Using iPhone without iCloud

I found my iPhone has been more sluggish after upgrading to iOS 14. So I factory reset it last week. Here is my experience.

Firstly I had to sign in my Apple ID to use the phone. So Apple assumes all customers can access Internet and its servers are always up. Can I use my iPhone if Apple goes out of business like Nokia did? I can still use my Nokia X2-00 today.

iCloud was enabled in full by default. There was no option to disable iCloud during phone activation. Apple assumes all customers want to use iCloud. However, iCloud does not have E2E encryption for backups, photos, etc.

I turned off iCloud immediately after activation. Then I found I had to sign in separately for AppStore, iMessage, and Facetime. In addition, ApplePay (wallet) and Sign in with Apple, Find my phone, were no longer available. Airpods Pro won't switch sources automatically. My reasoning is that Apple does not care about users who do not use iCloud because they are the minority.

Since iOS 13 I notice a trend of declining software quality. iOS have gained more and more features. But so did the number of bugs. However, Android is still less polished. Maybe one day I will switch back to Android.

2020 Toyota Corolla SE 1-year review

I have been driving a 2020 Corolla SE with premium package for more than a year. Here are my thoughts on it.

Pros,

• The cloth seat materials are of good quality.
• The dashboard and doors have faux leather soft padding.
• The steering wheel is leather wrapped.
• The steering wheel controls are very easy to operate.
  
• The 2.0L NA engine provides enough horsepower for my everyday use.
• The AC controls are intuitive.
• It has a ton of features like blind spot monitoring, adaptive cruise control, lane tracing, lane keep assist, forward collision warning, and crash imminent braking.
• Fuel economy is top of the line among non-hybrid sedans. I often get 30+ mpg.
• The electronic parking brake can engage/disengage when shifted to/from P.
• It has full LED headlights.
  
• There is a compact spare in the trunk.
  

Cons,

• My biggest complaint is the infotainment system.
• It does not support HD Radio, XM, or Android Auto.
  
• The display is sluggish and does not display Chinese characters.
• Rear cross traffic alert is not offered on 2020 models. It is available on 2021 models.
• The SE base model does not have blind spot monitoring, push button start, or keyless entry. You must purchase the premium package for them. But the premium package includes a mostly useless moonroof.
  
• No auto-dimming rear view mirror options. But I installed one myself. I had to tap into the fuse box to get power.
  
• The headlights did not get the best IIHS rating.
• Only the XLE and XSE trims have steering response headlights.
  
• The rear blinkers are incandescent.
  

Test Driving a 2021 Honda Insight EX

I test drove a 2021 Honda Insight EX hybrid sedan last week. Here is what I think of this car.

The good,

• The headlights are fantastic. They got a good rating in IIHS tests.
• Acceleration is smooth. It has 151 hp and 200 lb.ft torque. It can accelerate from 0 to 60 mph in ~8 seconds, much faster than Corolla hybrid.
  
• The climate control has physical knobs and buttons for temperate, fan speed, circulation, and mode.
  
• The factory radio can display Chinese characters and receive HD radio/XM. Both are not available on 2020 Toyota corolla.
  
• The radio display is of high quality. The UI is very smooth and responsive.
• Audio quality is good.
  
• The instrument cluster is half LCD and half analog. The LCD part can be configured to display various info including a compass.
• It is equipped with blind spot monitor and rear cross traffic alert at no additional cost.
• The telescopic steering wheel has quite a bit range of motion.
• The gear selector is intuitive and easy to operate.
• Backup camera has dynamic guidelines and multiple views.
• In addition to keyless entry, the car can lock automatically when you walk away with the key.
• Fuel economy is good. I got 40+ mpg.
  

The bad,

• The small gas engine can get a bit noisy if you keep the car at full throttle for a while.
• The seats are a bit low even at the highest position.
• The seat fabric does not feel as good as Toyota Corolla's.
• The headliner is always beige regardless of the seat color.
  
• Rain sensing wiper is only available in the touring trim.
• The factory radio does not support wireless Carplay/Android Auto. But 2021 Accord EX-L supports.
• MSRP is a bit high. And currently Honda does not have big incentives.
• The rear blinkers are incandescent, not LED.
• It will release the parking brake automatically. But it would not engage the break when shifted to P. Toyota Corolla can do both.
• The speakers generate fake engine noise in sport mode.
• I could not pause audio with steering wheel controls. The salesman said it is not possible.
• The trunk release button is on the driver side door. I think it should be placed beside the gas door release button.
• No spares tier in the trunk. I would like at lease a donut.
• No dedicated buttons for Carplay/Android Auto/Map on the infotainment screen.
• The center console storage bin is small. And the arm rest is too low.
  

Reduce the audio volume on Tecsun PL-330

I found a method that does not require soldering at Baidu tieba. In FM mode, long press the number 7 key, then the display will show a blinking two digit number. Turning the volume knob will change the number and also the speaker loudness. Short press the 7 key to save the value.

===========================================

I have been using my new PL-330 radio everyday. I got annoyed by two things related to its digital volume control,

• It sets the volume to at least 10/30 for alarms, which is too loud for me.
  
• The lowest volume, 1/30, is too loud when I use earphones of low impedance.
  

So I opened the case to see if I can fix it. Immediately I saw a 16 pin chip. It is a CD1622CB, a clone of SONY's CXA1622 power amplifier.

According to CXA1622 datasheet (shown below), pin 14 controls the gain, i.e. the volume. The gain is greatest if pin 14 is connect to GND, and 0 if pin 14 is connected to pin 15.

On the PCB, a capacitor (labeled 1C25) sits between pin 14 and GND. I measured the voltage on pin 14 while I rotated the volume knob. The results matched the datasheet. I also shorted pin 14 and pin 15, the speaker got muted.

So to reduce the speaker volume, I need to raise the voltage on pin 14. This can be achieved by adding a suitable resistor between pin 14 and pin 15. I experimented with 4.7k, 10k, and 22k. I found 10k most suitable. So I soldered it on.

And now I can use a volume of 6/30 with earphones. And alarms are no longer annoying.

UPDATE

I found the volume levels were not granular enough after the resistor mod. So I removed the resistor and soldered an 1 Watt 20 Ohm resistor in series with the speaker.

Tecsun PL-330 Portable Radio Review

Tecsun released their latest PL-330 portable DSP receiver this summer. I acquired a Chinese version last week for $73.

The good,

• It is compact (139 x 85 x 26 mm) and lightweight (~220g).
• The build quality is good.
• I like the completely flat front surface.
  
• It supports AM synchronous detection and single side band demodulation.
• The easy tuning mode (ETM) has been improved to store shortwave results by clock time.
• You can sort the memory by frequency by long pressing the 0 button when powered off.
• It supports direct frequency entry.
• FM reception is very good.
• The power button is at the correct place and large enough.
• Tecsun finally introduced a tuning step button instead of relying on the user to rotation the tuning knob slowly for fine tuning.
• AM band has three bandwidths, 2.5, 3.5, and 9 kHz.
• AM SSB mode has 0.5, 1.2, 2.2, 3.0, 4.0 kHz bandwidths.
• The digital volume control allows different volume for alarms.
• It supports both 70 us and 50 us FM de-emphasis time constants.
  

The not so good,

• No air band support.
  
• I am not a fan of the tuning and volume knobs. I prefer the style on PL-380.
• MW and SW reception is average.
  
• No FM RDS although its DSP chip supports RDS decoding.
• Synchronous detection does not work well.
• The USB port is micro USB, not type C.
• No 6 kHz bandwidth for AM. 9kHz is too wide to be useful.
• Supports only one alarm clock.
• The snooze button is too small to be useful.
• LCD vertical view angle is small (less than ~90 degrees).
  

The bad,

• It uses the BL-5C lithium battery instead of two/three AA batteries. BL-5C holds less charge than two AA batteries. And it is hard to find good quality BL-5C batteries.
  
• An SSB reverse fine tuning bug was reported by Pawel Kita. (I did not verify.)
  
• It is difficult to operate in darkness. The buttons have a very short travel. The nine buttons on the right are too small. And the "5" button does not have a bump.
• It mutes very briefly while tuning like other DSP radios.
  

I also took it apart for some pictures. There is a connector hidden under the LCD. I guess it is for firmware update.

back

front

In conclusion, PL-330 is worth the ~$70 price. I hope Tecsun fix the small bug in the next firmware release. If you want air and NOAA weather bands, I would recommend CC Skywave SSB.

Disable fingerprint scanner when laptop lid is closed

Since Fedora 32, I was able to enable login and sudo with fingerprints in Gnome settings. However, when my laptop is docked and the lid closed, sudo still prompts from my fingerprints. I have to wait for a few seconds for the fingerprint reader to time out before I can input my password.

I would like to change sudo to skip fingerprint authentication when the laptop lid is closed. I came up with two options,

1. Enable the fingerprint reader when I open the lid and disable it when I close the lid.
2. Change PAM config to check for lid status and skip pam_fprintd.so when the lid is closed.

For either options to work, they need to know the lid status. On my ThinkPad X1 7th gen laptop, /proc/acpi/button/lid/LID/state has the lid status. I think the second option is better. But I did not figure out how to tell PAM to skip pam_fprintd.so conditionally. So I implemented the first solution.

On Linux, you can enable/disable an USB device by setting the authorized bit in sysfs.

I also found a acpid program that monitors ACPI events and runs scripts when certain events happen. I installed it and create these two files.

/etc/acpi/events/lid

event=button/lid.*
action=/etc/acpi/actions/lid.sh 

/etc/acpi/actions/lid.sh

#!/usr/bin/sh
 
PATH=/usr/sbin:/usr/bin
 
grep -q close /proc/acpi/button/lid/LID/state
if [ $? = 0 ]; then
    echo 0 > /sys/bus/usb/devices/1-9:1.0/authorized
fi
 
grep -q open /proc/acpi/button/lid/LID/state
if [ $? = 0 ]; then
    echo 1 > /sys/bus/usb/devices/1-9:1.0/authorized
fi
 
exit 0

So every time the lid status changes, acpid will run lid.sh and it will check the lid status and the disable/enable the fingerprint reader. To prevent acpid conflicting with Gnome, I removed all other files in /etc/acpi/events.

On Digital Terrestrial Radio Broadcast

I have been so absorbed in digital radio recently that I bought a clock radio that support HD Radio last week. I also read Wikipedia articles and technical docs on NRSC-5 (the offcial name for HD Radio) and DAB.

NRSC-5 is the digital radio broadcast standard in the US. NRSC-5 was developed by a private company, iBiquity, which gave it a trademark of HD Radio. It was selected by FCC in 2002 for digital radio broadcast. NRSC-5 supports both AM and FM bands. This article will focus on FM.

NRSC-5 has two modes, hybrid and all-digital. In hybrid mode, a station broadcasts analog audio signal plus two rectangular sub-carriers that contain digital audio and data. In all digital mode the full bandwidth is used for digital audio.

Waterfall plot of NRSC-5 hybrid mode

NRSC-5 has many advantages over analog FM,

• NRSC-5 is more robust against multi-path and fading thanks to OFDM. NRSC-5 also supports single frequency network.
  
• NRSC-5 can multiplex several audio streams encoded in modified HE-AAC on the same frequency. The first stream, HD-1, is the main program. While HD-2/3/4 are supplemental programs. NRSC-5 supports up to 4 audio streams in hybrid mode and 7 streams in all digital mode. All NRSC-5 signals I receive are in hybrid mode.
  
• NRSC-5 supports text, images, and emergency alerts in additional to audio. Several stations around broadcast traffic and weather maps to be displayed on vehicle head units.

I think analog FM broadcast will still exist in the next ten years for these reasons,

• Lack of NRSC-5 receivers. HD Radio is a trademark of a private company. A manufacture needs to pay license fees to produce HD Radio branded devices. So there are very few NRSC-5 capable tabletop/portable radios on the market. While many car radio supports NRSC-5, my car does not. In contrast, Europe's DAB is an ETSI open standard and many manufactures produce DAB capable radios.
  
• There is no federal push for NRSC-5 (This is US). About half of FM stations in my city does not use NRSC-5. I read somewhere that radio stations have to pay for NRSC-5. In comparison, EU requires new cars to support DAB starting in 2021. Norway have switched off analog FM.
• Mediocre audio quality. In hybrid mode, the digital data rate is about 100 kbps. A station needs to allocate it among all audio streams. Most stations I receive allocate 48 kbps to HD-1 and 32 kbps to HD-2/3 each. HE-AAC at 48 kbps does not outperform analog audio. In comparison, a DAB station have about 1 Mbps data rate. Each audio stream gets ~100 kbps.
• NRSC-5 signal uses more bandwidth than analog FM. Adjacent stations could interfere. So FCC initially limited the power of digital signal to 1% of the analog signal. Later in 2010 FCC relaxed the limit to 10%. Still the coverage of digital broadcast is less than that of analog.
• The rise of 4G and Internet streaming services. Many people (including me) listen to music/podcasts on their phone during commute.

References

• NRSC-5 receiver for RTL-SDR: https://github.com/theori-io/nrsc5
• HD Radio homepage: https://hdradio.com/
• Wikipedia: https://en.wikipedia.org/wiki/HD_Radio