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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20 views

12v Input LM2596 Step Down Module to USB 5.2V is Slow Charging

I am trying to use this regulator module (LM2596) to regulate my car's 12V power (constant from fuse port), and use the LM2596 output set to 5.2V to charge my phone (LG G6) but get the slow charging ...
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1answer
29 views

Limit in-rush current for DCDC

We are using a Isolated Fixed-Ratio DC-DC Converter from Vicor (http://www.vicorpower.com/documents/datasheets/ds_BCM4414xG0F4440yzz.pdf) that is powered through a 600VDC accumulator. The DCDC powers ...
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1answer
53 views

How to invert one channel of phone output?

I want to connect phone output to a car radio. It has + and - inputs. When I connect left channel to the + input, there is good quality sound, but it's not as loud as CD player. If I invert right ...
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28 views

How does an optimized car battery charging system could be designed?

To start, I saw a scooter electrics. In that implementation, after quite a weak (in my sense) generator it has some shunt linear regulator, that just dissipates overvoltage to heat. Oh god! Weak ...
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1answer
58 views

Help with wiring OEM LED turn signals that has 2 voltage inputs

The term AFS is used in the 2nd diagram to help differentiate between the bulb type turn signals vs the led type. I'm trying to swap my headlights(without-AFS) to a higher trim version(AFS) on my ...
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0answers
6 views

Automotive relay pin numbers [migrated]

I have the following relay. The pins are numbered 1, 2, 3 and 5, rather than the more usual 85, 86, 30 and 87. I would like the following confirmed: 1 = 85 2 = 86 3 = 30 5 = 87 Thanks
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1answer
35 views

Diode direction for Door Pin Trigger

Which direction should the diode, cathode or anode, be facing for a car security alarm wire? Below is a diagram. When the doors are closed, the wires are testing at 10.1 Volts, settings on the ...
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2answers
96 views

Cannot jump-start car directly when I disconnect the dead battery

So I have a car B with a dead battery and a good functioning car A. I remove the dead battery from B and connect the terminal directly to car A's battery terminals. I cannot start car B. I tried to ...
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2answers
70 views

When jumpstarting a car, why do I need to wait a bit for the bad battery to charge a bit?

So I have a car A with dead battery but good everything else and a car B with good battery. What I did was disconnect car A's dead battery, connect car A's terminals directly to car B's battery. When ...
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1answer
63 views

Galvanic Isolation in Automotive Environment

I am using a linear regulator (MIC29302WU) to power a computer mounted inside my car; however, there is significant noise being passed along the ground of the regulator to the main computer. I ...
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1answer
30 views

MCP2561/2562 CANbus voltage?

The datasheet says the MCP2561/MCP2562 is suitable for 12V and 24V systems except that everywhere I look in the datasheet it says VDD needs to be between 4.5 to 5V. How can CANH be greater than VDD or ...
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1answer
98 views

Switch a 12 VDC circuit from a 0.6 volt signal

I need to switch a 12 VDC circuit (automotive ignition coil) with a .6vdc signal from an impulse coil. I am trying to replace the ignitor box for this engine; they are extraordinarily expensive and ...
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2answers
32 views

How to connect a device to ground using negative signal with high impedance

simulate this circuit – Schematic created using CircuitLab I have a device that enables a ground connection when I press a key on a remote control. This negative signal used to control other ...
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4answers
129 views

Motorbike turn-signal blinker starts OFF, I want it start ON

I bought a cheap blinker that claims to be good for LED bulbs (so the frequency is independent of the load.) It is true, but it has a flaw: the lamps go ON only after about a half second from when I ...
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1answer
38 views

Circuit to supply stable 12vdc from an automotive battery to opamp rails

I've created an Automotive IO board that has digital inputs, digital outputs, analog inputs and analog outputs. Onboard I have an automotive grade regulator to convert the dirty 12vdc to a clean 3.3v ...
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1answer
65 views

High current, high frequency IC PWM switching with MOSFETs

I'm designing a circuit for an automotive application (chassis ground) that has a number of MOSFET outputs to drive large LED arrays and smaller motors (application tends to favour non inductive modes,...
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1answer
105 views

What type of crimp terminals are these?

In my vehicle, I have a 27-pin connector with Volkswagen OEM part number 8K0 972 701 (male) / 8K0 972 702 (female). Etched onto it is the TE Connectivity logo and the number 1718872-1. I am looking ...
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0answers
36 views

ADC Measurement on Automotive Circuit with Arm MCU

I'm trying to develop a circuit capable of measuring voltage on 6 different automotive pins at 12V nominal. I'm hoping to use the integrated SAADC in the nRF52832. I've done some research into ...
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2answers
93 views

Post build flashing of configuration data in embedded systems

I need to implement a mechanism by which I should be able to update the configuration data of some of the modules in a post-build fashion. To describe, consider I have the following files: ...
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1answer
89 views

How to remove flickering on car-powered LEDs?

I am powering an array of LED lights via the car alternator (the LEDs are connected to the car battery leads, but only run when the engine is on). The problem with this setup is that the natural ...
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2answers
319 views

What is the lowest voltage a 12V lead-acid battery in a car could be?

I'm trying to design a product that is powered from the 12V rail inside the car. In normal driving (engine running, electronics on etc.), what would be the minimum voltage of a low battery? Reading ...
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3answers
145 views

Why are “devices utilized exclusively in any transportation vehicle” exempted from FCC compliance testing?

I was researching whether do we need to do FCC compliance testing for a device we developed for a client. Curiously, it seems to be in the list of exemptions (passage taken from here): A digital ...
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1answer
51 views

Looking for a connector with only images to go on

I'm trying to find the connector used for my vehicle's accelerator pedal. Are there any strategies for finding connectors like this?
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2answers
365 views

What happens in the secondary winding if there's no spark plug connected?

The circuit below (minus the transformer and SCR) is used to detect the existence of a flame using the concept of flame rectification. Based on the circuit here: Pilot Light Flame Sensor I have ...
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2answers
108 views

Parasitic drain - What type of relay is this?

I am having issues with my car in that my electric window circuit appears to be taking .2A when the car is off. I have access to the wiring diagram for this circuit and there is a relay (T13) before ...
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1answer
219 views

How do I calculate expected output voltage of car audio amplifier with given conditions?

I have a 4-Channel Amplifier rated at 800 Watt RMS per channel @ 2 Ohm load. Channel 3 and 4 are preset to operate a subwoofer speaker while Ch 1 and 2 are set to operate mid-range speakers at ...
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0answers
61 views

Bulk Current Injection on CAN bus

I'm trying to understand how the Bulk current injection would look like on the CANH and CANL lines, to understand the overloading of the ESD protection diode on the CAN lines and capacitors in ...
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1answer
73 views

I want to know how to charge my 48volt battery park

I have built a solar car by myself, but I can't let my battery get fully charged. I use four 12V batteries as a 48V battery, and I use 3 solar panels. Each have 19V, 18V at early morning and dusk, and ...
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0answers
33 views

How this servomotor calibration is supposed to work at electrical level?

Here is the Wiring Diagram: I am trying to understand how this servo motor calibration process (see screenshot of BMW software) is supposed to work at electrical level. In particular: there is 2-pin ...
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3answers
55 views

How to debounce a low pulse switch for automotive lighting

Hoping you guys can give me a hand with some wiring that I can't quite figure out! Background: I'm trying to rewire a set of automotive lights - these are normally controlled by a computer but I'm ...
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2answers
36 views

In a points ignition system, should the condenser(capacitor) be attached to the coil terminal or to the breaker points

Is there any difference in the function of the circuit if the capacitor has a shorter wire path to the coil or to the points?
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2answers
116 views

Why does the MIT Racecar not use the build in ESC?

MIT has build an autonomous RC race car. They put everything on GitHub. I have a similar project and therefor build one of those for my self (Almost the same but without TX1 and Sensors). I am ...
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0answers
55 views

150 A 12 - 16 V DC Short Circuit Protection

I am powering a ROV from a 4S LiPo battery (12.0 V minimum, 16.8 V maximum). The resistance of the battery is 36 mΩ, so that a maximum current of 470 A can flow through a short-circuit. In order to ...
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0answers
30 views

Automotive 12V Analog and Digital input coupling and isolation

There are numerous questions on SE about classical automotive signal adaptation to microcontrollers. The circuit below uses a few common techniques for analog signal interfacing when a ...
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2answers
198 views

Reliability of STM HAL driver For Safety Critical Application

I'm working on a project which must be used in an automotive application and act as a node into the multiplex CAN-BUS network. There are number of I/O that must be actuated and some of them had a ...
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1answer
71 views

Why are automotive connectors and wires so big?

Cars and motorcycles have many electronic sensors which are small. But it seems they are all connected with big connectors and at least 22AWG wires. Why? I would think 30AWG wires and tiny connectors ...
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0answers
30 views

Switching between two connections - adding LEDs to car reversing light circuit

I am doing a DIY project on my car and need some help. I have 2 LED COB on the back of the car, which is to be used for 2 different things: If I put the car into reverse gear, then the LED comes on ...
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0answers
50 views

Cycle time / transmission cycle in short range automotive radar

I am somewhat newbie in the radar field. I am reading SRR20X-datasheet from Continental. I have two question. What are definitions of Cycle time/transmission cycle (second page)? And in the document,...
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1answer
72 views

Operating relay above coil voltage

I want to power some accessories in my car using illuminated switches on the dashboard. These switches will be wired to the dash illumination circuit, which is normally 12V but can drop as low as 6V ...
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1answer
65 views

Override One Lamp in a Four-Lamp Circuit Using Transistor?

simulate this circuit – Schematic created using CircuitLab I have a circuit of 4 light bulbs, with single switch on the positive terminal that will turn all the 4 bulbs at once. EDIT: Light ...
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1answer
63 views

Best way to shift automotive logic to Arduino TTL

My vehicle ignition switch voltage is 9V when the vehicle is not running. It is 6V when button is pressed. I need a way to convert this to TTL Arduino digital logic levels. I thought I could use a ...
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0answers
39 views

Interference on car bluetooth system

I just did some work on my car audio system and am having some problems with interference. I added a bluetooth receiver and wired it directly to my stereo cd player input. The receiver is powered from ...
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2answers
1k views

How to calculate bus load of CAN bus?

I have a few questions regarding CAN bus load Is there any derived equation/formula to calculate the bus load? I need transmit below frames(Assume Standard frame format) at baud rate 500 kbps on the ...
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0answers
47 views

Simple circuit to sense current drop and apply current to a separate circuit? Trouble with backup dashcam triggering from taillight

Sorry I have very little knowledge of EE but I feel like there must be a simple solution to this. I purchased a mirror dashcam with backup camera function. Backup camera is supposed to be triggered ...
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0answers
70 views

Connecting the secondary side of ignition coil to earth

I have an ignition system used for some application. During the testing I found that spark plug is producing EMI due to spark occurrence and high voltage is traveling through the wire. So to ...
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2answers
57 views

Questions on CAN bit stuffing

I am new to the CAN. I have came across bit stuffing which is used to ensure that all receivers nodes are synchronized to transmitter node (After 5 bits of the same polarity, CAN will add a bit ...
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1answer
36 views

Battery free TPMS

I am doing a report about wireless TPMS, and I heard about products where the sensors in the valves do not need batteries at all (operate and transmit the data). Is that correct?? have you encountered ...
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3answers
73 views

Variable Current Draw from motor for torque control [closed]

I am building an electric go-kart. I would like to use regenerative braking. I would like to have a brake pedal that controls the amount of torque (slowing the motor and wheels down) that the back emf ...
1
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1answer
112 views

DIY Aux In connection to car stereo JVC KD-G151

I would like to connect my phone via jack cable (aux in) to my car stereo, which has no aux input (brand: JVC KD-G151). It is a CD player, so i wrote a silent disk to operate the cd player, and tried ...
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2answers
99 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 ...