Nuns on the Run, v2

I'm surprised this game is reprinted. Didn't expect it to be popular enough.

The board is a lot more colorful and the cards more cartoony. There are two rule changes:

• No more line-of-sight. A nun can see the entire room (smaller rooms now)
• +1 to a nun's detection range if you run

The original board is very dark, but it fits the theme. It is supposed to be dark because it is dead of night!

Determining LoS is more tedious, but it leads to higher tension. You can be in the same room but remain out-of-sight. It makes sense because it is dark. Generally only the chapel and garden is big enough for this.

End of Acquire '93 holy grail quest

I managed to sell this after I brought the price down... significantly. Unlike the AH 98 version, I did't feel so heart-pain. It was a mistake to buy this in the first place.

This edition is meant for Acquire game collectors.

Spacemate in Tuya app

Not bad, has electrical usage statistics too.

The product name is WiFiKIT-II-MRSLIM in Tuya IoT platform. Its version is 3.1.69.

add_ele and cur_power fields are not part of Standard Status Set, so they cannot be queried using Get Operation Log API — until you change the device from Standard Instruction mode to DP Instruction mode. These two fields are sent every 5 mins when in use. Other fields are sent on change only.

Now I'm finally able to achieve fan mode for 20 mins using Tap-and-Run scene.

Installing Spacemate WiFi module

I decided to buy the Spacemate WiFi module after all.

It is pretty small and light.

I cut myself when I removed the air-con FCU front case. It is always difficult if you have never done it before.

Starmex MSXY-FP is easy once you know the correct steps:

• Remove the two screws at the front bottom
• Unclip the clip at the bottom center
• The front cover can then be tilted up
• Once the cover is tilted, the four clips at the top can be released easily one by one

The CN105 port is not on the mainboard on MSXY-FP. It is at the IR receiver. I didn't know that and opened the mainboard cover unnecessarily. Short panic when I could not find the connector.

(This was mentioned in the Spacemate WiFi module installation video, but I didn't know what it meant at that time.)

I decided to run the cable out of the case. It should be possible to tape the module to the metal part and keep it hidden by the front cover.

The front cover can still be closed fully.

Air-con WiFi module by Spacemate

I find it tedious to set my Starmex air-con to fan mode for 20 mins after use. It's not that bad if I turn it off at a consistent time, but at any other time, I need to change the Off time, and this takes time — need to hold the left/right keys and watch the time inc/dec by 10 mins every 0.5s. If only the air-con has auto-fan mode, or a smarter Remote Control, or... WiFi.

Starmex does have WiFi, but it is rare and expensive ($200+ per FCU). Will need to use its app too.

A common workaround is to use a WiFi IR RC, but I want something that connects to the FCU directly.

I googled from time to time and this time, I found a third-party option!

There are two models: for Mitsubishi Electric and Daikin air-cons. Each model has two variants, one local Home Assistant only ($79), the other Tuya ($99).

And it is made by a local Singaporean! (No wonder he targets these two air-con models; they are the most popular models locally.)

It costs $109 on Lazada. It must be due to 'Lazada tax'...

$100 for each FCU is quite ex, though.

Repairing the PV28-CW PM sensor

I was able to undertake this repair only very recently, after I acquired three pieces of information.

This Air Monitor is called PV28-CW. Once I knew its name, I was able to gather very limited information about it. Apparently people had been flashing their own firmware to it (with limited success)!

The first thing is how to take it apart. Apparently it is a common technique to hide screws behind the display cover.

Second is that a common failure for PM sensor is that its fan gets dislodged.

Third is that a dislodged fan can be put back! (If you can get to it.)

Peeled off the display cover

First step was to peel off the display cover. It turned out to be pretty simple.

Opened up

I decided not to disconnect the flex cable since it was not needed to do so. No need to stress it.

A closer look

Can see the CO2 sensor, PM sensor and battery. The battery is 3.7V 800 mAh. It seems a bit bloated. Now that I can open up the unit, maybe I can find a replacement for it. I checked the fan was indeed dislodged by poking it with a micro screwdriver through the air vents.

Removed the PM sensor and battery

I tried to open the PM sensor directly, but found it impossible. I needed to remove the battery before I could peel the PM sensor off — both were taped to the PCB board. I checked that the PM sensor was not soldered on first. The CO2 sensor seemed to be soldered on.

Opening the PM sensor

Needed to pry open the top on all four sides. It was not difficult, just need a micro flathead screwdriver.

PM sensor opened!

Opened! Next was to unscrew the fan. I had to use my smallest micro screwdriver.

Fan is dislodged

I could only lift the fan up a bit. Luckily it was enough to fiddle with the fan blade.

Managed to push it in after some tries. It must have dislodged when I dropped the device from the bookshelf.

Reassembled

In working condition once again! (Battery is still flat.)

Replacing other parts

Will I be able to replace the battery and CO2 sensor?

I was not able to find a 1-to-1 replacement battery. It must exist, just need to search more. Higher capacity would be nice (*), but it won't fit in the space — around 5 cm.

(*) 800 mAh lasts around 4.5 hours, needs 4000 mAh (mobile phone battery capacity) to last a full day. It needs to be much more power efficient, a bigger battery won't help — I want battery life in terms of months.

I also could not find an identical CO2 sensor. There are very similar ones, but I don't know if they are drop-in replacement. Good news: a CO2 sensor costs around 40 - 50 yuan (~S$7.50).

The CO2 sensor is soldered on the PCB, it will take more effort to replace it.

At this point, the best scenario is to hope the CO2 sensor is merely blocked/dusty and a cleaning will unblock it. This is possible because a NDIR sensor is supposed to last for 5 to 15 years. I don't see any opening, though.

Interrupt with current events

Trump bet on an internal regime change. He lost the bet. No doubt part of it was bad intelligence and over-optimism on the instablity of the Iran regime.

The Iran regime understood information was power. In Jan, when there were widespread protests, they cut off all Internet access. Even the supposedly decentralized Starlink failed to work — due to GPS spoofing and radio jamming. They were really prepared.

Many people are unhappy with Trump because he started the war and Iran not only retaliated against USA and the Gulf countries, but it also managed to hold the entire world hostage.

Trump stepped on the hornets' nest, but the hornets' nest is always there.

This war needs to be fought sooner or later. Iran has a stranglehold on the Straits of Hormuz. They already fired missiles at oil tankers in the mid-80s. I did not forget.

While it disrupts world economy now, if Iran ever develops nuclear weapons — and they have always been doing it, despite what they claim — then it is over. No one can threaten them again. And this is why they will pursue it.

A high-precision modular sensor module

Modular sensor module

|Humidity|PM|CO2|VOC|HCHO|Cost (yuan)|
|---|---|---|---|---|---|
|Y|-|-|-|-|27.35|
|-|-|-|Y|-|29.31|
|Y|-|-|Y|-|39.11|
|-|-|-|-|Y|66.53|
|-|Y|-|-|-|76.33|
|Y|Y|-|-|-|85.24|
|Y|Y|-|Y|-|116.51|
|Y|Y|-|Y|Y|151.61|
|Y|Y|Y|Y|-|179.24|
|-|Y|Y|Y|Y|218.44|
|Y|Y|Y|Y|Y|247.84|

Temperature and humidity are precise to 0.1 units. Accuracy is +/- 0.5°C and +/- 3%.

The first 3 rows are taken from another seller.

Estimated component prices:

|Component|Cost (yuan)|
|---|---|
|Board|17.55|
|Humidity|9.80|
|VOC|11.76|
|HCHO|48.98|
|PM|58.78|
|CO2|96.23|

VOC is the most useless sensor in a consumer monitor. It does not distinguish between harmless and harmful compounds, and is misled by humidity and alcohol. It can be used relatively — if the reading goes high, you need to find out why.

HCHO is also known as Formaldehyde. It is a big deal in China due to off-gassing from new building and furniture. It is also not super accurate — it can give false positives.

Once again, we see CO2 sensor is expensive.

As you can see, a complete sensor module is already 250 yuan (S$46.77). I don't expect a complete monitor (with display, WiFi and battery) to be less than 750 yuan (S$140.13).

A new Air Monitor

I had a chance to buy it at 204 yuan (S$38), excluding shipping, but I decided to wait one day and it reverted to its usual price of 224 yuan (S$42). Shipping would add another $5 or so. I decided to get it from Lazada at S$49 instead.

I wonder if I should get a new unit at all. My existing units still limp along fine. I only need to monitor CO2 level in two bedrooms. I realize I don't need to monitor PM2.5 in rooms with air purifier, because the air is 'clean' — the readings are 0 most of the time.

(The air is clean, but dust can still settle over time.)

Update: there is a v2 of this Air Quality Monitor. The WiFi version costs 390 yuan (S$73). The hardware seems to be identical, but it presents data in a different way. It has 3 screens in total. It seems to be available in Chinese only for now.

New model

What I find interesting is that it can measure particulate by count. This is supposed to be more meaningful indoors and at low concentrations.

The temperature and humidity accuracy remain unchanged at +/- 1°C and +/- 5%.

A row of air quality monitors

Msr, B2, B3, Study

It is only today that I know this is called PV28-CW. Apparently someone said it has a real CO2 sensor (NDIR) and a decent PM sensor. That's good to know. If only it is more reliable. :lol:

|Unit|Battery|CO2 Sensor|PM Sensor|
|---|---|---|---|
|Msr|N|N|Y|
|B2|N|Y|Y|
|B3|N|N|Y|
|Study|N|Y|N|

All the batteries have died. They shut off once disconnected from USB power.

What's new? The PM Sensor has spoilt on one unit. At first I thought they were all spoilt, but they show non-zero reading once moved out from their room — the rooms are clean due to air purifier running 24/7.

Only one unit is fully functional now, battery aside.

Taken from TaoBao, these are supposedly the sensors used:

NDIR and PM sensors

The PM sensor has a tiny fan to circulate the air. The fan must have spoilt for the Study unit cos when I use a blower to blow air into the air openings, the PM readings go up, and they quickly return to zero once the blower is removed.

Garbage air quality monitor

I bought this Air Quality Monitor to replace my failing ones. tl;dr: it is garbage.

7-in-1 (left) and 8-in-1

It is bigger than I thought. The physical design is nice. The display is not as polished as the 8-in-1 AQ — the fonts and layout look amateurish — but is acceptable. It shows temperature in both Celsius and Fahrenheit at the same time. It has clock on a separate page — with alarm functionality— can show historical readings (by day) in a graph form and a settings page.

The display is always on. It cannot be turned off. The readings also update rather fast, every 1 - 2s.

After I connected it to Tuya Cloud and proceeded to download the data, it was already several pages long (each page has 100 entries) — even though it was on for less than 20 minutes! It is just as chatty as the 8-in-1 AQ, if not more.

Strangely, battery level is not reported.

Its Tuya detail page is also a little strange. The layout, the font used and the colorful backdrop make it look like an engineering student project with no graphical designer involved. There is no history nor settings. The PM 2.5 unit is also mislabeled as "mg/m^3".

I noticed the CO2 field is named "eco2", so I googled what it meant. Bad news, it means "equivalent CO2". CO2 level is extrapolated from TVOC reading. Human breath contains VOC, so VOC can be used as a proxy for CO2, and VOC sensor is cheap.

Upon cursory observation, both CO2 and TVOC readings go up and down together. They also flucuate a lot and the CO2 reading is wildly off compared to my 8-in-1 AQ. In the same enclosed room, the 8-in-1 AQ measured a steadily rising CO2 from 400+ to 1000+ PPM, but the 7-in-1 AQ still remained at 430+ PPM.

If I wasn't convinced that the 8-in-1 AQ measures CO2 before this, I now am! Its product page says:

From Google AI:

• NDIR Infrared Sensor (CO2): delivers high-precision, stable carbon dioxide detection by measuring infrared light absorption
• Laser Particle Sensor: detects particle concentrations (PM1.0, PM2.5, PM10) such as dust, smoke, and pollution by using a laser to scatter particles
• Semiconductor Sensor: identifies total volatile organic compounds (TVOCs) and formaldehyde (HCHO)
• Optical & Distance Sensors: often used to detect ambient light or measure proximity to objects

The last one is to support its auto-brightness and auto-on features.

Based on my current experience, if you want CO2 reading, you must get one with NDIR sensor (at least). Deriving CO2 from TVOC is bullshit.

The 7-in-1 AQ is likely to have three sensors only:

• Temperature/humidity (one unit)
• PM
• VOC

The PM sensor does not seem to be accurate too. It says the room has ~30 ug/m^3, but I have an air purifier running and it should be < 3 ug/m^3.

Only temperature and humidity readings are correct.

It costs $46.50 (before discount) compared to $60 for the 8-in-1 AQ.

8-in-1 AQ is expensive, but a real CO2 sensor (NDIR) is expensive. eCO2 is total garbage.

From Reddit posts, I found a real air quality monitor: Qingping (青萍) Pro 2. It costs S$200. :horror: You can tell it is good because it shows temperature and humidity to one decimal place. All the cheap ones give round numbers only due to lack of accuracy (temperature +/- 1°C, humidity +/- 5%).

Update: I found on TaoBao there are two variants of this monitor. One comes with VOC sensor (228 yuan; S$42.50), the other NDIR sensor (311 yuan; S$57.90). Note the difference in price. But now that I've used it, I won't get this even if it has NDIR sensor. I'll rather get the 8-in-1 AQ — it's more slick.