I am putting a HVAC controller in my antique 1960 Lincoln. I have an Arduino and control circuit complete. I bought a Pololu D30V30F5 power supply for the Arduino. Can I get some help on designing that with noise filtering and spike protection? I am a beginner.
Your main issue isn’t the Pololu board it’s the dirty 12-volt power in an old car.
A 1960 Lincoln can throw big spikes and noise that reset the Arduino.
You just need a simple front-end: a fuse, a TVS diode, a small inductor, and a couple of caps to give the Pololu a clean input.
Nothing fancy just basic protection so the Arduino stays stable.
I have been designing a circuit for my classic truck. I found no really solid proven and tested circuit on the forum. I was looking for a detailed schematic of something and somebody to say they “have been using this circuit on a classic car with no problems for some years,” and only found “this should work” or “something like this” kind of posts. You can see recently I have been refining it with help from the great folks on the forum and through progress in this thread you can see what circuit I have so far. I have built it and not yet fully tested it.
https://forum.arduino.cc/t/wiper-delay-module-for-classic-car/1407092
The power supply section uses a buck converter like your Pololu one but smaller. Here is what I ended up with for a power supply. As you can see there are 4 components, fuse (5A), 1.5KE18A TVS diode, buck converter, and 100uF 25V capacitor. Power comes in on VIN pin, and powers the ATmega328P using the +5V pin. I also power a couple of 12V relays using the +12V pin.
Your control circuits are not complete until they have similar filtering as as been suggested for your power to the Arduino.
I've got an Arduino Uno in a 1994 Vehicle. The "12V" goes directly into the barrel jack and it's been working fine for a few years. The on-board voltage regulator seems to provide adequate filtering/protection.
I wouldn't be afraid of trying it again in another vehicle. Then if the Arduino were to get fried I'd figure-out a protection circuit and replace it.
Does your Lincoln use a mechanical voltage regulator in the battery charging circuit or a transistorized unit? Mechanical will put lots of spikes on the 12 volt circuit.
Good catch here it is an old style regulator on a generator system.
Thank you for that. I want to try to get this right the first time.
Thank you for sharing that. I want to make this right the first time.
With that car you can see 80V load dump spikes along with a lot of other junk. You also need to protect for reverse polarity. I suggest you start by reading some of the information I have added below to see what you are up against. The automotive electrical system is one of the worst to deal with especially with the older vehicles. There are a lot of parts designed for the automotive environment, I highly recommend you use them in place of commercial parts.
Valuable Resources for Automotive Electronics:
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STMicroelectronics Application Note AN2689:
This application note provides guidelines on protecting automotive electronics from electrical hazards, focusing on design and component selection. Reading this will greatly enhance your understanding of automotive circuit protection.
Read AN2689 -
Analog Devices: Automotive Electronics Design:
This article distills key insights into designing automotive electronics, offering practical advice for engineers.
Read the article -
Diodes Incorporated: Transient Voltage Suppression in Automotive:
Learn about techniques to protect automotive circuits from transient voltage, which is critical for ensuring reliable operation in harsh conditions.
Read the article -
AEC-100 Standards Webinar:
This webinar from Monolithic Power Systems provides a detailed overview of AEC standards, essential for understanding automotive electronics requirements.
Watch the webinar -
Understanding Automotive Electronics, An Engineering Perspective by William B. Ribbens:
This comprehensive book offers an in-depth look into automotive electronics from an engineering perspective, making it an invaluable resource.
Access the book -
Check this for OBD https://vehiclefreak.com/iso9141-code-meaning-how-to-fix/ OBD negotation initialization procedure https://cdn.standards.iteh.ai/samples/16738/20ff360c25c6462b811ebc0c9256eee0/ISO-9141-2-1994.pdf Then there is https://github.com/muki01/OBD2_K-line_Reader PID codes: OBD-II PIDs - Wikipedia
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Load Dump and Cranking Protection for Automotiv Backlight LED Power Suppl https://www.ti.com/lit/an/snva681a/snva681a.pd
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Quality requirements:
http://www.aecouncil.com/AECDocuments.html
https://forum.arduino.cc/t/struggling-with-k-line-iso-9141-2-communication/1307351/9
These resources should provide a strong foundation for anyone involved in automotive electronics design. If you need further help or more resources, feel free to ask!
Holy Cow! How do you have your fingertips on such a library? That is a lot of info! Thank you.
Not his first rodeo!!
I've used these successfully in automotive projects.
https://www.amazon.com/Converter-DROK-Voltage-Regulator-Waterproof/dp/B07P663XJV/ref=sr_1_5
https://www.amazon.com/DROK-Waterproof-Converter-Adjustable-Transformer/dp/B00C0KL1OM/ref=sr_1_6
Yeah, that makes sense. Those old generator/regulator setups are even noisier than modern alternators. I’m not 100% certain, but they can throw some pretty nasty spikes when the regulator contacts open and close, so the Arduino will definitely need protection on the input.
A simple TVS diode + inductor + a couple of caps should help a lot, and the Pololu board will be much happier with that cleaned-up 12V.
That schematic is pretty close to what I had in mind.
When I said “a couple of caps” I was thinking:
one bulk cap on the 12 V side, right at the VIN pin of the buck (after the fuse/TVS),
and one cap on the 5 V side near the Arduino.
In the drawing you posted there’s only one cap (C1) on the 5 V rail.
I’d just add a second electrolytic (say 47–100 µF) from +12 V to GND right next to BUCK1 VIN. That way one cap helps tame the spikes on 12 V, and the other keeps the 5 V rail stiff for the Arduino.
I use this circuit, and you can use it in front of a regulator of almost any sort.
To power most Arduinos I plan on a 9V or 10V supply to the vin pin or barrel, so the onboard regulator doesnt get hot.
The PTC re-settable fuse can be sized appropriately, look for the hold current and trip current in that "RKEF" range to suit your project, like RKEF300 for 3A/6A. Or use a normal fuse.
The TVS can be any of that ...18C range.
The 1uF and 10uF caps can be 50v MKT's or even greencaps, but higher volts is better.
D2 can be any that will carry your full current and not get too hot.
C3 can be as low as 1000uF or as high as needed to handle drop-outs.
L1 is optional, depending on how noisy your supply voltage is. If you leave it out also leave out C1
@wcw858
I have a DIY circuit with an LM7805 regulator on it connected to the 12V on an old pick-up with the mechanical regulator and plain old points ignition.
Been running for 12 years with no problem.
Don't try to concoct some filter using inductors, it can actually make things worse. You really do not need anything complicated, a TVS diode at most.
I see it can get complicated. Thank you Jim. I got the logic proven on a breadboard and moving to the build. Happy Thanksgiving
Unless you live in Flordia you will need that heater.
Happy thanks to you too.