The Pedestrian Horn

Dutch forum member OlafH dissected the pedestrian horn a bit and posted this picture.


The horn is a bit hard to get to, one has to remove the front bumper to get to it. I tried to analyse it a bit. Here is a summary of the most important components. Prepare to be amazed.

SPC5602: A generic processor, though aimed at the car industry, made by NXP. It’s current id is MPC5602P. It has 64KB data flash, 20KB RAM, 256KB code flash, and a PMW generator. MPC5602P

TPA3111Q1: A 10 Watt D-class (PWM) mono audio amplifier by Texas instruments. No real surprises on this one. TPA3111D1-Q1

UJA1076A: CAN transceiver, a nifty little chip, made by NXP. It can also acts as a power supply and watchdog. UJA1076A

25P16vpa:  16Mbit (2MB) flash memory, made by ST Microelectronics. I bet the sound files are stored here.  Enough for 2 minutes mp3 encoded data or 12 seconds of raw sound files. 25P16vpa

1334A: Stereo DAC. Hell, this horn is CD quality, they didn’t even use the PMW output of the main processor!!!! Also NXP. 1334A

7342: Dual hexfet. Basically an on-off switch, by International Rectifier, now Infineon: 7342

The horn resells for about 180 Euros. It is hooked up to the Electro CANbus, power, and a few more wires. While I haven’t touched it myself yet, I bet the sound selector push-button is wired directly to it.

By the way. Another name for a Pedestrian Horn is Vehicle Sound for Pedestrians or VSP, though this is officially a Nissan name and developed system.

2 comments on “The Pedestrian Horn
  1. stiloboy says:

    Someone has to work out a hack on this so we can all drive around with F1 sounds, Pod racers, Tie Fighter, Knight Rider, Mysterons, crazy frog, imperial March, or just “Electric car… don’t walk in front of me being shouted out”.

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