Poor people in China transport natural gas in large plastic bags. If this could be made safe it’s a very low cost alternative to expensive pipelines. Natural gas could be quickly and cheaply distributed to places without infrastructure.
Running underground pipes is a large investment. The small amount of natural gas these people would use doesn’t make that investment worth while.
The danger is if the gas is ignited. Three things are required to cause this danger, enough oxygen for ignition, natural gas mixed with oxygen, spark or flame.
A very simple solution is to put the natural gas bag inside another bag filled with carbon-dioxide. This would prevent ignition. CO2 could also be used to prevent an explosion while filling the bag with natural gas. First fill the bag with CO2 then use the natural gas to force out the CO2 into another empty bag of the same size. When the second bag is full you know the first bag is filled with natural gas. The process could then be repeated with the second bag.
Ideas to make high precision low cost head positioning systems for 3D printer / fabricators / CNC machines. Precision stepper motors are expensive. What if you could use cheap analog motor? They could be very fast and cheap.
Run a length of wire along each axis of the printer / fabricator / CNC and measure the resistance at the head position. Using a table of actual resistance measurements on the device could increase accuracy and even heat differences could be taken into account. This could be extremely accurate and low cost.
Optical is another approach, this is how mechanical mice and mane printers function. Using a digital camera with distance measurements on a scale printed from a long format printer could make the device very fast and accurate. Using optics the accuracy could increased fine precision even with cheap webcam sensors.
Mounting an RF transmitter on the head and antennas at the corners of the tracks could allow triangulation of the head to extremely high precision even over very large distances. This is the same technique used by GPS and cell phone towers. The precisions scales with size and frequency transmitted.
Using opposing electrical currents to create a balance for any location along the rail. With the correct calibration this can be very accurate plus provide very fast movement.
Aquapod Emergency Water Storage is a low cost way to safely store 65 gallons of clean water, a 14 day supply for a family of four.
Not exactly an overlooked innovation since the plastic technology to make this cheap is fairly new. This does use an existing resource, the bath tub, to provide the strength to store the water which weight 520 lbs (236 kg). Using the bathtub this way allows the Aquapod to be much thinner plastic and thus lower cost. It also uses a space which won’t be used during an emergency. If the water is not running the bath tub won’t be used so storing water there does not take up extra space. Furthermore it uses the readily available supply from the faucet, assuming to have time to prepare for an outage. The kit comes with a hand pump making it perfect for use when power is out.