Hi,
I have a couple of front car cams, which were cheap, but record good quality videos on an sd card.
They can be viewed on a phone via Bluetooth.
The wifi doesn't have a long range, and I would like to either extend the Bluetooth range or tap off composite video, so I could tx it via radio.
Does anyone have any experience with this please?
C

 

OK, now I see that the TS is describing CAMERAS, not "CAMS", as on CAMSHAFTS, used in most engines. (some of us do not understand slang usage of shortened words.)

IF the camera PCB has any sort of video oputput connection, there is a chance of connecting an external display.

 

OK, now I see that the TS is describing CAMERAS, not "CAMS", as on CAMSHAFTS, used in most engines. (some of us do not understand slang usage of shortened words.)

IF the camera PCB has any sort of video oputput connection, there is a chance of connecting an external display.

Hi Mr B,
I did post a photo of the circuit board, and explanation!
It's true sometimes the differences in country slang can be confusing, I'm English and have to look up Americanisms.

I did a fair bit of research, and ended up, extending the antenna (not aerial) as the best solution.
C

 

That probably would have been my suggestion, IF the connection were available. There are probable issues with "lengthening an antenna", if the original one had been matched by setting the length.
Some applications utilize a resonant antenna, and changing the length will change the resonant frequency and often reduce the radiated signal. But other applications may not use a tuned antena and so adding length may work well.
And since We have no information , it is all a guess. Good Luck!!

 

That probably would have been my suggestion, IF the connection were available. There are probable issues with "lengthening an antenna", if the original one had been matched by setting the length.
Some applications utilize a resonant antenna, and changing the length will change the resonant frequency and often reduce the radiated signal. But other applications may not use a tuned antena and so adding length may work well.
And since We have no information , it is all a guess. Good Luck!!

Hi B,
What I hoped for was a HDMI connection, but the main chip didn't have that pin. I looked at reading the SD card writer, but that was complicated, there is a composite pin, but it is hard to connect to, and not the best quality.

When I said lengthening, it was short hand for adding an extension, to different antennas can be tried.
I would like to experiment with filters, but have not found enough time so far.
C

 

An HDMI connector is not at all suitable for any automotive connection because it is not at all sealed, nor vibration resistant. AND it is more expensive than whatever conector that camera package uses.

I do see in the photo that the PCB has a lot of markings for test points and various signals. IF you are able to tell which points are for the antenna, or the composite video signal, you might be able to add a connection. But that is a rather big IF!

 

An HDMI connector is not at all suitable for any automotive connection because it is not at all sealed, nor vibration resistant. AND it is more expensive than whatever conector that camera package uses.

I do see in the photo that the PCB has a lot of markings for test points and various signals. IF you are able to tell which points are for the antenna, or the composite video signal, you might be able to add a connection. But that is a rather big IF!

Hi B,
I only want to use a car camera, because it gives good quality output (SD card), but I don't want to use it in a car,but in a fixed position, sending video to a screen indoors.
The antenna connection is shown here top left (white arrow) and I have added an output from here to outside the camera.
C.

 

OK, my mistake: I assumed that a car camer would be used in a car. In a house is MUCH DIFFERENT, it is Dry, and not shaking. You WILL need to use a coaxial cable for the video connection if it is more than an inch or two. If you are just extending the arial connection, probably finding the mate to that connector in the photo will be a challenge.

 

OK, my mistake: I assumed that a car camer would be used in a car. In a house is MUCH DIFFERENT, it is Dry, and not shaking. You WILL need to use a coaxial cable for the video connection if it is more than an inch or two. If you are just extending the arial connection, probably finding the mate to that connector in the photo will be a challenge.

Hi B,
Car cameras have 2x different qualities, low for the screen and phone monitoring, and high for the SD card, I wanted high, transmitted from a nice view outside, to inside where I could have a large live screen.
What ended up with is a low quality, sent to a phone, that can be used as a security camera.

The antenna connectors are easy to get, I have some.
C

 

If you are saying the bluetooth connection is a low resolution output and is not good enough, then you will have to replace the cameras with something better.

If the bluetooth output is good enough, you could try these bluetooth extenders, which advertise 5km range.
If some nicked your car, you could watch them drive it away and see where they parked it up, if it was 'local'.

https://rfoxia.com/rfoxia-connect-app/

 

If you are saying the bluetooth connection is a low resolution output and is not good enough, then you will have to replace the cameras with something better.

If the bluetooth output is good enough, you could try these bluetooth extenders, which advertise 5km range.
If some nicked your car, you could watch them drive it away and see where they parked it up, if it was 'local'.

https://rfoxia.com/rfoxia-connect-app/

Hi J,
Only what the camera puts on the SD card was the quality I want, and the complication of very fine soldering, then a decoder, put me off, so I put the camera back together, and improved the antenna as mentioned.

As you say I need a better camera to hack.

 

Don't know if this will spark an idea but I once worked inside a steel building inside a steel building. Almost no radio signals got into where my lab was. Someone gave me a spool of 75Ω coax cable, probably close to 100 feet. I ran the cable up through the drop ceiling and out a small vent. Ran that along the top of the inner steel building to the outer skin where there were a number of small holes punched through the skin - for whatever reason. I took about 4 feet of the cable off of the end and reattached it - center lead to the main shielding and the 4 foot shielding was attached to the center lead on the main cable. Then I pushed it out through the hole in the wall. When I checked my radio I could get low end stations but not the high end. So I went back and cut an inch off of the very end of the home made antenna. Kept doing that until I got good signals across the board. I had the only radio in the lab that could pick up radio stations.

I think you said the BT quality was not as high as the recorded video. So this may be a moot point now. But perhaps it's a matter of antenna efficiency. Probably not - but that's all I can offer you on this.

I have an old camera out of a laptop computer. Someday I may actually do something with that. If it runs on 5V I might build it into a model rocket along with a small battery and transmit video back to my phone. Gosh I have a lot of junk laying around I hate to get rid of. Soon as I do I'll want or need it. But I won't need it until it's gone.

 

There are two different things that affect the quality of the video from a camera, aside from the quality of the camera: The frequency response of the connection cable makes a difference, a cable that attenuates frequencies much higher than audio will certainly give a lower quality image. The same with an RF link.

 

Hi,
This car camera, is generally used for backing your story after an accident. It has a low quality screen, and a low quality signal for monitoring it on a phone. Also it has an. In case of an accident, the SD card is taken out and the police can review a high quality video. I was trying to find the connection to the higher quality, but it isn't really practical.

Regarding antennas: Inside the case it a short length of wire attached to the connection shown. I added a balanced coaxial connection to the outside of the case, so I can experiment with different antenna tuning or examples.

For tuning an antenna, a Vector analyser is used, to check the impedance and tuned frequency. I have one. Experimenting like the earlier examples, is interesting, but not the most accurate.
C

 

Not sure what video quality you are getting over WiFi, the Realtek IC is outputting around 13dBm which should give you around 10metres indoors. There are a number of WiFi amplifier modules available (some of dubious quality and approvals) which may help, though, as others have mentioned, that may mess with the antenna matching components.

 

Consider also that the format of the video stored on on the SD card is not the same as what is transitted in the BT wireless format. You get a loss of quality at both ends of te wireless connection.
What sort of receiver for that BT signal are you using??

 

Not sure what video quality you are getting over WiFi, the Realtek IC is outputting around 13dBm which should give you around 10metres indoors. There are a number of WiFi amplifier modules available (some of dubious quality and approvals) which may help, though, as others have mentioned, that may mess with the antenna matching components.

Hi A,
Ok, quality from the YI car cam, with better antenna, now from one end of the house to the other, before it was 5 mtrs.

If it was worth it, I would check the output bandpass, and get a better antenna, but it's not worth it.
C

 

Consider also that the format of the video stored on on the SD card is not the same as what is transitted in the BT wireless format. You get a loss of quality at both ends of te wireless connection.
What sort of receiver for that BT signal are you using??

Hi,
I said that earlier, but the electronic connections and decoder, are too complicated, so not worth it.

As mentioned, the receiver is a phone.
C

 

I see a couple of interesting test points on that second image you posted:

1. C2V8 - just to the right bottom corner of the SD card
2. CVBS - or at least it looks like that - right above the usb (?) connector at the bottom

Either one would lead me to believe that was some kind of composite video output - although the locations seem rather odd placement. But it wouldn't be too difficult to test...

Honestly, there's a lot of neat points to look at - pins for SPI, USB, (oh - and just found a C1V8 test point, on the left side of the board image), two pins for a serial port (that one would be fun to hook up and see what happens on boot)...

Really, this looks like a very "hackable" camera (or at least interesting to poke around on)...

 

I see a couple of interesting test points on that second image you posted:

1. C2V8 - just to the right bottom corner of the SD card
2. CVBS - or at least it looks like that - right above the usb (?) connector at the bottom

Either one would lead me to believe that was some kind of composite video output - although the locations seem rather odd placement. But it wouldn't be too difficult to test...

Honestly, there's a lot of neat points to look at - pins for SPI, USB, (oh - and just found a C1V8 test point, on the left side of the board image), two pins for a serial port (that one would be fun to hook up and see what happens on boot)...

Really, this looks like a very "hackable" camera (or at least interesting to poke around on)...

Hi A,
I think I touched all of the test pads with the input to a composite screen (I don't remember if I proved this was working)but nothing showed.
I asked AI if I could check all of the main chip pin (NT96660) and it said best not to, and offered where it thought I should connect, but as it was under the on screen connector, I didn't.

From what I found, even if I found the Sd card line, it would need a converter between TXing across a distance. (I have the TX and RX, although I'm not sure what quality)

I imagine the serial, would be for phone connecting.

As an interesting project for someone, this is interesting, but it needs too much time for me.
Maybe another time,
Thanks, C.