Questions tagged [automotive]

Questions about the design of electronics for use in an automotive environment. (Questions about the installation and use of automotive electronics are unlikely to be appropriate for this site.)

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2answers
104 views

Count car weels without using visible light (camera/laser etc) and without interaction [closed]

For this project we need to count weels of a car (if possible at all), one side only. The scenario is within the following scope: The car is always passing in a straight line It is cars only, so all ...
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1answer
158 views

Identifying VW head-unit connector types

I've kind of been on a long quest to build an embedded system for working with the head unit of my '04 VW Golf. Others have done some work to detail pin-outs and write source code to send signals to ...
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2answers
777 views

Automotive load dump protection with TVS diodes

In this marketing material by Littlefuse they explain how to use e.g. their TPSMA6L TVS diode for automotive load dump protection: TVS Diodes can provide secondary transient voltage protection ...
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3answers
2k views

Alternator current when charging flat battery

I've found some voltage-current-rpm graphs for car alternators and did not quite understand one thing. Basically, my alternator is rated at 75A (small car), which it should output above 2000 RPM or so....
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3answers
130 views

Sensor damage, ground loop or something else?

We are testing an capacitive fuel level sensor in field. Its mounted on top of a heavy construction vehicle (colmar) with a 24v battery system. Our sensor runs for few weeks and damages. Every time a ...
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1answer
97 views

Automotive power steering unit connector identification

I would like to request some help to identify the following connector (at least the manufacturer and connector family type): located inside the Toyota Camry 2018 Hybrid Power Steering Rack Pinion (...
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1answer
181 views

I need help to solve my melting switch problem [closed]

I have used a 20A 12VDC switch which by-passes my air-conditioning climate switch in the car which is not functioning, and yes... The 20A melted. My car battery is 12V. I have a glass fuse installed ...
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1answer
2k views

12v relay latching until no power [duplicate]

So I'm awaiting to wire in one or two relays so that a circuit is not powered until a push button is pressed. Then the circuit remains powered until total power is turned off. I've been trying to ...
0
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1answer
39 views

Powering dual 5VDC, 2.4A USB ports via a switch in vehicle

I have an illuminated 2 port usb charger that plugs into a cigarette lighter/accessory socket in a car. The face of the charger is flat and sits flush when inserted into the cigarette lighter/...
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0answers
497 views

Autofeel light bar mod [duplicate]

I purchased an Autofeel 30 inch light bar that has 4 rows of LEDs. I have seen this bar advertised under a number of different names, but as far as I know it's the only one with 4 rows of LEDs (they ...
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2answers
158 views

OBDII Car-Hacking

Can I implement an OBD-II scanner using an ATMEGA328P in place of the ELM 327? Preferably read some diagnostics code and upload that data to a web app via mqtt using GSM module.
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1answer
209 views

PCB connector identification

appreciate if anyone is able to help to identify this connector in the photo below. Basically i am trying to identify different types of connectors/ports around different PCB to find debug ports. ...
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1answer
289 views

Can car alternator back-emf damage electronics?

I know on startup a motor or generator produces back-emf and current ( correct me if I'm wrong, been a while since I've worked with electric machinery ). Thus, it'd be reasonable to expect that when ...
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1answer
170 views

Diodes needed (parts) for OR gate automotive relay circuit

I need to power up a make-or-break simple automotive relay (4pin, 40A 12V) via an OR gate. OR gate as follows: Source 1 is the cable that provides +12V to activate car dome light which I will tap ...
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1answer
170 views

Powering a Behringer MicroMIX MX400 - Car Audio Application [closed]

I am installing a car audio system that will have TWO aux inputs; one in the dash and one in the rear passanger seat are. I decided to purchase the Behringer MicroMIX MX400 mixer. The power spec for ...
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1answer
45 views

TWO 3.5mm AUX sockets to ONE 3.5 AUX plug - Car Audio Application

I am putting together a car audio system and replacing the factory stereo with a new aftermarket head unit that has a single aux input. The vehicle comes with a single OEM aux input jack in the dash. ...
0
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1answer
65 views

High side driver internal design

I have a question about the high side driver VN7016AJ for automotive applications, during ISO pulse1 -150 V will be applied at its VCC pin, I found from the User manual (UM1922) that when -150 V is ...
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1answer
48 views

Connector identification (multipin connector for automotive touchscreen)

This connector is from a device connected to the touch screen in the car. This device is chinese, so I'm having trouble locating information about any part number or name. The connector has 4 wires ...
2
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1answer
2k views

How many horsepower does an alternator take from an engine at different speeds? [closed]

I want to know how much horsepower the engine deliver to the alternator at idle rpm,normal rpm and maximum rpm
1
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1answer
408 views

How short circuit is made when connecting negative cable first when jumping start the vehicle

When Jumping start, I understand that I need to connect the positive terminal first due to the safety reason. And also if I connect negative terminal first and touching the body of the vehicle with ...
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5answers
612 views

Can I derive steering wheel angle of a car from gyroscope data (x,y,z values)? [closed]

I am not an electrical engineer but I don't really know where to ask this question so here it is. I have some x,y,z gyroscope data from a car and I want to calculate the steering wheel angle at a ...
1
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1answer
176 views

What is the use of series resistor in VBAT line of CAN transceiver?

In the application diagram CAN Transceiver TJA1043 (Page – 19), there is a series resistor in the VBAT line. What is the use of this resistor? How to select the value for this resistor?
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1answer
92 views

Using a Small Signal Relay in Automotive Application

I want to implement a 12V relay (https://www.mouser.com/ProductDetail/Panasonic-Industrial-Devices/TX2SA-12V?qs=HLLy2pIPwuuBcCVwky7PWw%3D%3D) in an automotive application. I will be using the car's ...
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2answers
104 views

Swap between two colors without an additional light?

A Quick Note I'm not sure of a more accurate name for this question. If you can think of a better name, feel free to edit and change the name. Also, I'm not the greatest with technical terminology so ...
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1answer
74 views

Two capacitors of same value connected in series and connected to power supply instead of one capacitor of equivalent value for PCB design

what's the purpose of two capacitors of same value connected in series and connected to power supply instead of one capacitor of equivalent value for PCB design especially for Automotive applications
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1answer
1k views

Would you get electrocuted if you touched a car battery? [duplicate]

Lets say that you have a connected car battery. If you remove the negative lead first and then touched it would the current go through you to the earth (GND)? What is i then attached a wire which is ...
2
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3answers
449 views

Designing brake light with specific luminous intensity

I am currently designing a brake light for a Formula Student car and I am looking into existing solutions on the market for inspiration. The two specific solutions are this, and this. The LED I found ...
3
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7answers
2k views

Opinions on what I've come up with for a 12 V-to-5 V automotive circuit?

Is this a solid solution for an automotive 12 V-to-5 V circuit to power an ATtiny? I've been trying to come up with a solution for my needs that can handle the automotive environment that is so scary ...
4
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6answers
1k views

Can an EEPROM be one-time-programmable?

I'm confused, and I hope you can help me figuring out, what I misunderstood. I am not an electronics engineer, so bear with me :) I have a chip, from the engine control unit of a Toyota Yaris Verso ...
1
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2answers
153 views

How can I sense a signal on a 12v automotive wire non invasively?

I'm working on a project where I need to sense if a circuit is in operation on a wide range of vehicles. My plan so far is a current sensing clamp, and an Arduino micro listening for the current draw ...
3
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3answers
530 views

Car battery (lead acid) discharges much, much faster than it charges?

Let's assume a lead acid car battery (12V, 50Ah, 250A output). According to BatteryUniversity article BU-403: The charge time is 12–16 hours and up to 36–48 hours for large stationary batteries. With ...
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1answer
4k views

How to break this ground loop in my car?

Here's the schematic for my car: simulate this circuit – Schematic created using CircuitLab The head unit is referenced to car's chassis. My amplifier and DSP are in the trunk. The DSP has an ...
1
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3answers
264 views

Only getting data when 'rubbing' wires

I'm trying to use cansniffer and candump to read the CAN bus data in my car with a Raspberry Pi and the PiCAN 2 board, but I have run into a weird issue I can't explain. Situation: I've located the ...
0
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1answer
370 views

Reverse Polarity and TVS Diodes Not Working?

This is a follow up to this issue: Damaged TPL7407LA Transistor Array (*Updated With Scope Testing Images*) We are experiencing both reverse polarity and transient voltage spikes in our automotive ...
0
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1answer
306 views

How to calculate voltage ripple in a BLDC filter module?

Hi I need some calculation for my thesis. A found this picture on the internet. My project is almost the same. It's a pi filter for a 3 phase BLDC. The peak current is 60A. It runs from 12V car ...
2
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1answer
1k views

Automotive battery input EMI filtering

I'm reviewing the schematics for an evaluation board, which uses an LC filter on the DC input as shown here: PWR_IN is defined for the evaluation board as being 7-27V. The issue I'm facing, is where ...
5
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2answers
4k views

How does a car with keyless entry know where the key is?

If I hold the car key and touch the handle on the door, the car locks the doors. But if I leave the key inside the car, it won't lock itself. How does the car know where the key is located? What ...
0
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3answers
156 views

High voltage input and low voltage capacitor in series safety

I’m working with a car battery that has a voltage drop when cranking the engine. As a result of this, the stereo restarts even though it was running already. To resolve the issue of stereo rebooting ...
1
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2answers
185 views

Car battery(12v) to 7v 2a (to power fan controller)

I recently installed an amplifier and sub woofer in my car and it is gets up to 40C where I live so my amp gets VERY hot. I want to build a box/amp rack for the amp which will have fans on each side ...
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1answer
110 views

12V LED remains on

I am working on an automotive project where we are using an LED as an indicator for the operation of an engine cooling fan, which is turned on and off automatically by the vehicle's ECM. The module ...
2
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0answers
270 views

FMEDA failure mode distribution data

We are developing an automotive product according to ISO 26262 standard. For FMEDA calculations failure mode and failure mode distribution is required. Some sources to find these are IEC 61709 ...
1
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2answers
685 views

Can I switch two 12v sources with 5 pin relay?

I'm installing a stereo in an RV and would like to maintain default behavior of having the stereo receive power on vehicle accessory power/ignition, but also be controlled by a switch in the RV for ...
0
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1answer
90 views

Simulate Automotive Speedometer Sender

I am working on a project and I have run into a little bit of a problem. I have a speedometer gauge that I am trying to send a signal to on a bench (out of car). The way in wich the it works is ...
0
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2answers
378 views

Automotive signal isolation - alternatives to optocouplers

I'm working on an automotive project, where I'd like to interface various digital signals to an MCU. The signals can either be ON/OFF (e.g. radiator fans) or measurements of pulse frequency, width, ...
0
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1answer
91 views

High Side Driver IC - Application Information

I have a question regarding VN5025AJ-E: High side driver IC. Datasheet link - https://www.st.com/resource/en/datasheet/vn5025aj-e.pdf In the figure you can see the application schematic. In the ...
0
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1answer
81 views

Car 12V Supplied device - Requirements

I am currently designing a device that is intended to be used outside the car and supplied by car 12V socket (also during the drive). The question is: Are there any specific requirements for example ...
2
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2answers
172 views

EV Charging tripping MCB

We have found that our two EVs are tripping the 32A MCBs in our Consumer Unit, but from my basic knowledge the 2*6.6kW chargers on UK 3-phase should only draw about 19A. I've measured the power ...
1
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1answer
257 views

Arduino and car's 12V switch

I'm trying to control my headlights with my Arduino and a LDR. For this I will use the Arduino as a middle man between the lights switch and the actual lights. The switch has three positions OFF / ...
0
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2answers
119 views

Circuit to supply power to USB during car brownout [duplicate]

I have a USB car charger plugged in the accessory port of my car and I also have a simple bluetooth USB to aux adapter plugged into it. As I start the car, the power drops to the accessory port and ...
1
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1answer
528 views

TH3122 KBus transceiver seems blocking its own TX

I'm using an I/K-Bus transceiver IC from Melexis. This is the one which has collision detection and other functions that makes it easy to send and receive data from the bus. The I/K Bus is a common ...

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