Introduction: Bicycle Rear Camera Instead of Back Mirror

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This time I'll introduce some useful bicycle gadget-making ideas without concern to solder any circuit components on PCB.

As you can see in the picture above, all the required components are a smartphone, camera module, and USB cables.

This gadget can be called an electronic back mirror utilizing a camera module, smartphone, and OTG camera viewer program.

I saw some bicycle back mirror accessories on the Internet.

When riding a big auto-bike, a back mirror mounted on the handle is quite useful as it can faithfully show the backside view in the mirror.

But if you riding a small electrical bike like mine, a back mirror is completely useless.

As the bicycle handle width is usually half or 1/3 length of the auto-bike, the back mirror shall only show you in the mirror.

You can't see the backside view with any kind of bicycle back mirror accessories.

That's why I'm making this rear camera for a bicycle.

Step 1: Operation Concept

When you look at the picture above, you can immediately understand the bicycle back mirror problem.

When you mount the back mirror on the bicycle handle, it will show only you.

If you mount the back mirror at the side of a handle with some strange and abnormal method, it can show you the backside view.

But looking at the mirror is a little bit difficult and you should turn your head to look at the mirror.

But if you can look backside view on the small screen mounted on the handle, it will be more convenient and safer to ride a bicycle.

By the rear camera attached to the bicycle luggage compartment, you can easily look at the backside view on the smartphone screen.

Step 2: Parts

Of course, the most important part is the camera.

I bought this camera module from a local (Korean) Internet web store for about 35$.

The technical specification of this camera is like below.

  • Sensor: 8MP 1/4” IMX219
  • Resolution: 8MP 3264H x 2448V
  • Data Format: MJPG/YUY2
  • Field of View (FOV)：H=62.2°, V=48.8°
  • IR Sensitivity: Integral IR filter, 650nm IR Filter, visible light only
  • Frame Rate: MJPG 15fps@3264x2448, 30fps@1920x1080; YUY2 30fps@640x480
  • Adjustable Features: Brightness, Contrast, Saturation, Sharpness, Gamma, White balance.
  • Power Supply: USB Powered 5V
  • Working Current: MAX 200mA
  • Operating Temp.: -4°F~167°F (-20°C~+75°C) 
  • Dimension: 31mmx31mm 

As I'm using a camera module for the first time, the technical specification above seems like encrypted text.

Anyway, this module seems quite popular among many DIY users.

Another important part is the USB gender cable that connects the camera module to the smartphone.

Regarding the smartphone, you can use any brand if the phone can support OTG peripherals such as USB token or OTG camera module introduced above.

I'm using my daughter's unused old LG phone for this project.

Step 3: Mounting Camera to the Bicycle

To get the unobstructed and clear backside view, locating the camera module in the proper position is very important.

As you can see in the picture above, I designated three positions on the backside of the bicycle.

Velcro band is used to mount and fix the camera module to the bicycle.

The most desirable position is on the rear end of the luggage bag surface.

But the cable is too short to connect the camera and smartphone when attaching the camera at the rear end position.

As the USB cable from the camera is about 1 meter, I tried to attach the camera module to the red backlight that is located right under the bicycle saddle. (You can see the white Velcro band is attached to the red backlight in the picture above)

But as the red backlight is mounted in a slanted manner, the camera shows only the road surface view.

I can't see any persons or vehicles approaching when the camera is mounted on the red backlight.

Therefore, I'm mounting the camera in the middle and upright (90 degrees) position as can be seen in the picture above.

Step 4: Connecting Camera to the Smart-phone

As shown in the picture above, the camera module is connected to the smartphone by the USB gender cable.

About 1-meter length of USB cable is included in the delivered camera module kit.

To be connected with a smartphone, the camera USB cable end (Type A male connector) should be connected to the USB gender cable. (USB type A female connector to Type C connecter gender)

For fixing the cable to the bicycle body in the middle, I used a cable tie to firmly attach the cable right under the bicycle saddle.

But I can't attach and fix the cable end side connected with the smartphone for safety reasons.

When the smartphone side cable end is attached to the handle, I can't move the bicycle handle freely either as left or right.

High tension is made to the attached cable when turning the handle left or right while I'm riding.

Although the cable connection is ugly to look at, the overall connection should be like that way as the total length of the USB cable is too short.

Step 5: Backside Viewing With Smart-phone

This is an actual photo showing the rear camera in action.

You can see a wide-angle of unobstructed backside view through the smartphone screen.

I'm using the OTG view app which supports the USB OTG camera module.

The smartphone is LG Q8 that is previously used by my daughter but becomes useless now as she got a new one already. 

After installing the app from the Google play store, no specific setting is required as the app is running like a plug-and-play style.

When you push the recording button of the OTG view app, video captured by a camera can be stored as a file.

As an additional benefit of using the rear camera, you can have video footage of your bicycle journey!

Step 6: Video Captured by Rear Camera

This is the OTG view application menu screen and still image of video captured by the app.

When you select the recording button, you can record video from a camera.

When you look at video footage, the originally captured video changed from color to black & white.

There is a video setting change menu is included in the OTG view app.

As overall video on the smartphone screen is not clear under the sunlight, I had changed application settings to less bright and more black&white like mode.

When you look at the video, another bicycle rider is approaching behind.

As I saw his bicycle on the smartphone screen, I signed him to pass by mine using my hand and at the same time, I moved out from his way.

He seems a little bit surprised by my preemptive and very quick concessive action.

The video above shows exactly why I making this gadget.

From now on I don't need to hear honking from other speedy bicycle riders coming from my behind.

Thank you for reading this story......

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