Pandemic simulation with Duplo for kids

March 31st, 2020 robin Posted in Uncategorized | Comments Off on Pandemic simulation with Duplo for kids

Both adults and children find “Social distancing” difficult to understand… but children most of all find it difficult to understand why they cannot go outside and play with their friends or grandparents… so I did a simulation with Duplos to help them.

I simplified the model significantly – in part because we don’t have enough blocks to simulate accurately, but also because it would take too long to simulate accurately…

  • Once infected, a person can immediately infect others
  • Once infect it takes 3 days of being infected but having no symptoms before being sick with symptoms
  • Once sick with symptoms it takes 3 days in hospital or 6 days out of hospital to recover.
  • Elderly people who are sick with symptoms and do not get to hospital die… this may seem a bit brutal, but it helps illustrate the effects well.

So to start with, I made 5 families

Five families: “Yellow-head”, “Red-head”, “Pigs”, “Short” and “Scarf-wearing”

Some of the people are marked as “Elderly”.

Elderly people marked with some crepe tape

Day 1 – everyone is at home and healthy

An infection is marked by a yellow brick that the person is standing on. Remember – in our model here a person can be infected (and infectious) for 3 days before showing symptoms, and each day is marked by an additional yellow brick.

The first infection (standing on a yellow brick)

When the infected “Red-Head” comes home, they spread the infection to the rest of their family on the first night.

The first night

The next day everyone goes to school and work… the infection spreads to other families…

Day 2 – the infection spreads.

After the second day, everyone goes home and bring the infection home with them… the Pig family is the only family who didn’t get any infection brought home … yet…

Night 2

Over night the infection spreads…

Overnight the infection spreads

On day 3 the infection spreads further to the school.

Day 3

On night 3 every family is now infected, but nobody knows it yet…

Night 3
Night 3 – everyone is infected

Day 4 and we still have everybody moving around as usual, all infected, but nobody showing symptoms… yet…

Day 4 night time

On night 4 as the sickness progresses, we have the first people showing symptoms (3 yellow bricks replaced with one red brick)

The sickness progresses and the first show symptoms

On day 5 there are already 6 people showing symptoms … and the 5-bed hospital is already full!

In the following night the sickness continues and we have a lot of people sick!

Day 6 (I forgot to move the marker…) and there are many sick, many who cannot get into the hospital, and those who are sick stay at home… hardly anybody can work any more… it’s not looking good!

The next night all of those who were sick, could not get to hospital _and_ were elderly died (red block exchanged for a blue one).

From this point on you can play it out until the end where everybody is either recovered (green block) or dead (blue block).

The kids really enjoyed playing this simulation with me and were very methodical about adding and exchanging the blocks to follow the rules of the sickness that we had agreed on at the beginning. We played the game a few times with different movements: social distancing, total lock down, and looked each time how many people died or survived. The children understood the game aspect of it (our 3 year old decided to take papa pig and fly him around in circles above the town for the duration of the sickness so he wouldn’t get infected at all!), and it helped a lot for them to understand that even though they might get sick and better without a problem, it is still helpful for them not to go out and meet with other children to protect our elderly and vulnerable friends and neighbours.

I hope this sequence of pictures helped, and maybe you will play the pandemic game with your children and it will give you an hour of entertainment and possibly help them understand better what is going on in the world right now.


Jinvoo SM-SW101-3 Switch teardown

November 28th, 2019 robin Posted in Home, Home Automation | Comments Off on Jinvoo SM-SW101-3 Switch teardown

Sometimes people want to see what the inside of a device looks like… so do I! 🙂 So I took apart my new Jinvoo SM-SW101-3 and took some pictures:

I was able to flash it to tasmota easily with tuya-convert and connect it to Home Assistant. :yay:

There’s a template for it too so configuration was a breeze and shortly after I was able to integrate it to home assistant and set up some automations to turn on scenes – I’ve only used two of the three buttons so far so I’ve still got one to play with!

As far as I can tell, the button LEDs are linked to the relays; they cannot be lit independently of the relays. I don’t have anything connected to the relays at the moment, so they click (and draw a little power) when the button is pushed.

With tasmota flashed I measured about 0.5W with all switches off and about 1.3W with all relays on.


Stop coil whining on Gosund SP111

November 18th, 2019 robin Posted in Uncategorized | Comments Off on Stop coil whining on Gosund SP111

The Gosund SP111 is a great wireless plug with an ESP8266 controller built in that can switch and measure mains power. It can be flashed OTA with tuya-convert so you don’t even need to do any soldering to get custom firmware such as tasmota on it. The form-factor is also impressive being so small and at about €12/piece the price is hard to beat. The only major downside is that with low/no load it can have that annoying beep / whistle / whining that comes from a badly positioned / not fixed coil (“coil whining”).

Please be careful – you’re dealing with mains electricity here, so unless you know what you are doing and are ok loosing your guarantee for opening and meddling with the insides of a device PLEASE STOP HERE!

The process is the same for both the V1 or V2 SP111, but you can tell if you have a V2 because they are rated to the much higher 3450W.
Unscrew with a phillips screwdriver (PH 0x50 is about the right size)
Pull off the clear plastic cap
Unscrew the board from the plug pins (one screw in each hole) and and remove the purple rubber pad
Unclip the antenna from the board
Carefully pull the board out of the housing. Pull the antenna cable to the little gap on the side as you are doing this so that it does not get jammed between the board and the housing
This is the coil which is whines…
Put a dab of hot-glue on the coil affixing it to the relay (white block in the centre) behind. Be careful that the glue does not stick out further than the coil or it may jam when you are trying to re-insert the board into the housing.

Now re-assemble everything again carefully remembering all the screws, clipping on the antenna again and the purple pad which keeps the antenna connector in place. When you plug it in again you should find that it no longer whines. 🙂

Pro-tip: this method (putting a dab of hot-glue on the coil) is the solution for nearly all whining power supply issues – the only difficulty is getting them open non-destructively and identifying the offending coil.