Browsed by
Category: Technical

Automated Sand drawings

Automated Sand drawings

I’ve seen these kinds of art devices before – but they are big corporate looking things and run thousands of dollars. “The principles behind them can’t be that complex”, I thought. But there are some tricky bits I didn’t think of before – and this guy does a great walkthrough.

Personally, I would likely have shaved off the bottom part of the marble to create a flat spot and put felt there, so you don’t disturb the lower pattern as much. Also, I wonder if a specialized plexiglass would have worked better instead of glass to help hide the noise.

Synthetic Aperture Radar

Synthetic Aperture Radar

Ever wonder how we get amazing, nearly constantly updated satellite maps that can see through clouds and are now even finding hidden cities in heavily forested, unexplored jungles and lost cities under desert sands?

Scott Manley does an absolutely EXCELLENT job describing exactly how synthetic aperture radar (SAR) was developed over time and the principles behind it. By using polarized radar detection, you can even detect how much oil might be stored in tanks. By using subsurface scattering, you can detect features below tree cover and sand.

The part that was most amazing to me is they actually did the original image reconstruction using analog LENS technology.

Absolutely worth a listen.

Snap Dragon – How to Play the Old Christmas Parlor Game

Snap Dragon – How to Play the Old Christmas Parlor Game


Romancing The Past: Christmas Snap-dragon

Snap dragon was a holiday parlor game popular in England from about the 16th century. It’s typically played at gatherings on Christmas Eve by placing heated brandy in a wide, shallow dish with raisins. The lights are turned off and the brandy is set alight. The participants then try to snatch raisins from the fire and eat the lit fruit.

There is even a poem recorded in Robert Chambers’ Book of days (1879) you are supposed to recite while playing:

Take care you don’t take too much,
Be not greedy in your clutch,
Snip! Snap! Dragon!

With his blue and lapping tongue
Many of you will be stung,
Snip! Snap! Dragon!

For he snaps at all that comes
Snatching at his feast of plums,
Snip! Snap! Dragon!

But Old Christmas makes him come,
Though he looks so fee! fa! fum!
Snip! Snap! Dragon!

Don’t ‘ee fear him but be bold –
Out he goes his flames are cold,
Snip! Snap! Dragon!

You can hear the children playing and reciting this poem in the Halloween episode of Poirot:

Doing it yourself

Atlas Obscura attempted to re-create the experience. I used this as my own guide to try this myself. I found it mostly spot-on. Here was my setup:


  • Raisins: Buy good quality ones that aren’t squished. The bigger/beefier they are, the easier they are to grab. The sweeter they are gives them a great taste when mixed with brandy.
  • Brandy (or rum): 50% (100 proof) smooth, sweet brandy/rum. I found Domaine Tariquet 8 year Bas-Armagnac (cask strength) worked really well. It tasted delicious and burned really well. You’ll probably want to buy a 750ml bottle as you’ll use about half of it per play.
  • Salt – throwing in pinches of salt adds sparking effects that really look cool
  • [Advanced gameplay] Almonds: While they do work, I found they did conduct heat more and upped the difficulty because some items were squishy and others hard when grabbing them from the flames.


  1. Get a large, flat, shallow dish – The dish needs to handle being set on fire and getting very hot. Corelle plates seemed to work well. The dish is going to get very hot so you might also want to put a hot pad under the dish so that it doesn’t ruin the table surface you place it on.
  2. Cookie sheet and CLEAR play area – I found that flaming brandy does indeed splash or drip onto the table as you snatched raisins out. Having the dish in a tray keeps from damaging your play surface.
    You are literally playing with fire – so take all precautions. Make sure your table top and whole area is 100% clear of flammables. Someone might freak and fling a flaming raisin across the table/room. It might be worthwhile to have a damp blanket around to smother flames and baking soda. Remember that water will spread an alcohol fire.
  3. Pour the raisins (and almonds) on the plate – Make sure the raisins are mostly unstuck and can be grabbed individually or in a bunch of no more than 2-3.
  4. Pour ½ to ¾ cup of brandy onto the dish with the raisins. The liquid should not cover the raisins completely.
  5. Warm ¼ cup of brandy in a pan until it’s good and hot – but not boiling. Pour it on top the raisins. Heating part of the brandy supposedly volatilizes the alcohol, increases the amount of vapor, and makes it easier to set alight).
  6. Take a nice long lighter and light it up!
  7. Toss in pinches of salt to add sparks and light!

Try number one

In hindsight, I probably used too much brandy. The raisins were almost all completely below the surface of the brandy. The flames were, to be honest, way too high and too hot to do anything with. I tried grabbing a few fruits, but ended up splashing lots of flaming blue liquid around and getting lots of heat since I had to really dive into the flaming liquid.

I was also getting LOTS of yellow flame. Yellow flame is the hottest kind of flame and will burn you.

Try, try again

According to the Atlas Obscura article, you’re shooting for blue flames which are the result of chemiluminescence, not thermal radiation of yellow flames. As the initial yellow flames burned down, the raisins started poking through the surface of the brandy – making them easier to grab. The flame also started dancing back and forth around the dish – making it EXTREMELY fun to try and time a grab when no flames were in a particular area. It also meant the raisins were warm and brandy filled. Delicious!

This was the absolute most fun time to play. However, it was also towards the last few minutes before the flames died out. Over all, from first lighting to end was only a few minutes – so when you light it up – make sure everyone is ready to play right away!

Here’s what it looked like and me grabbing a few raisins.


I agreed with the other articles – this was absolutely a fun game and definitely worth a shot among adults that don’t mind a little danger and adventure. We’re probably too far along in protective parenting to make this a kids game, but teens might give it a go.

The Atlas Obscura article was really good. However, I would add some tips:

  1. Don’t add almonds your first go. Adding almonds makes things harder for two reasons: there are some hard and some squishy items in the dish and makes judging your snatch from the flames harder. Secondly, the almonds do conduct more heat and can be a hotter grab than raisins towards the end of the game. Finally, they can get a burned coating which makes them not as tasty as boozy raisins.
  2. Ensure the tops of the raisins are above the surface of the brandy. Makes them easy to spot and grab because you’re not dipping so deeply into the flaming liquid
  3. 40-50% alcohol Brandy. 50%/100 proof liquid really burned hot at first, but produced a really nice, long game. I wouldn’t go higher than that.
  4. Sweet brandy – Sweeter/smoother brandy made the soaked raisins taste fantastic. Splurging for a sweeter, high quality smooth brandy really paid off.


Copyright free chill/ambient music

Copyright free chill/ambient music

Are you slapping together that next big startup idea pitch reel? Want to become a streamer or Youtube star? At some point, you’re going to need some background music to fill dead spaces, set the tone, etc. But how does one avoid a dreaded DMCA takedown?

While there are lots of online shops that will sell you royalty-free music, I usually find myself running off to find the amazing amounts of free stuff out there – like this.

Hooking 2 modems together without an active phone line

Hooking 2 modems together without an active phone line

Land lines are getting hard to find these days. Almost as hard to find as old modems.

Back when I was a kid, I wanted to play a network game between two computers in my own house. I achieved this by hooking the modems up in a daisy chain. One modem plugged into the phone line like normal. On the ‘out’ port of the modem, I ran another line from it to the IN line of the 2nd modem. I then had the 2nd modem call our home phone number – which caused our phone to ring, the other modem picked up, and they made their normal connection sounds and connected! I could then unplug modem 1 from the phone line and the computers stayed in contact without issue.

At the time, I thought I needed a dialtone generator or line generator. Little did I know, I could have done it with a simple 9 volt battery and the right sized resistor. Skip along to 8:25 to see how to wire them together.

360 VR Spheres

360 VR Spheres

Nova is an “untethered VR motion simulator,” making virtual reality games and training programs feel more real by rotating in any direction. Their 5.9 foot diameter sphere, which has been compared to a “human-sized hamster ball,” weighs about 1,100 lbs and simulate vehicles of all sorts by being able to move 360 degrees in any direction.

These units are too expensive for the home gaming market, the company leases each Nova unit with ongoing maintenance and upgrades, at a cost of $150,000 US Dollars per year. Eight360 is working with defense forces, mining and forestry industries, where vehicles cost millions of dollars, accidents are a very big deal and training needs to encompass tilt angles.