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frankpintosr
Posts: 7
Joined: Fri Jan 22, 2016 7:30 pm
Location: Portland, OR

Re: Carputer Pi 3

Wed Jun 12, 2019 4:46 pm

Hello everyone! I am working on a Raspberry Pi 3 Model B+ Carputer for my car. I am a complete novice and wondering if someone would be kind enough to look at my design and validate for functionality, provide feedback and/or suggestions. I am most curious about the power circuit which comes from the car fuse block, to a voltage regulator and then to some buck modules. I opted to supply power to some components directly from the buck and not the PI. Will that cause any issues? I have listed all my components below, almost everything from Amazon. I would also appreciate any feedback or suggestions! Thank you in advance!
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1467BC90-C913-425B-ACC8-92BA1D3BEC1C.jpeg (137.59 KiB) Viewed 468 times
1. With the buck converters I was trying to provide “clean” power and reduce the load on the Pi. But if there is no benefit then I can remove them. I have several future enhancements so I’m concerned about running out of Pi provided 5.5v and 3.3v pins.
2. I use iPhone so no Android Auto for me. I also want my unit to be self contained.
3. I purchased the USB mic because I could not get the mic jack on my external sound card to work while using my iPhone to make calls. But the Mic was cheap, $7.99, and it worked immediately.
4. I haven’t selected a shutdown method yet. I was thinking of using four 18650 batteries as a type of UPS. Then configure 2 sets of 2 batteries in series and then parallel. This combined with the shutdown method. Which do you find the most reliable method?

Upcoming additions
1. FM radio and HD radio module of some kind (I’m located in the USA so no dab or dab Plus is available)
2. Rotary dials for volume and FM station tuning
3. Ambient light sensor
4. Front and passenger dash cam with DVR
5. Graceful shutdown with UPS capability
6. RP3 performance enhancements (SD CARD and GPU overclocked)

Future Additions
1. I will be attempting adding steering wheel controls for volume, audio source on the Pi (mp3, FM radio, CD player), and change fm radio station
2. ODB2 integration with dashboard display app
3. Vehicle remote start
4. Waze or other good navigation app
5. Audible app
6. Replace factory Bose amplifier with 5 channel amplifier (CH1 and CH2 Front speakers, CH3 and CH4 rear speakers, CH5 for subwoofer)
7. Add DSP module
8. External USB WLAN for internet

Equipment
2004 Chevrolet Tahoe Z71 with Bose and Onstar
Raspberry Pi 3 Module B+
Offical Raspberry PI 7" Touchscreen LCD Display
GeeekPi Raspberry Pi 3 B+ Cooling Fan
Samsung 128GB EVO Plus Class 10 Micro SDXC (MB-MC128GA)
Coolwoo Backup Camera, 175º Wide Angle with 12 LED Night Vision Lights
REDGO Video Audio VHS VCR USB Video Capture Card
HiLetgo DS3231 High Precision RTC
DIYmall 6M GPS Module with EEPROM with Antenna
UGREEN USB Audio Adapter External Stereo Sound Card
LANMU 48CM TF to Micro SD Extension Cable
eBerry USB Microphone
AmazonBasics 4 Port USB 3.0 Hub with 5V/2.5A power adapter
Rii i8X 2.4GHz Mini Wireless Keyboard with Touchpad Mouse Combo
uxcell Power Converter Regulator Waterproof Voltage Convert Transformer
Moeye 12V Car Add-a-circuit Fuse Adapter
eBoot LM2596 DC to DC Buck Converter 3.0-40V to 1.5-35V Power Supply Step Down Module
Yeeco 4X50W Amplifier Board 4-Channel Car Audio Amplifier Digital Amp Borad With Noise Reduction
Thanks, Frank
RPI3B+ Carputer running OpenAuto
2004 Chevrolet Tahoe Z71 w/ Bose & Onstar
Carputer Diagram https://bluewavestudio.io/community/showthread.php?tid=812

jbuehl
Posts: 32
Joined: Fri Jun 08, 2012 2:49 pm
Location: Los Angeles

Re: Carputer Pi 3

Wed Jun 12, 2019 5:46 pm

I don't think the DC-DC converters you have chosen are going to do what you want them to and might cause problems. I have heard that type of converter can have voltage spikes when they start up. The one I am using https://www.amazon.com/dp/B07H6YZ9XS should be able to provide enough power to run all of your stuff. You definitely don't need a separate 3.3v supply for the RTC. Just power it directly from the RPi. As I mentioned in my last post, I don't bother with a graceful shutdown and I haven't had any problems after 3 years of use.

I like the AdaFruit GPS+RTC hat https://www.adafruit.com/product/2324 because it plugs right on top of the RPi and provides handy breakouts for all the RPi pins, which reduces the spaghetti of connections.

godzilla
Posts: 1
Joined: Mon Jun 17, 2019 4:23 am

Re: Carputer Pi 3

Mon Jun 17, 2019 4:37 am

Hi, total noob here. I am looking to get a RPi and use it to lock/unlock my car via a keyfob as well as connect it to an ODB2 reader to display vehicle data. Any particular fob and ODB reader I should get? My foremost problem is wiring the Pi. First, how do I wire it to the car's battery? Second, I imagine I need to wire it to the car's lock/unlock wires as well. I think I can figure out the rest if I get past those hurdles. Maybe.

fernando.melo
Posts: 8
Joined: Tue Jul 10, 2018 6:14 pm

Re: Carputer Pi 3

Wed Aug 14, 2019 5:12 pm

godzilla wrote:
Mon Jun 17, 2019 4:37 am
Hi, total noob here. I am looking to get a RPi and use it to lock/unlock my car via a keyfob as well as connect it to an ODB2 reader to display vehicle data. Any particular fob and ODB reader I should get? My foremost problem is wiring the Pi. First, how do I wire it to the car's battery? Second, I imagine I need to wire it to the car's lock/unlock wires as well. I think I can figure out the rest if I get past those hurdles. Maybe.
Woa, I barely know where to start...
I guess, at first you need to know your car. I mean, you'll need to learn about how do your vehicle works in matter of locking / unlocking doors. In my car it is done by two specific modules, the driver's side module and the passenger's side module. They receive a specific set of CAN messages trough the CAN-BUS and do their job. You will probably have to sniff your CAN data to find these codes out. I'm using Arduino and a MCP2515 CAN-BUS shield to get CAN messages, I had this spare shield for a while, so I used it, you will probably want a Raspberry version or HAT to do the same. On older cars you won't need all this stuff, you just have to re-wire your door lockers to relays and you are good to go...
Now, for the keyfob part, you will have to look for a solution that includes a keyfob and a receiver and this receiver must be communicable with Raspberry (by i2c, serial, UART, USB, or any other).
For the OBD2 part, well, OBD is just a protocol, you will have to dig and find messages that correspond to information you want to display. I'm using some information to tell me which door is open or ajar, the total mileage of my vehicle, instrument status (headlights, wipers, etc). But I'm not gathering all this info by ODB, instead, I collect CAN messages straight to my Arduino and it tells Raspberry via USB Serial. And oh, yeah, I had to write a program to interpret and display this bunch of info, I did in python with Qt.
Then I would say: as a last step you should wire it to your car's battery, because, a car is not a toy and this hobby can be either funny when everything goes fine and also very expensive when you make something wrong.
I don't know how much you know about Electronics, Programming and Cars, but I guess you will need this knowledge to keep going on your project.
Also, for what you want, if it is just open/close your car and show some info, I don't think you need an entire Raspberry for it. Its more complicated and also an overkill. You can achieve that with a single Arduino Uno R3, in my opinion.

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