Designing a better measuring cup

Great design isn’t always about grand things but it is always about the end user.

a 'squeeze to measure' bottle
a 'squeeze to measure' bottle

Consider this design – an integrated measure for chemicals. This commercial sanitizer is used at a ratio of 1oz per 5 gallons. While some containers have devised a measuring cup using the cap, this bottle had an alternate solution – a measured cup built into the bottle, fed from a small filler tube, also integrated into the bottle from the bottom.

To measure 1oz, the user simply opens the cap on the measuring side and squeezes the bottle. The result is internal pressure in the bottle which pushes sanitizer up the tub and into the measure. Then the user pours the pre-measured liquid.

The measuring “cup” has graduations for smaller amount too.

Soda on tap !

perlick_650SS… another chapter in the continuing saga of “soda on tap” …


In our last episode, the protagonist had just given up on the idea having soda in his home pub when he decided to get some sage advice from “the Google”.

“The Google” told our down trodden bar keeper that his woes were well founded but also his situation was self induced. Thankfully, there was science to the rescue. The Google said, “you need pressure at the bottle but not at the tap.

This idea sounded preposterous. The pressure would be the same from start to finish? right? Wrong.

So, the Google pointed me to “the Science Google”. The Science Google said, “CO2 stays in solution with temperature” – translation, “get stuff cold”. Next, the Science Google said, “diameter is area, and small areas are harder to get through than large ones.” Well, yeah. This bar keeper has gotten larger of the years and definitely finds it harder to get through small spaces. Finally, the Science Google said, “hey blockhead, just use 3/16″ line and make it long – say, 15-20 feet”. He went on to say, “or you can just use a flow control tap.”

So, the bar keeper went to the and found a flow control tap. When it arrived, he connected it to about 5 feet of 3/16″ tubing he had laying around, and he attached his custom soda top adapter.

With great trepidation, he adjusted the flow control to zero and then pulled the tap handle. He then adjusted the flow to a gentle run. To his complete surprise and elation, he quickly poured a tasty, effervescent glass of bubbly!


Now our bar keeper is very curious. Could this science be applied to the bar-gun? might it be possible to use a long length of tubing to get the necessary resistance? stay tuned !

DIY soda dispensing bar gun (aka wunderbar)

You’ve likely see a WunderBar or bar gun – a single dispenser for 4 to 12 different beverages. Bartenders use them to dispense many of the mixers they need from water to club soda to cola.

Cornelius brand bar gun and CO2 distributor

Cornelius brand bar gun and CO2 distributor


A typical modern bar gun is connected to a syrup / water / CO2 mixing system. A long time ago, the soda came pre-mixed in 5 gallon stainless “kegs” and the bar gun was just the centralized dispenser.

The DIY home bar can have something similar! In place of 5 gallon kegs, we will use 2 (or 3) liter bottles.

The system consists of a CO2 cylinder and pressure regulator, a distribution manifold, the bar gun, some tubing, and a bit of DIY to create a fitting for soda bottles.

custom brass soda bottle dispenser head

custom brass soda bottle dispenser head


The trick is to create a custom head fitting that lets CO2 into the soda bottle through one tube and forces the soda out through another tube.

The head part consists of a “street tee” fitting with two NPT-to-barb adapters.

To make the unit, a 4″ length of brass tubing is bonded (soldered or using JB Weld) inside one of the NPT adapters. Next, a brass or copper washer is bonded to the threaded neck of the street tee. The unit assembled with Teflon tape so the brass tube runs down the center of the street tee. A hole is drilled into a soda cap just barely large enough for a snug fit when the threaded neck of the street tee is inserted. A neoprene washer is sandwiched between the washer on the street tee and the soda cap. Finally, it is all tightened together with a nut on the inside of the cap, threaded onto the threaded neck of the street tee.

NOTE: If you use 1/8″ NPT hardware you will have plenty of space inside the soda cap. If you use 1/4″ NPT hardware as in this example, things will be tight and sanding or grinding down the NPT nut will be necessary (which is why the nut in the picture looks round with two flat sides).

Someone on the Internet sells plans for $12 this setup. I found all the details by doing an Internet search for “soda bottle mini keg”.

The setup isn’t cheap (the parts for just one soda bottle head fitting is $15US). So, unless you are doing for the experience of building something or you must have all the cool gadgets, I’d just stick to having soda bottles behind your home bar it in you personal Pub Shed.


UPDATE #1: if I were to build these again, I would switch to 1/8″ NPT and find 1/8″ NPT to 1/4″ ID barb fittings. The 1/4″ NPT fittings are fine but getting a 1/4″ NPT fastening nut inside a soda cap requires it to be ground down considerable and for the through-hole to be perfectly centered in the cap. The change to 1/8″ NPT fittings would not change the flow volumes. It would tighten up the tolerance for the copper tube passing through the street tee fitting which would mean it would need to be perfectly centered. For this reason, I would switch to JB Weld rather than soldering the tub into the NPT adapter fitting.

UPDATE #2: It works fine for non-carbonated but not for carbonated sodas. As I suspected, the small channels within a post-mix gun cause nearly all of the carbonation to be forced out of the soda. I tried several CO2 pressures and the best I could achieve is perhaps 25% carbonation in the served glass. This solution is fine for ice tea, water, lemonade, etc but not for carbonated soda. Oddly enough, it would work for liquors by setting the pressure very low. Of course, you’d want to use nitrogen rather than CO2. You might end up with a tiny bit of cross flavor but it would be very small and easy to solve but leaving water on one line and a quick flush between cocktails. Interesting thought: you could use this postmix gun setup and serve any of the cocktails which do not used a carbonated liquid. Or just learn the fancy moves from the movie Cocktail. There are a few suppliers still selling new premix guns. A 5 (or 7) button new premix guns is about $170US.


Echoes of foot steps

paw prints in relief
paw prints in relief

This is what happens when there is a quick warm up and melt off of snow after a long cold spell. The fluffy snow melts quickly, leaving the previously compressed foot prints.

iOS is not as homogeneous as it once was

Just a few years ago, the big complaint of the Android platform was that is was the wild west. Vendors could choose their own screen resolution and pixel density. This made it difficult for mobile app developers (and designers).

Fast forward to 2015 and there are iOS 7 and iOS 8 deployments, iPhone 4, 5, 5S, 5C, 6, 6P, iPad Mini, Mini Retina, iPad, and iPad Retina. If you want to render all of the needed icons and splash screens for your mobile app, it now looks like this …

iphone-size-comparison16px favicon
32px favicon
57px app icon
72px app icon
76px app icon
114px app icon
120px app icon
152px app icon
180px app icon
1536×2008 portrait launch image
768×1004 portrait launch image
1242×2148 portrait launch image
750×1294 portrait launch image
640×1096 portrait launch image
640×920 portrait launch image
320×460 portrait launch image
1024×748 landscape launch image
2208×1182 landscape launch image
2048×1496 landscape launch image

Thankfully, there is still ImageMagick and it’s ability to script the generation of all these different graphics.

Here is the updated script …

@echo off
echo Utility to generate all of the icons and splash screens for iOS.
echo One files needed in the current directory - mask.png
echo which is used to make iOS looking icons.
echo Assumes there is a file called src10241024.png and that the
echo 'important' material is 768x768 and centered with the remainder
echo of the area being solid color.

for %%S in (16 32) do (
	echo making the %%Spx favicon
	convert src10241024.png -gravity Center -crop 512x512+0+0 -scale %%Sx%%S favicon%%S.ico

for %%S in (57 72 76 114 120 152 180) do (
	echo making the %%Spx app icon 
	convert src10241024.png -alpha off -gravity center mask768.png -compose CopyOpacity -composite -gravity center -crop 768x768+0+0 -scale %%Sx%%S -background transparent icon_%%S.png

for %%S in (1536x2008 768x1004 1242x2148 750x1294 640x1096 640x920 320x460) do (
	for /F "tokens=1,2 delims=x" %%A in ("%%S") do (
		echo making the %%Ax%%B portrait launch image
		convert src10241024.png -scale %%Bx%%B -gravity Center -crop %%Ax%%B+0+0 screen-%%Ax%%B.png

for %%S in (1024x748 2208x1182 2048x1496) do (
	for /F "tokens=1,2 delims=x" %%A in ("%%S") do (
		echo making %%Ax%%B landscape launch image
		convert src10241024.png -scale %%Ax%%A -gravity Center -crop %%Ax%%B+0+0 -rotate 90 screen-%%Ax%%Br.png

Eventually, the sour 1024×1024 image should be undated to about 2400×2400

Compare iPhone in camera pano vs stitching app

Rather than give my opinion, I’ll let you decide which of the following two pictures you like better (click on image to see full size; images modified to increase compression to JPEG 75%) …

iPhone 6 plus camera pano
iPhone 6 plus camera pano

AutoStitch App using 10 photos
AutoStitch App using 10 photos