Modern cars with lots of electronics always have battery drainage even the engine is off. Electronics will go to sleep mode, but it will still consume a little. I have designed many electronic accessories and decided to check if there is any effect on battery life. My test car is the 2017 Mazda MX-5 RF Launch Edition. It has a SmartTOP module installed as well as my front camera kit, ACC controller, and automatic footwell light.
Measuring current accurately is a little tricky because any circuit interruption will wake up all electronics again. Also range from 10A to milliamps. To avoid these issues, a circuit switch is really handy. I found a good option on Amazon. Because I’m often testing new electronics, I found that having this device installed is time-saving.
Now, when the switch is in position “Power on” I can safely attach the multimeter and after 2 minutes switch can be disconnected and a small current will go through the tester.
The proximity of Key Fob seems to have no effect on this test, however when the car was locked, this current drop to about 15mA, which is a very little drain.
This means if the car is unlocked for a long time, it will drain the battery faster.
The previous owner already installed the CarPlay hub and SmartTop module, but no backup camera. Visibility in this car is not great and I think the backup camera is very essential. For the experiment, I ordered from Amazon a low-cost camera with dynamic guiding lines. To install this camera I need to drill just one small hole (8mm) and attached the camera with the provided 3M tape. It is possible to use a special nut for securing, but I lost it during the installation process.
The camera has a small round 4 pin connector, which makes cable routing very easy. Using a 15″ extension cable with the same round connectors I routed the cable to the CMU. I don’t want to use an extra harness just for the camera, so I soldered female terminals to the 2 power wires and 2 for video and inserted them into the 28 pin connector (main car harness). Camera by spec designed for 12V power, CMU unit provides 6V and it is not an issue, because the camera itself needs just 3.3V. Everything works fine with 6V power.
Guiding lines are simulated, the camera has an integrated gyroscope. I don’t think it is very practical but looks cool.
Installed trunk lid liner, which I designed three years ago for the MX-5 ST. Apparently, the RF trunk opening is a little smaller, so I need to trim a little bit to make it fit better for RF. Picture shown ST version with RF.
Next upgrades will be window controller, OLED display. Work in progress.
Recently I got a request through my Request and Wishlist forum page about making a simple dongle for initiating auto-leveling headlights. Why would you need this? According to Mazda Workshop manual:
Perform headlight auto leveling system initialization if any of the following services is performed:
Auto leveling control module/AFS control module replacement
Auto leveling sensor replacement or removal/installation
Any service which changes vehicle height, such as suspension replacement or removal/installation
Technically you can do this with simple wire jumper, as suggested in that manual:
Perform Steps 4 and 5 within 30 s.
1. Empty the vehicle except for the jack and vehicle tools.
2. Adjust the tire pressure to the specification.
3. Move the vehicle to level ground.
4. Switch the ignition ON (engine off or on).
5. Using a jumper wire, connect DLC-2 terminals B and J (ground) three times at 0.5—1.5 s intervals as shown in the figure. (If the terminals are mistakenly connected, vehicle damage or fire could occur. When connecting with the jumper wire, thoroughly verify what terminals are being connected to prevent a miss-connection.)
The initialization is completed if the LED headlight warning light flashes three times every 0.25 s and turns off. Go to the next step.
If the LED headlight warning light flashes at 0.25 s intervals, the procedure may have been performed incorrectly. Repeat the procedure from Step 4.
6. Verify the LED headlight warning light.
To make this process less stressful, I added little electronics for OBDII connector, which produced 3 stable pulses after a single click on the button.
Since the initial release of the Front Camera kit, I have collected feedback from customers and decided to release a second version. Bug fixing and adding new features is an ongoing task and to make it possible to update software on site, a new USB port was added. Now software can be uploaded from a MS Windows computer via USB cable at any time.
All software features and default settings can be enabled or disabled through the same application:
There was some issue with the Smart Mirror feature. Because we can’t get the absolute position of the mirror, we have to rely on moving time during initial setup. This is not a very accurate method, because sometimes motion up is a little slower than moving down. To compensate for these errors, new software has correction coefficients for each direction. These coefficients are now possible to enter using this new application via USB cable.
Another improvement was done to the main harness. To make installation and access to the module easier, the cable has been extended 15″. The front camera cable now has direct connection to the module via 4pin connector.
Notes about using the “Mute” button for activating Front Camera:
If you press “Mute” to activate the front camera and you want to continue listening to the radio, just turn the volume knob a little. It will exit from mute for radio but the front camera will stay on, until you press the Mute button again.
It was reported that using the Mute button will interfere with CMU updating procedure. However inference is minor. After pressing three buttons combination (Music+Mute+Fav), CMU will switch to front camera. After about 5 seconds, CMU will switch to debug mode and will show normal interface again.
My windows switch modification for automatic roll-up windows became a very popular mod among Miata enthusiasts. However, the original modification, for most people, was somewhat difficult due to high precision soldering. To make it more accessible, I designed an external controller with a wire harness, which is now an easy plug-n-play setup.