An application field of electronics that requires high reliability and fail-safe systems. Application can vary widely in temperature ranges and a wide voltage range, typically 12v (or 24v) while off and higher when on.

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31 views

Error in PWM duty cycle readings [on hold]

I am working on a cruise control system. The duty cycle display 100% when the throttle controller produced both positive and negative result. I am okay with Duty cycle of 100% when throttle is ...
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1answer
50 views

12v car to mains 12v [on hold]

Hi I want to power my van with a x box transformer how can I do this? Can I leave the battery connected to the neg. And wire the neg from transformer to the body and pos to a switch swapping from the ...
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2answers
29 views

Control automotive AC switch via TPS voltage

The A/C compressor is engaged via a single wire that comes from the 'A/C' button on the dash board. I want the A/C button to disengage when the throttle is at 50%. The throttle position sensor (TPS) ...
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1answer
95 views

Converting a tachometer signal into something a microprocessor can understand

I am attempting to build a digital dashboard for my car (a 1998 honda civic), I have run into a bit of trouble, wherein the tachometer signal is quite hairy. I was wondering if someone would lend me a ...
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2answers
255 views

Automotive electrical system. How does everything work?

I recently grew a big interest into the electronic world. I also love auto/mechanics, and I’m trying to understand where these two wonderful areas meet. I’m trying to understand the fundamentals of ...
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1answer
36 views

Sense existing vehicle TPS with AVR ADC

I have an issue sensing the throttle position sensor voltage if the sensor is already being used by the vehicle's own ECM. Namely, the vehicle ECM stops responding to the throttle input after a period ...
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1answer
32 views

Automotive IO input protection design for ESD, transients, and reverse polarity compatible with ISO 7637

I want to accept an signal that could have any of the transients defined in ISO 7637-3 on it. It is a reset signal that could be tied to 24V in the case of a wiring harness meltdown but typically ...
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1answer
64 views

Connect two-function brake light to three-function car circuit

I need to replace my 12VDC (bulb based) brake lights but I am unable to find a three-function light (Running/Brake/Off) with the same specs. I did however find a two-function light LED fixture ...
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3answers
173 views

Electronic flasher with low load detection

The circuit above is an existing flasher without low load detection. I am trying to develop electronic 2-wheeler flasher with low load detection. While Googling, I got a circuit with relay in it, ...
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1answer
51 views

Is there any way to control a 12Vdc relay using 60Vdc line

I have a 60V li-ion battery back with PCM board attached to it for protection. According to the PCM datasheet, under fault condition the PCM cuts off the load and thus isolates the battery bank. The ...
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2answers
55 views

How should I understand this twin coil relay pinout? (Screenshot)

I'm currently looking on an automotive twin coil relay. The Datasheet gives me following schematic: My Question is: How could I test this relay? In other cases I put the corresponding Voltage on ...
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3answers
74 views

RGB LEDs in automotive environment with fluctuating voltage

I'm hooking up an Arduino to an automotive power supply which fluctuates between 12 and 14.4 volts. I'm also hooking up RGB LED light strips in this circuit as well, now I'm not afraid of the 14V ...
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1answer
63 views

Does it matter if I shield the antenna wire or the interference source

I have a problem. My car radio is picking up interference when ever I plug a device into the power outlet/ cig lighter. I know that the solution would be to put shielding around the antenna wire, but ...
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116 views

Does AEC-Q101 Certification mean a part has some ESD protection?

I'm working on picking out some FETs and would like to use some with ESD protection. While picking some parts out on Digikey I keep coming across datasheets that say AEC-Q101 compliant or sometimes ...
2
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0answers
178 views

Android CAN bus connectivity via Bluetooth (or USB) [closed]

I'd like to read sensor data from existing CAN buses using a bluetooth (preferably, though USB would also work) device of some sort. Trouble is, I've never done CAN bus, bluetooth or android ...
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3answers
1k views

How do the streetcars in Toronto draw power from the lines?

I've tried googling this but to no avail. I've been trying to figure out how streetcars can draw power from a short circuit. For reference: If I imagine the power lines simplified as a shorted ...
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2answers
88 views

12v capacitor / UPS system [duplicate]

I am looking to make a capacitor/UPS system for a few different electrical components in my car. I want to power the rear view camera, headrest monitors, and possibly the head unit for about 30 ...
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1answer
111 views

Detecting vehicle on parking spot

For a project we're working on we need to detect if a car is standing on a parking spot. We're using an ultrasonic sensor for this, SRF05. While using the correct timings we can only sense for about a ...
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22 views

Troubleshooting my antenna power delay

Awhile ago I build a circuit to fool my power antenna into sensing a constant voltage while I started my car. enter link description here It worked great. So installed a new power antenna and ...
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2answers
74 views

Automotive Logic Signal Switching and ESD/transient susceptibility

Sorry...can't think of a succinct question for the subject line! I am working on a project on my car. The car's existing ECU is connected to a pressure switch, which opens when the A/C refrigerant ...
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1answer
471 views

What do chips like ELM327 and STN1110 do?

What problems are the chips ELM327 and STN1110 solving? If I connect the necessary interface ICs (I mean dumb ICs, like level shifters, inverters, etc., not pre-programmed devices like ELM327) ...
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2answers
173 views

Combine two audio signals

I'm currently building an in-car alert system using a Raspberry Pi. My car has an AUX port (3.5mm jack) which I currently use with my phone - to play music. I wish to be able to play music, and play ...
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1answer
100 views

What are the components used for the iPhone-sized car hack? [closed]

Recently two security researchers hacked a car with iPhone-sized gadget according to this link. They didn't release any technical details, but I think we can guess from the picture of the gadget: ...
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1answer
73 views

How Do Vehicle Backup Sensors Work?

How do the backup sensors on vehicles work? There are 4 round sensors in the rear bumper of many vehicles to provide a backup alarm. Are they optical or ultrasonic? And what measurement principles ...
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2answers
238 views

12V Battery Backup Supply for GPRS Tracker

I have little knowledge on electronics apart from following a few guides. I have made a few 7 segment displays, nothing complicated. Recently my girlfriends car was stolen and she has an insurance ...
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3answers
558 views

How the Current Flows in a Car?

My BIG question is : why does positive battery cable in a car is directly connected to the starter to crank the engine and does that mean the current actually flows from positive battery post to ...
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2answers
140 views

How to select a power transistor to protect old school automotive ignition and headlamp switches

WAY back in my past I did some serious EE work, but not having used it for nearly 40 years, I'm a little lost on how I do this... I have some 6 and 12 v cars I'm trying to restore and was lucky ...
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1answer
87 views

Electric car control

I have a school project where I have to control the brake and accelerator of a electric car. These two are controlled by a signal and a potentiometer to vary the voltage. The problem I have is that I ...
6
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1answer
342 views

Automotive circuit works but with lots of heat. Is there a better way?

The Problem I have a vehicle that is ‘smart’ enough to detect when a trailer is attached. When a trailer is attached it changes ABS and vehicle stability control parameters, turns off the reversing ...
3
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2answers
298 views

Low-Side versus High-Side relay driving concepts

What are the pros and cons of Low-Side versus High-Side relay driving concepts in an automotive environment? The questions popped up when I was looking for an 8 channel relay driver IC for a ...
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1answer
233 views

IC to interface between digital switches (12V) and microprocessors (3.3V)

I am working on an automotive general purpose ECU where I need to interface 12V digital inputs with a µC (3.3V). The PCB space is limited, so I am searching for a single IC as an interface between ...
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0answers
1k views

How to hook up a Car Stereo for use in Home [closed]

I have a Sony cdx-gt820ip that I would like to hook up in our kitchen. I like the idea of using a car stereo in the kitchen because it has a small footprint and does everything a normal stereo would ...
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2answers
218 views

best way to detect if vehicle is running

Plan is to place in vehicle Raspberry Pi with camera. And fully automate startup/shutdown of raspberry. So - what is best way to detect that vehicle is running? ...
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1answer
111 views

car air compressor power supply unit [closed]

I want to power 12 V 180 W car air compressor from a 220 VAC source, without transformers. I want to power the pump after rectifying the 220V AC. Does that mean the pump will draw 3A or will it draw ...
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2answers
109 views

Electric vehicle power component selection help

I need your advice on high power device selection. I'm working with a similar application to this schematic, with the descriptions being in this forum. Without reading through the dozens of pages ...
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2answers
195 views

USB car charger with LED

This is related to Is it okay to keep a USB charger plugged into the cigar lighter? - I have a 12v charger that is connected to a phone dock with an integrated micro USB connector. The difference ...
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2answers
128 views

How can I charge secondary car battery? [closed]

I want to install a secondary car battery for a system/project that I am working on. However, somehow I need to be able to charge it while car is running, but not let the car modules use secondary ...
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1answer
184 views

Working around voltage drop in a classic BMW

I have an '87 BMW 535is that has had an odd electrical gremlin for years. The previous owner tried gallantly to address as have I. I am not done trying to diagnose and fix the underlying problem, but ...
4
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1answer
454 views

Using/Charging a backup battery in a 12VDC circuit

EDIT: I've revised the circuit in response to comments from Andy aka. I have also updated my questions to make it more clear what I am asking. I'm leaving the top paragraphs for completeness' sake. ...
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1answer
2k views

hard-wire 4-port usb hub to my car's 12v switched cig outlet

I would like to hard-wire a 4-port usb hub to my cig outlet. I currently have the hub connected to my power inverter and have to flip a switch to turn on the power. My goal is to do a complete ...
1
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1answer
132 views

Noise from car amp when grounded to the body [closed]

I am busy installing sound in my car. I have installed an amp and have VCC running to the battery and ground connected to the body of the car. I have noticed that there is noise, seems to be a high ...
3
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2answers
315 views

Q: ultrasonic sensors - distance detection

I have a question about ultrasonic sensors. By connecting the car parking sensor to the scope I always get the same wave. But by changing the distance from the sensor, the parking system respond as ...
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0answers
95 views

isolate switches in resistor ladder

I am looking to re-purpose some automotive switches in a project. My goal is to extend or relocate the buttons of a garage door opener to my dash board. The buttons on the dash board have 3 ...
0
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1answer
141 views

Basic DC Fan Controller

I have been tasked with retrofitting some small fans to an old car, to help move heated air into the footwells. Being a computer-type, I immediately bought some standard computer cooling fans. The ...
5
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2answers
299 views

Automotive power filtering, protection - feedback needed

I'm working on GPS tracker for automotive applications. Device should work in 9V-30V supply voltage range. In practice it will be fed from 12V car installation. This enforces the implementation of ...
2
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3answers
587 views

Electric car “J1772” charger - “pilot” signal sequencing with passive circuitry

J1772 Some background: Many electric cars are designed to use a "J1772" charging point. The main signal in the J1772 specification is called the pilot. Long story short, the car is expected to ...
2
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2answers
388 views

Arduino project, powered by car electric system

I want to assemble an Arduino project that would be powered by car, and also it should be power-independent to some degree. This project will be a simple car alarm system, with gps reciever and will ...
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66 views

What are some good resource for learning how car key and wireless door lock systems work?

I understand that most car keys include a 434MHz transmitter, as well as 125KHz RFID transponder. The 434MHz transmitter is used for operating the door locks, and the 125KHz RFID transponder is the ...
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1answer
102 views

car Battery charger (3.3V)

I have a project in mind, but i'm stuck. I want to power a board (which works on 3.3V, 13/16 mah on reception and 37 mah on emission) with a battery from a car light adapter. It seems that standard ...
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0answers
101 views

Condition Car Ignition Signal

Background: I'm working on a project that needs to accurately and quickly measure the rotational speed of the engine in my car. It is a MK3 Ford Focus, and each spark plug has a coil-on-plug that ...