit work for cabinet lights? Any comments?

Im making cabinet lights using LEDs. I use a transformer to power it off AC mains, but I want it to run on batteries too... So Im making a circuit that would automatically change the source of the power from the mains to battery when the power goes out, and back again when it comes on. Im using an NPN and a PNP transistor to do the switching. When mains (S1) is on, the NPN is on and current flows from the transformer, when S1 is off, NPN is off and PNP is on and current flows from the batteries. What I am worried about is that (I think) the transistors need a Gnd on the emitter. Is that right? If I connect the +ve of LEDs to [OUT] and -ve to GND will it work as expected? Can someone try please?

Question by pro2xy 7 years ago  |  last reply 7 years ago


Problems With My HXT HX5010 servo.

I recently bought a HXT  HX5010  twin bearing servo.First it did'nt work when i tried powering it off the arduino ,so i switched to a separate power supply and connected the gnd of the power supply to the gnd of the arduino and then it started behaving better.When i ran the "sweep" program on the arduino the servo started sweeping however i noticed that it did only around-about 160 degrees and not a full 180 degree sweep.Even when the servo tried to do a full 180 degree sweep,as it reached the far end(180 degrees) it would lock itself and not move and a low grinding sound would be emitted from the servo after it got locked.Does my servo have bad gears?,should i lubricate them?This is the first time i've ever used a servo ,so please help me out!

Question by Strontium 5 years ago  |  last reply 5 years ago


Add Internal battery to Craig Bluetooth speaker?

I have a Craig CHT913 Bluetooth speaker that must be plugged in to operate. I have a picture of the min board attached and was wondering if someone can tell me if the two solder points labeled '3.7v' and 'GND' are for a backup battery? how can I test to ensure that this is what it is for without ruining the board?

Question by shad626 3 years ago  |  last reply 3 years ago


How to find read pinout of a flyback transformer?

Hello, everyone. I have a picture of the flyback transformer pinout on the circuit board. I was wondering if someone could confirm that the +14v and -14v are for the primary coils and the GND is 0v of the secondary. Thanks. Any other info is very much welcome =) picture: http://www.flickr.com/photos/100764000@N03/9587380434/

Question by raccoondog 5 years ago  |  last reply 5 years ago


What are the "Enable Input" pins on a decoder? Answered

I'm trying to multiplex with an arduino and a 74HC238N decoder. on the datasheet I was looking at I saw that besides the 8 outputs, 3 inputs, GND and Vcc there were also 3 "Inable Input" pins, that I couldn't figure out what they do. Can somebody please explain? Thanks. 

Question by yonch 5 years ago  |  last reply 5 years ago


Do you have to turn an Arduino on\off?

I am new to Arduino and was wondering about power consumption. Do you turn an Arduino off\on? Also, when hooking up a battery, under "Power", you hook up negative to Gnd, and positive to Vin or 5v? Finally, where can you find the cable to hook a Duemilanove to to a computer?

Question by 9 years ago  |  last reply 9 years ago


Can't properly flash Attiny85, please help.

I have working proto of a bathroom exhaust fan controlled by methane sensor via arduino uno. I now wish to transfer this sketch to an ATtiny85 (cause i had extras). I have programmed ATtiny before, and can successfully get 'blink' going on this specific MCU. However I cannot get my sensor sketch to work properly... Perhaps I am asking too much of this little guy? I am including my code and video in hopes that someone can steer me in the right direction.  /*   AT85      Arduino    Circuit   0 (PB5)   A0             pin 3 of 50k pot   2 (PB7)   ~9             led or relay     Trim Pot        1              GND   2              GND   3              Arduino (attiny) & Sensor B1     Sensor   A1             +5VDC   H1             GND   GND            GND   B1             Trim Pot 3   */   const int numReadings = 10;    // average sensor reading used from 10 samples int ledPin = 1;                  // replaced ac/dc relay with led to debug int readings[numReadings];      // the readings from the analog input int index = 0;                  // the index of the current reading int total = 0;                  // the running total int average = 0;                // the average int inputPin = 0;    //reading from sensor unsigned long start_time; unsigned long current_time; unsigned long elapsed_time; void setup() {   // sets digital pin 1 to output   pinMode(ledPin, OUTPUT);     // sets analog 0 to input   pinMode(inputPin, INPUT);   // initialize all the readings to 0:   for (int thisReading = 0; thisReading < numReadings; thisReading++)     readings[thisReading] = 0;          } void loop() {         // 10 sample average used to prevent false positive from a bounce and/or spike         // subtract the last reading:   total= total - readings[index];           // read from the sensor:    readings[index] = analogRead(inputPin);   // add the reading to the total:   total= total + readings[index];         // advance to the next position in the array:    index = index + 1;                      // if we're at the end of the array...   if (index >= numReadings)                  // ...wrap around to the beginning:     index = 0;                             // calculate the average:   average = total / numReadings;           // send it to the computer as ASCII digits          delay(1000); // delay in between reads for stability                    int threshold = 300;                  // sets the threshold value   if(average > threshold){  // determines if the level of methane breaks threshold         start_time = millis();      // starts exhaust fan on 5 min timer     digitalWrite(ledPin, HIGH);      do  {       current_time = millis();      // defines the 5 minute timer       elapsed_time = current_time - start_time;     }     while(elapsed_time < 300000); // 5 min. countdown   }     if(average < threshold){      // sensor is checked against threshold       digitalWrite(ledPin, LOW);  // fan turns off if sensor value below threshold     }                             // or stays on until it is below threshold     } http://youtu.be/cm_uuEXd8HM thanks in advance!

Question by earthtown 6 years ago  |  last reply 6 years ago


How do you hook up a battery to an Arduino?

I am making a circuit out of an Arduino Duemilanove and a 9v battery. To hook up the battery, you connect negative to Gnd under "power", but where does positive go? Vin, or 5v? I want to power other components (motors, LEDs, etc.) with the battery too. How can I access the power?

Question by 9 years ago  |  last reply 9 years ago


How to set up a 7 segment display on an Arduino ?

 How would i set it up for this display? on the left side each pin is labeled from top to bottom D0 D1 D2 D3 and Digit on right side Top to bottom +9v+5v and GND (1st Pic)  The send Pic is just the bottom of the display. PLZ HELP Thanks!

Question by Dylan552 9 years ago  |  last reply 9 years ago