Monthly Archives: March 2019

Ventilation switch that detects odours

Leave a reply

Many homes in the US have a switch to turn on the ventilation in a toilet or bathroom. Also, all kitchen range hoods and laboratory fume hoods I have seen must be manually switched on and off. Of course the ventilation could be run continuously, but this would be noisy, waste electricity and remove warm air (or cool air-conditioned air in hot weather) from the building. For toilets, bathrooms and kitchens, the main reason to ventilate the room is only temporary – removing odour or humidity.

An untapped business opportunity is to produce a switch that detects odours or humidity and turns on the ventilation just long enough to remove these. Humidity detection is easiest – just connect a hygrometer to the switch. Detecting smelly gases such as grease vapour in the kitchen, hydrogen sulfide, methanethiol and dimethyl sulfide in the toilet may require spectrometry or a chemical reaction. Laboratory gases are probably the most difficult to automatically detect due to their variety.

Parking space availability detection from the air

Leave a reply

Much fuel and time is wasted by drivers zigzagging through a parking lot looking for an empty spot. Some parking garages have automated systems for detecting which spaces are empty and directing drivers to these using electronic displays or coloured lights on the ceiling. Drivers of course prefer to spend less time looking for a space and to find places closer to the exit, so providing availability information gives a commercial parking building a competitive advantage and reduces traffic and pollution inside it. The same availability information would be helpful for outdoor parking lots, including the tops of garages that are open to the sky.

A business opportunity is to develop an app that uses either satellite images or cameras on drones or surrounding structures (highrises or streetlights) to detect empty parking spaces and direct the drivers to these. The cheapest black and white security camera is sufficient to distinguish a car from an empty rectangle of asphalt. Even at the busiest times, such as the peak shopping hours on Saturday afternoon, the parking availability info only needs to be updated about once every 30 seconds to be maximally useful. The only hurdle for this system is the placement of the cameras, because buying two satellite photos per minute for every parking lot may be expensive for the app provider. Drones may not be permitted over urban areas. The owners of the structures surrounding the parking lot may ask for payment to allow camera installation on their property. Of course, permissions should not be a problem if the surrounding buildings are retail establishments who profit from more customers parking closer to them, but the upper floors of tall buildings are typically offices or residential spaces.

Food security is a manipulative term

4 Replies

Food security is a manipulative political code phrase designed to scare people and thereby make them support agricultural subsidies, as I have written before. The fear is created by association with sieges before the age of gunpowder, where castles were starved into submission. In modern times, no enemy is silly enough to try to surround and starve a country that is not a city state (e.g. Singapore), because any enemy with a large enough force to prevent food from getting into a country is also strong enough to conquer it quickly by frontal attack. Even unintentional starvation is a public relations disaster (e.g. Yemen), as is a war that drags on, but a quick takeover without too many casualties (e.g. Crimea) actually increases the conqueror’s leader’s popularity in internal politics.

Even if an enemy was stupid and tried to starve a country, the defense against this is not farm subsidies, but many distributed small stockpiles of food. Farms as a food supply are easy to destroy by firebombing the crops and livestock from the air. A small number of large centralised stockpiles are also vulnerable. However, if each household is obliged to keep n months’ worth of non-perishable food at home, then starving the country into submission would take at least n months and bombardment would not shorten that period.

What is really meant by food security is that food prices might rise. However, in all except the very poorest countries in the world, food is so cheap that any reasonable price rise would not cause starvation. For example, according to the USDA, 9 medium baked potatoes fulfill all the nutritional needs of an adult. Similarly, people can survive for a long time eating just wheat flour and water. Wheat flour is 80 cents per kilo, and a kilo of it has 3600 kcal, which is enough for an adult for two days. The price of flour would have to rise at least a hundred times for the cost to lead to starvation in developed countries. Other emergency foods that do not go bad and can be prepared without heating are also cheap, e.g. milk powder, instant oatmeal, canned meats and vegetables.

A price rise is a financial problem, not not a real resource constraint, and as such has a financial solution – insurance. Those afraid of a price rise can use forward contracts to lock in the price. Insurance against a very low-probability event like food prices rising a hundred times is cheap (if such insurance is offered, which it might not be due to the low demand).

Stockpiling emergency food

2 Replies

Sometimes the media scares people into stockpiling emergency food, such as by predicting a snowstorm (or more poetically, snowpocalypse), flood, hurricane or blockade. Even if the threat of being cut off from food and other supplies was real, so stockpiling would make sense, fear often makes people act irrationally: panicking stockpilers buy the wrong quantities of the wrong products, for example dozens of toilet paper rolls and disinfectant wipe packs.

The smart way to prepare for an emergency is to list the products needed (and only those) and then calculate the necessary quantities. For example, medical handbooks such as UpToDate specify the daily nutrient need for a person conditional on age, weight and physical activity. The quantities of foods that satisfy the nutrient need can be found for example using the USDA food composition database. To find the quantity to buy for emergency preparedness, multiply the total daily food intake of the people in the household by the likely duration of the emergency (plus a reasonable safety margin). Tallying supplies is just like planning event catering or consumables for a hike: the number of eaters times the number of meals. The same simple spreadsheet-based quantity calculation applies to other emergency supplies like matches, batteries, medicine, fuel.

A natural disaster may cause power outages and less frequently a loss of water supply. Therefore emergency food should not need cooking and there should be a drinking water stockpile in the home. Contrary to this common sense, irrational emergency shoppers sometimes buy instant noodles, rice and other foods that require hot water to prepare.

Of course, the stockpile of supplies for a disaster should keep for a long time. A minor and neglected aspect of emergency food is that it should not tempt the stockpiler to eat it at non-emergency times. The temptation of course depends on the person, but chocolate bars may be a bad idea, especially in a household with children or binge eaters.

The requirements of being non-perishable, edible without cooking and non-tempting are satisfied by for example canned food, milk powder, instant oatmeal, flour (despite being usually consumed cooked, flour and oatmeal are edible straight from the pack, in contrast to rice, dry peas, beans and cornmeal).

A minor consideration is variety in the food, which helps keep boredom at bay while waiting for a disaster to end.