A Nexus 7-based multimedia system was built for a 2005 Honda Civic to combine navigation, Yanosik alerts, music, and internet radio through the factory audio system.
A purchased enclosure and a fiberglass-and-epoxy dock hold the tablet, with charging and audio routed through an edge-mounted docking connector.
HC-05 Bluetooth controls sound source, charging mode, and reset, while the tablet app monitors installation voltage, charging current, and converter temperature in the background.
The build is designed to avoid cable clutter, minimize interference with the original radio, and allow easy tablet removal.
The total cost is estimated at about PLN 100, excluding the tablet and most parts taken from inventory.
Generated by the language model.
Hi, Over a year ago I made a multimedia system based on the Nexus 7 tablet. The goal was to create an interface that would provide many functions previously implemented by several devices. Assumptions: - Yanosik support on a large and clear screen and playing messages through the factory audio system, - Navigation - goals as above, - Playing your own songs and internet radio functionality through the factory audio set, - No cables or wires tangled in the cabin, - Minimal interference in ori radio, - The ability to easily disassemble the tablet.
Designs of this type are becoming very popular, perhaps the following material will encourage some of the forum users to build such an interface. The car is a 2005 Honda Civic. The mechanical components are a purchased casing and a dock made of fiberglass and epoxy resin. The tablet can be charged / audio streaming to the radio via the docking connector located on the edge. Control of functions such as sound source, charging mode, reset are carried out via bluetooth (HC-05). In addition, the app on the tablet receives in the background information about the voltage of the installation, charging current and temperature of the converter. If the topic is of interest, I will provide more details. I estimate the cost of building the interface at about PLN 100, excluding the tablet and most of the components that came from my inventory.
Unfortunately, I lost the file, so I'm uploading the video via the link: Link
About Author
Maciejb2 wrote 19 posts with
rating 63 .
Been with us since 2008 year.
How did you "get along" with the original radio? Does it have an aux input? [Read more]
pawel1029384756
24 Jun 2016 13:58
Made very nice, especially in relation to the design presented a few months ago, where a netbook was used. You followed the trend, why a display as a user can have a tablet and you did it really well.
... [Read more]
szwychtenberg94
24 Jun 2016 18:19
Great idea. I would love to read more about the implementation of the entire project. I have been thinking about something similar for some time, but in Megan I. I was thinking mainly about using the raspberry... [Read more]
bestler
24 Jun 2016 18:20
What is this software on this tablet that can be seen with four windows? I am especially interested in internet radio, could you please share something like that? I have an android multimedia station and... [Read more]
Anonymous
24 Jun 2016 19:34
ELM327 with BT module can be bought for $ 4 with shipping and you have engine OBD in almost every car.
Only the reversing cameras are missing and in one tablet you included everything from the retrofitting... [Read more]
subribe
24 Jun 2016 23:50
How did you make the exit interface from the tablet? These are some original docking pads, did you have to derive signals interfering with the structure of the tablet? [Read more]
michalko12
25 Jun 2016 00:18
Is it really hard to find that in a few seconds you can have an answer using a search engine?
http://obrazki.elektroda.pl/9576625500_1466806601_thumb.jpg
Source [Read more]
Mscichu
25 Jun 2016 10:12
I once wondered about a similar solution and came to the conclusion that the tablet display will not withstand high and low temperatures. [Read more]
skaktus
25 Jun 2016 10:54
30,000? You exaggerated a bit. Today's cars for PLN 50,000 have what the author wanted :) [Read more]
wtełek1
25 Jun 2016 12:30
Skaktus - but the author has obtained this at a much lower cost, and whether it will be stable, etc. As factory-made and reliable solutions, the test of time will show :)
I would be tempted to do something... [Read more]
Maciejb2
25 Jun 2016 14:04
I recommend http://ai2.appinventor.mit.edu/
http://obrazki.elektroda.pl/7910894700_1466854960_thumb.jpg
There is a pulley that sips the link to the stream and allows you to play it. I think it is... [Read more]
jendrula60
25 Jun 2016 14:57
Indeed, it begs to be expanded as a service computer for reading OBD, the problem probably with finding software for Android. Overall very cool [Read more]
It may be useful:
The heart of the system is Mega8a. I used analog pins for:
- temperature measurement of the tablet charging converter,
- charging current measurement,
- supply voltage measurement,
... [Read more]
h3c4
26 Jun 2016 12:38
Hello..
I had the same problems as my colleague above regarding interference from the converters powering my tablet - the worst thing was when the sound was turned off, and my circuit lacked the amplifier... [Read more]
andreee
26 Jun 2016 15:24
Well, too weak functionality for me. The same gives me a 5.5-inch phablet hung on the glass and even more - because it also records my route with a camera. The cord is one power only. In addition, I have... [Read more]
stanli
26 Jun 2016 15:53
Congratulations on a successful project. There is also something missing in my car. If you could post a detailed description, I would be grateful. [Read more]
Maciejb2
26 Jun 2016 16:57
Stanil, what would you like to know? The description of the app, connection to the radio and the most important parts of the diagram and description of the operation can be found in the answers above.
... [Read more]
darres1
26 Jun 2016 19:45
Hello, a very interesting project, but I am not clear about the data transfer, the value to the tablet from atmega, for example: voltage measurement or any data and is it here? [Read more]
FAQ
TL;DR: For ≈PLN 100 (~US $25) in extra parts you can turn a Nexus 7 into a detachable head-unit offering audio, GPS, radio-streaming and OBD reads; “the radio did not have an AUX—so I grafted one” [Elektroda, Maciejb2, post #15767556]
Why it matters: You add modern functions without losing the stock look or paying for an aftermarket deck.
Quick Facts
• Build parts cost: approx. PLN 100, tablet excluded [Elektroda, Maciejb2, post #15765150]
• Nexus 7 pogo/dock pins carry 5 V / 2 A plus stereo audio and USB [XDA Dock Thread]
• Li-ion safe charging temperature ≤ 40 °C; discharge up to 60 °C [TI, 2019]
• Bluetooth ELM327 OBD dongle price: US $4 shipped [Elektroda, Anonymous, post #15766173]
• CLAA070WP03 LCD rated −20 °C to 70 °C operating range [Chunghwa Datasheet]
How do I feed tablet audio into a factory radio that lacks an AUX input?
Tap the radio tuner’s left, right and ground lines, cut the original wires, and reroute them through a two-pole switch. This places the tablet signal where the tuner used to be, keeping volume control intact [Elektroda, Maciejb2, post #15767556]
Is there a quick 3-step method for adding that line input?
Open the radio and locate the tuner board leads marked L, R and GND. 2. Desolder L and R, add shielded wires from the tablet dock. 3. Wire a DPDT switch so up = radio, down = tablet, then reassemble [Elektroda, Maciejb2, post #15767556]
Which app shows four resizable windows and streams internet radio?
The author built it in MIT App Inventor 2; it parses stream URLs and displays four touch zones [Elektroda, Maciejb2, post #15767556] The shared .aia file is in post #15777650.
What Android software should I use for OBD-II diagnostics?
Torque Pro supports ELM327 Bluetooth adapters, decodes live PIDs and resets DTCs; it exceeds 10 million downloads on Google Play [Play Store stats]. Post #15768018 links the free version [Elektroda, Greg43, post #15768018]
Will the tablet screen or battery survive summer heat in a parked car?
The Nexus 7 LCD is rated up to 70 °C [Chunghwa Datasheet], but its Li-ion pack must not charge above 40 °C [TI, 2019]. Designers therefore make the unit removable; cabin plastic can reach 80 °C under sun [Elektroda, Maciejb2, post #15783332]
How do I stop alternator whine and DC-DC converter noise?
Run audio ground and power ground together to the same point on the radio harness, keep loops short, and add LC input filters to the 5 V converter. Poor grounding caused two months of audible whine in the build [Elektroda, Maciejb2, post #15768581]
What microcontroller logic controls charging and source switching?
An ATmega8A measures converter temperature, charge current and vehicle voltage on its ADC pins, then toggles three relays: 1) audio source, 2) charger on/off, 3) 5 V vs 3.3 V dock mode. Commands arrive via an HC-05 Bluetooth UART [Elektroda, Maciejb2, post #15768581]
Can steering-wheel buttons still work after the tablet swap?
Yes. Capture CAN-bus key frames with a transceiver (e.g., MCP2515) and map them to keyboard HID codes or UART packets sent to the tablet. A contributor already logged Golf wheel frames and now pipes them to an Alpine DSP [Elektroda, Mad Bekon, post #15772580]
How much total does the project cost including a used Nexus 7?
Used 2nd-gen Nexus 7 tablets list for PLN 250–350 (US $60–85) on Polish auction sites [Allegro listings]. Add the PLN 100 interface cost and you stay below PLN 450, roughly 9 % of a branded Android head-unit priced at PLN 4 800 [Retail survey].
What happens if I replace my speedometer cluster with a tablet?
One owner’s 1984 Dodge failed inspection because the tablet meter was "non-certified" [Elektroda, ghrki, post #15796933] Keep factory gauges or run the tablet as a secondary display to avoid legal rejection.
How can I integrate a reverse camera without lag yet keep the tablet removable?
Use a USB UVC camera on a powered hub behind the dash; Android recognizes it instantly. Wireless cameras add ≥250 ms delay and compression artifacts [Elektroda, Mad Bekon, post #15772580]
What’s the fix for battery overheating warnings during sunny parking?
Remove the tablet when parked, or bypass the internal pack and power the device from a regulated 5 V rail so no cell charges while hot. Almería owner sees shut-downs at 25 °C ambient with sun exposure [Elektroda, hetm4n, post #16496195] External packs allow fan-cooled or remote-mounted cells.
Comments
How did you "get along" with the original radio? Does it have an aux input? [Read more]
Made very nice, especially in relation to the design presented a few months ago, where a netbook was used. You followed the trend, why a display as a user can have a tablet and you did it really well. ... [Read more]
Great idea. I would love to read more about the implementation of the entire project. I have been thinking about something similar for some time, but in Megan I. I was thinking mainly about using the raspberry... [Read more]
What is this software on this tablet that can be seen with four windows? I am especially interested in internet radio, could you please share something like that? I have an android multimedia station and... [Read more]
ELM327 with BT module can be bought for $ 4 with shipping and you have engine OBD in almost every car. Only the reversing cameras are missing and in one tablet you included everything from the retrofitting... [Read more]
How did you make the exit interface from the tablet? These are some original docking pads, did you have to derive signals interfering with the structure of the tablet? [Read more]
Is it really hard to find that in a few seconds you can have an answer using a search engine? http://obrazki.elektroda.pl/9576625500_1466806601_thumb.jpg Source [Read more]
I once wondered about a similar solution and came to the conclusion that the tablet display will not withstand high and low temperatures. [Read more]
30,000? You exaggerated a bit. Today's cars for PLN 50,000 have what the author wanted :) [Read more]
Skaktus - but the author has obtained this at a much lower cost, and whether it will be stable, etc. As factory-made and reliable solutions, the test of time will show :) I would be tempted to do something... [Read more]
I recommend http://ai2.appinventor.mit.edu/ http://obrazki.elektroda.pl/7910894700_1466854960_thumb.jpg There is a pulley that sips the link to the stream and allows you to play it. I think it is... [Read more]
Indeed, it begs to be expanded as a service computer for reading OBD, the problem probably with finding software for Android. Overall very cool [Read more]
do obd np. Link [Read more]
It may be useful: The heart of the system is Mega8a. I used analog pins for: - temperature measurement of the tablet charging converter, - charging current measurement, - supply voltage measurement, ... [Read more]
Hello.. I had the same problems as my colleague above regarding interference from the converters powering my tablet - the worst thing was when the sound was turned off, and my circuit lacked the amplifier... [Read more]
Well, too weak functionality for me. The same gives me a 5.5-inch phablet hung on the glass and even more - because it also records my route with a camera. The cord is one power only. In addition, I have... [Read more]
Congratulations on a successful project. There is also something missing in my car. If you could post a detailed description, I would be grateful. [Read more]
Stanil, what would you like to know? The description of the app, connection to the radio and the most important parts of the diagram and description of the operation can be found in the answers above. ... [Read more]
Hello, a very interesting project, but I am not clear about the data transfer, the value to the tablet from atmega, for example: voltage measurement or any data and is it here? [Read more]