Lenovo Thinkpad X1 Nano Gen 2 Review

The good,

• sturdy build
  
• 16:10 matte screen
• weights less than 1kg
• good Linux support
  

The bad,

• The keyboard area gets warm when charging.
• Key travel is even shorter than X1 carbon.
• Keyboard is fused with the palm rest. It cannot be replaced easily.
  
• The internal SSD is from Union Memory, a little-known company in China.
  
• No USB-A or HDMI ports.
• The only two USB-C ports are on the left side.
• Everything except for SSD is soldered on the system board.
  

Conclusion: It is a good ultra lightweight laptop. But compromises were made for the weight. X1 carbon is a much better choice if you need more ports.

Block Internet access for IoT devices on Mikrotik RouterOS v7

I have some IoT stuff at home. They are connected to the 2.4GHz band access point on a MikroTik hAP AX3 router. I want to block them from the Internet while keeping them on the same bridge so that things like Airplay would still work.

One solution is to gather all the MAC addresses of the devices and then add firewall rules to reject packets from them destined to the WAN interface list. This is tedious because I need to keep adding MAC addresses for new devices.

Another solution is to create a dedicated WiFi access point for IoT devices, bridge the WiFi interface with LAN, and then configure the firewall to reject packets from this WiFi interface.

However, simply adding a firewall rule that rejects packets from the new WiFi internet does not work because it is L3 firewall only sees the bridge. We need to use the bridge level (L2) firewall as shown below.

/interface wifiwave2
add configuration.mode=ap .ssid="put_ssid_here" master-interface=wifi-ap-2g name=wifi-no-internet security.authentication-types=wpa2-psk,wpa3-psk .encryption=ccmp security.passphrase="put_wifi_password_here"

/interface bridge port
add bridge=bridge interface=wifi-no-internet

/interface bridge filter
add action=mark-packet chain=input in-interface=wifi-no-internet new-packet-mark=block-wan

/ip firewall filter

add action=reject chain=forward comment=\
    "reject wan access for packets marked block-wan" out-interface-list=WAN \
    packet-mark=block-wan reject-with=icmp-network-unreachable

/ipv6 firewall filter

add action=reject chain=forward comment=\
    "reject packets marked with block-wan" out-interface-list=WAN \
    packet-mark=block-wan reject-with=icmp-admin-prohibited

The config above still allows packets from WAN to reach the devices. But they won't be able to send any packets back.

Belkin RT3200 wireless router review

The Belkin RT3200 is a very cheap ($50 on Walmart) WiFi 6 router based on MediaTek's MT7915 + MT7622 solution. It is extremely similar to Linksys E8450. (Foxconn owns Linksys and Belkin.)

Hardware highlights (source):
 - CPU: MT7622BV (2x ARM Cortex-A53 @ 1350 MHz)
 - RAM: 512MB DDR3
 - Flash: 128MB SPI-NAND
 - Ethernet: MT7531BE switch with 5 1000Base-T ports
 - WiFi 2.4 GHz: 802.11bgn 4T4R built-in antennas
                 MT7622VB built-in
 - WiFi   5 GHz: 802.11ac/ax 4T4R built-in antennas
                 MT7915AN chip on-board via PCIe
                 MT7975AN front-end

The router's stock firmware was okay but sluggish. I followed this to install OpenWrt. Just be sure to 1) backup the factory bootrom; 2) use UBI images ending in itb.

Then I enabled beam forming and BSS coloring and ran iperf3. It achieved ~450 Mbps in both direction between my wireless laptop with Intel AX201 and a wired NAS. The laptop was about 8 meters away from the router.

I then switched the bandwidth from 80MHz to 160MHz. But iperf3 did not show improvements. So I reverted the change.

I also connected EA7500 to RT3200. They negotiated a PHY rate of 1733 Mbps. But the iperf3 test was only ~480 Mbps.

I did not enable WED or HW offloading as I configured the router to be an access point.

Conclusion

If you have a decent 802.11ac wave 2 router, replacing it with RT3200 will not increase the throughput much. But it is a good cheap router if you do not have one yet.

MikroTik hAP ax3 WiFi router review

Update in Feb 2025: The latest firmware v7.17.2 still has WiFi issues.

Update in Dec 2023: The router experienced IPv6 connectivity issues. Rebooting would fix for a few hours. I did not find useful logs. I had to backup, reset, restore.

Update in Nov 2023: Mikrotik added station-bridge mode support in v7.12 wifiwave2 package. And the 11ax compatibility issue seems gone.

Update: I do not recommend hAP ax3 until MikroTik fixes the 11ax compatibility issue.

I bought MikroTik hAP ax³ router last week. Here is my review.

the good

• It has a 2.5GbE port.
• It supports WiFi 6 on both bands. Many cheap wireless routers only support WiFi 4 (802.11n) on 2.4GHz.
  
• It has detachable antennas.
  
• It runs the "RouterOS", which supports OSPF, WireGuard, IPSec, etc.

the so-so

• It only supports 2T2R MIMO and 80MHz bandwidth on the 5GHz band.
  
• I ran iperf3 between an iPad Air 5 and a wired NAS via the hAP ax3 and an old Linksys EA7500. I did not notice any increase in throughput on the ax3.
  
• The RouterOS quick setup did not config IPv6. I had to do IPv6 manually.
• The 2.5GbE port defaults to WAN. I changed it to LAN so that the NAS could use it.

the bad

• I encountered several bugs in the RouterOS.
• One of them is this.
• My Linux devices (two laptops and one router) have problem connecting to the 5GHz band AP if it is in 11ax mode. The error is "Unhandled alg: 0xc0400707". I have to set the AP to 11ac mode.
  
• The MikroTik forum does not show attached files (including screenshots) to guests.
• The new wifiwav2 package does not support four address mode or 802.11s. So you cannot deploy a WiFi mesh without tunneling. 
• The wifi interface's MTU cannot be changed.
  

conclusion

hAP ax3 is okay for people who want the RouterOS + 2.5GbE + WiFi 6. You may also consider the $40 cheaper hAP ax2 if you do not need 2.5GbE or external antennas.

 

Eve Energy "Smart" Plug (North American) Review

Update: Eve was acquired by ABB in June 2023.  I am uncertain if eve will keep its privacy commitment.

I bought a Eve Energy "Smart" Plug (model #10027863) recently for $40. I bought it to schedule an oil filled radiator to reduce my electricity bill.

Here is my review, going from positive sides to negatives.

The manufacture claims that the plug does need any registration and does not send any usage data to the "cloud". This was why I chose it over cheaper alternatives like TP-Link Kasa.

The device was made in Taiwan with decent quality components. The FCC internal photos show that it contains an Nordic Semi SoC and a PL7211 energy metering IC.

The plug supports Bluetooth and Thread. The manufacture claimed it would support Matter soon. However, the latency on Bluetooth is human noticeable.

A Thread "border router", e.g. Apple HomePod, is required for remote control due to the lack of WiFi.

The plug works with Apple HomeKit exclusively. It requires an iOS device and the home app. However, not all features are available on the iOS home app.

The plug has a energy metering feature. However, the Eve iOS app is required to view the current power and history. In addition, the manufacture did not specify the accuracy of the metering. So the metering feature has little value to me.

The plug also has an independent scheduling feature. This is why I bought it. Initially, I confused it with the HomeKit automation feature. The latter requires a "home hub". Eventually I found the scheduling UI deep in the Eve iOS app.

The plug has an internal clock but no battery backup. So the schedule stops working silently after a power loss (even a few seconds). The fix is to open the Eve app nearby and let the plug sync the time from the phone. This is very annoying. The manufacture could have put a capacitor inside to keep the clock running for a few hours after a power loss.

It does not have a timer feature. For example, I cannot set it to turn off in 2 hours. Maybe the feature was intentionally left out to avoid more confusion?

The manual control button (integrated with the indicator) is too small for everyday use.

Probably due to the metering circuit, the plug generates some amount of heat. When supplying an 1 kW oil radiator, the plug feels warm (at around 40 degC) in a room at 20 degC.

The plug will eagerly trip whenever it senses a tiny overload. This is good for safety. But I doubt if the energy metering IC is calibrated.

Thoughts on EU USB-C mandates

EU and some other countries will mandate USB-C on cellphones, tablets, and even laptops in a couple of years. I am ambivalent towards such mandates.

Firstly, USB-C is a physical connector specification. It does not guarantee charging interoperability. I encountered several devices with USB-C connectors but only charge with USB-A power adapters. However, I expect that manufactures will learn to implement USB-C correctly eventually.

Secondly, the mandates seem to target Apple only because other phone manufactures have converged USB-C. Apple debuted the reversible lightning connector in 2012. Two years before USB-C came into being. However, Apple holds patents on the connector and tightly controls who may use it. Apple even embeds a small chip into the connector so that phones can refuse to work with unauthorized cables. As a result, lightning connector accessories are more expensive than USB-C counterparts. It seems that complaints to Apple's money grab caught attention from EU legislators and they passed a law to essentially "ban" the lightning connector. However, I don't think such a ban is necessary to force Apple to embrace USB-C. Apple already use USB-C on iPads, probably due to lightning's speed and current limitations. I expect Apple to encounter the same problems on iPhones and thus switch to USB-C voluntarily. In addition, Apple's main patent on lightning will expire in 2032.

Thirdly, I don't think governments should regulate low voltage charging ports. However, governments are justified to mandate certain mains sockets and fuel pumps because they could cause safety issues.

The biggest concern I have on USB-C mandates is the suppression on innovations. Mandating USB-C would disincentive innovators to work on better technologies. The EU lawmakers seem to be aware of this problem. Since the mandate 1)  applies to devices with physical charging ports only and 2) allows manufactures to include other ports in addition to USB-C.

Fitbit Inspire 3 Review

I have been wearing a fitbit inspire 3 fitness tracker for two weeks. Here is my review.

The good,

• Long battery life. I only need to charge it once per week.
  
• Heart rate and sleep monitoring is among the best in the $50-$100 price range.
• It also has a SpO2 sensor.
  

The bad,

• The silicone band is uncomfortable. Probably because my wrist is too thin.
  
• No GPS tracking. But I don't mind.
  
• Does not support wireless charging. 
• I need to manually sync the tracker with my phone due to iOS's restrictions on background syncs. (Edit: background syncs can be enabled on iOS.)
  
• The iOS app is subpar. e.g. I need to go through multiple clinks to see my sleep patterns.
  

The ugly,

• The charging cable is USB-A and less than 1 ft in length.
• There aren't many third party bands for it at the moment.
  
• The Fitbit branded stainless steel band is too expensive ($40).
• Requires a $10/month subscription for "premium" features.
  

 

Eventually I sold the fitbit because I just don't like wearing a fitness tracker everyday.