Balua – Solar do Mimo


This launch was done in collaboration with the social institution Solar do Mimo, aiming to promote the “Our Dream” project, which boils down to a series of fundraising events to help the construction of new facilities for this institution.

This was a very important launch. The images we could obtain with this launch would significantly help the institution to spread the word out and possibly reaching the media and much more people who might be willing to help.

The launch was on March 29 (Saturday) at 14.30.



Who is Solar do Mimo

Solar do Mimo is a temporary Shelter of children at risk, nonprofit, with public utility status. The headquarters are in São Romão and carries activity for fourteen years.

Children and young people deprived of family environment deserve the same as any other children. Victims of errors, acts and omissions of the adults responsible for them. These kids that were affected by parents, family members and/0r society, have difficult, traumatic and negative life trajectories. In this context, it is imperative to put an immediate end to the risk of mistreatment to which the child is exposed, which often goes by the institutionalization of longer or shorter duration.

It is in this context that the Solar Mimo stands, taking as its premise, reduce suffering and improve the quality of life of children/young institutionalized through properly trained human resources and a welcoming physical environment, helping to build the foundations that empower them for the future, reintegrating them in a family able to give the love, safety and satisfaction of their needs.



  1. Test the new UHF beacon;
  2. Test the new payload layout with heavier end;
  3. Obtain good images and video.




  • Payload = 904g
  • Parachute = 70g
  • Filled Balloon = 1000g
  • Total = 1904g


  • SPOT Tracking System
  • Radiometrix HX1 – VHF transmitter hard-tuned to 144.8 MHz
  • UHF beacon hard tuned to 434.480MHz


  • Venus638FLPx GPS module
  • 1 pressure sensor
  • 1 3-axis accelerometer
  • 1 magnetic compass


  • 6x AA Lithium Energizer batteries.


How it works


The main flight computer was a custom PCB with an ATmega328 running the arduino bootloader. Also on-board is a 3.3V voltage regulator and a Radiometrix HX1 (VHF transmitter, hard-tuned to 144.8 MHz which outputs 300mW (draining 120mA at full RF). The flight computer also connects to the Venus638FLPx module and receives data from 2 temperature sensors, a pressure sensor, a magnetometer and a 3-axis accelerometer. All data is stored on an on-board microSD card. All systems are powered by 6x AA Lithium Energizer batteries. A buzzer was also fitted to facilitate locating the payload.  Lastly, a chemical heater was embedded within the payload casing.

As a backup system we have a SPOT satellite GPS Messenger. This equipment is placed in a special casing that allows it to rotate and always face north.

We also have a beacon that gives a beep in UHF every second (a type of beacon used often in animal tracking). This beacon is used by us in conjugation with a yagi antenna to track the balloon when we are close by (it was important in Barcelos).


The ATmega328 running the arduino bootloader is programmed in C language and the main software loop runs on the following instructions:

  • Reads gps data and parses it,
  • Reads sensors and converts data,
  • Sends data through the HX1
  • Stores data to the microSD card.


Estimated Flight Plan




Pictures and Video

Pictures and/or movies can be found in the gallery section here.

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