Management summary: the fairground balloon can carry 5g, will carry an LED light with battery, will carry a microprocessor with the entire IoT device.
In the text we will have a look at the possibilities of using the balloons as carriers of IoT devices. We will show you the available options in terms of refills, the balloons themselves, etc…
When it comes to material, the balloons are usually made of latex and foil. Latex balloons are light and cheap but do not last longer than 10 – 12 hours. Foil balloons are more expensive and heavier but they last for several days. A compromise is the use of latex balloons with a plastic gel, which creates a film inside and the balloon can fly 8 – 10 days. For ascents into the stratosphere, special meteorological balloons, made specifically for that purpose, are used.
Table of latex balloon parameters
|Diameter||12 cm||23 cm||27 cm||28 cm||30 cm||35 cm||48 cm||60 cm||90 cm|
|Volume||1 l||7 l||10 l||12 l||15 l||24 l||57 l||114 l||380 l|
|Weight||1,0 g||2,0 g||2,7 g||3,2 g||3,6 g||5,0 g||7 g||24 g||45 g|
|Max load||5 g||7 g||8 g||11 g||19 g||50 g||90 g||335 g|
According to Archimedes’ law, a balloon is lifted when filled with gas lighter than air. In practice, helium is most commonly used because it is safe and easily accessible thanks to its widespread commercial use. It can be purchased in single-use bombs, which can be delivered by PPL within 2 days after ordering online. It is, however, expensive – approx. CZK 3/litre, which makes the launch of balloons with a 90 cm diameter quite pricy. With the use of a special offer on Slevomat, it is possible to achieve a price of approx. CZK 2/litre.
Alternatively, other gases can be used: hydrogen or methane. However, they are explosive and more difficult to get.
|helium||0.178 g/l||1.112 g/l|
|hydrogen||0.089 g/l||1.201 g/l|
|methane||0.657 g/l||0.633 g/l|
Regardless its dimensions, a balloon is classified as an airplane, which also applies to a regular fairground balloon, and its operation is governed by the regulations of the Civil Aviation Authority. Nevertheless, the purpose of the regulations is mainly to limit the unreported operation of free balloons in high concentration or large dimensions, particularly in the vicinity of airports and heliports, so as not to distract airplane pilots, especially when manoeuvring in low altitudes and also to minimise the likelihood of in-flight collision.
It is important to bring attention to the term “payload“, which are, among others, the materials or objects that could cause damage to the airplane. For this reason, the balloon must not contain, for example, metal wires.
The full text of the regulations can be found here: http://lis.rlp.cz/predpisy/predpisy/index.htm
Operations of unmanned balloons are dealt with in part L2, appendix R.
Permit application: http://www.caa.cz/letadla-bez-pilota-na-palube/balony-bez-pilota-na-palube
It is nice that most modern components with low weight, which are suitable for the construction of light IoT device, work with voltage of about 3V and can be powered by button cells or Li-Ion, Li-Pol batteries, which are easily available. Once again, we get into a conflict between capacity and weight.
|Type||Capacity [mAh]||Price [CZK]||Weight [g]|
Today’s possibilities shift the horizons of development to new dimensions and so we suddenly measure weight in milligrams, currents in microamperes and deal with phenomena such as surface tension of water. We have microprocessors lighter than batteries, colour cameras weighing 1 gram and things in general, our fathers never dreamed of. ?
For example a prototype device, which transmitted information every 3 seconds (normal intervals are 60 or 300 seconds) had a reach of 10 km (!) and operated on the CR2032 battery for approx. 70 hours.
For inspiration, I add a few links to interesting related topics:
– Balloon dimensions: https://www.balonky.cz/rozmery-balonku
– Solar balloons: http://www.balonoviny.wz.cz/
– Colour camera weighing 1g: http://www.fpvhobby.com/63-1-gram-nano-camera-480tvl.html
– Flight with a balloon to the stratosphere and back: http://vtm.e15.cz/vzhuru-do-stratosfery-cesky-i-osobne