Good morning/afternoon/evening everyone. I am finishing off coding and building my prototype for a project I started a few weeks ago. I am bench-testing it now, but will be wiring it into my car in the next week or so, and wanted to prepare protecting my project from all the noise that it may see once installed.
I am fresh to working with micro-controllers, and small electronics in general, so I apologize in advance if I'm too vague about anything specific in this, and also apologize about my lack of detailed knowledge on this topic. I have an ATMega328 ICU on my board, and I'm running 12v power into the board, but regulated down to 5v using a 7805 regulator, with capacitors on each leg of the regulator. I am tapping into the output wiring of the following 0-5 volt sensors/switches, which are each individually ran into the analog inputs of the board: throttle position sensor (TPS), fuel pressure sensor, manifold absolute pressure (MAP) sensor, air-to-fuel ratio (AFR), oil pressure.
Going to one of my digital inputs is a 5v square wave pulse coming from the "tach" output on the PCM, so I can also monitor the RPM of the engine. Based on certain values I have stated in several conditions, ie: If (TPSvoltage > 2.5 & FuelPressurevoltage < 1.0), a digital output on the ICU will trigger a 12v pulse (via an opto-coupler) to an external, aftermarket rev limiter, to bring the engine down to a much lower RPM until the condition is no longer true, for example.
I will be using 22 AWG wire to and from the sensors/switches, as well as for ground and power from the vehicle's battery to the PCB.
Regarding electromagnetic noise, I am totally unfamiliar with where, specifically, I may be seeing it on my project (the wiring running to/from the sensors, within the plastic enclosure that will be housing the PCB and stored in the interior of my car, or what. I tried doing some general research on the topic, to understand where I might be seeing the noise, and what can be done to shield it, but either I'm just not finding a good source that is easy to understand, or maybe there truly just isn't any solid information out there on shielding micro-controllers from noise in vehicles. If anyone is in need of more information to provide assistance with this please let me know and I will provide that ASAP. Any help would be greatly appreciated!!
-Andrew
I am fresh to working with micro-controllers, and small electronics in general, so I apologize in advance if I'm too vague about anything specific in this, and also apologize about my lack of detailed knowledge on this topic. I have an ATMega328 ICU on my board, and I'm running 12v power into the board, but regulated down to 5v using a 7805 regulator, with capacitors on each leg of the regulator. I am tapping into the output wiring of the following 0-5 volt sensors/switches, which are each individually ran into the analog inputs of the board: throttle position sensor (TPS), fuel pressure sensor, manifold absolute pressure (MAP) sensor, air-to-fuel ratio (AFR), oil pressure.
Going to one of my digital inputs is a 5v square wave pulse coming from the "tach" output on the PCM, so I can also monitor the RPM of the engine. Based on certain values I have stated in several conditions, ie: If (TPSvoltage > 2.5 & FuelPressurevoltage < 1.0), a digital output on the ICU will trigger a 12v pulse (via an opto-coupler) to an external, aftermarket rev limiter, to bring the engine down to a much lower RPM until the condition is no longer true, for example.
I will be using 22 AWG wire to and from the sensors/switches, as well as for ground and power from the vehicle's battery to the PCB.
Regarding electromagnetic noise, I am totally unfamiliar with where, specifically, I may be seeing it on my project (the wiring running to/from the sensors, within the plastic enclosure that will be housing the PCB and stored in the interior of my car, or what. I tried doing some general research on the topic, to understand where I might be seeing the noise, and what can be done to shield it, but either I'm just not finding a good source that is easy to understand, or maybe there truly just isn't any solid information out there on shielding micro-controllers from noise in vehicles. If anyone is in need of more information to provide assistance with this please let me know and I will provide that ASAP. Any help would be greatly appreciated!!
-Andrew
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