FlightPlan! vs Stoichiometry Pro

This app allows you to visually program a flight plan for the Tello Drone and then upload it to the drone for execution. You can also fly the drone manually with the app if you wish. Real time telemetry from the drone is displayed on the glass cockpit. Tello is a mini drone equipped with a HD camera that is manufactured by Ryze Robotics and includes a flight controller with DJI smarts. We access the Tello API by connecting to the airframe via a WiFi UDP port. Once a connection is in place, the drone is controlled using simple text commands. So before using the app, make sure that your Tello drone is on and the iPhone is connected to the Tello WiFi. You can check this by going to Settings -> WiFi. The first time that you use the app it will request your permission to use Location Services. This is required to allow the app to determine the SSID of the WiFi connection so we know when you are connected to the drone. The app doesn't use location services for anything else. The app has two modes of operation: manual and planning / auto pilot. The app status is shown in the top centre panel. This panel also indicates whether WiFi is connected or not. It may take a few seconds for a change in WiFi status to be displayed.  If you are connected to the Tello and in manual mode, then tapping the take off icon will cause the drone to auto take off and hover. Tapping land will auto land. Only tap emergency stop if necessary as it will immediately stop all four motors and the drone will fall out of the sky! Tapping the plan button toggles the app state between planning mode and manual mode. In planning mode a grid (representing the ground) and yellow arrow (representing the drone), will appear. The arrow direction indicates the front of the drone. In planning mode, you can enter the sequence of commands which will be transmitted to your drone for execution. Start with take off or you will receive a warning message. When you are finished with your flight plan tap land. The arrow will simulate the position of the drone but is not to scale. Tapping the upload icon will send your flight plan to the Tello and execute it. While the plan is being flown, the app will display the glass cockpit. Real time telemetry from the drone is displayed on the glass cockpit. This includes pitch, roll, yaw, velocity (x, y, z), temperature, time of flight (tof), height, battery percentage, motor on time, barometric pressure, and acceleration (x, y, z). A full description of how the app operates is provided at our website (reefwing.com.au). FlightPlan is a refined version of another that I described in an article called "Programming the Tello Drone using Swift." (https://medium.com/@reefwing/programming-the-tello-drone-using-swift-f9122fd4aeb8?). You can refer to this article to understand how the app operates and create your own version.

Stoichiometry Pro targets common stoichiometric tasks: balancing chemical reactions of unlimited number of components, finding molar masses, moles and masses of reactants and products and defining the limiting reagent, based on chemical formulas, stoichiometric coefficients, and any quantitative data provided. The app analyses chemical reaction typed in “Reaction” field, balances it (if possible), finds molar masses and builds table with list of compounds (reagents and products coloured differently), for quantitative data input. All that triggered by pressing the = button. Example 1: How many moles of H3PO4 are needed in order to obtain 2.0 g of NH4NO3, in the reaction: H3PO4 + (NH4)2MoO4 + HNO3 = (NH4)3PO4(MoO3)12 + NH4NO3 + H2O Solution: The first step is balancing chemical reaction and finding molar masses, since moles-mass conversion is needed. Reaction is balanced and all molar masses are calculated automatically by pressing the “=” button. H3PO4 + 12(NH4)2MoO4 + 21HNO3 = (NH4)3PO4(MoO3)12 +21NH4NO3 + 12H2O, The next step is to find the moles of NH4NO3 from the mass (2.0 g), and then convert them to moles of H3PO4 based on 1:21 ratio obtained from the balanced reaction. Stoichiometry application provides data table that comprised of masses and mole rows for data available before reaction initiated and obtained or left after the reaction is accomplished. When calculate button that pointing towards products, ▶▶ is pressed, the final masses and moles are calculated from the initially provided amounts of reactant and products. On the opposite, when the calculate button pointing left,◀◀, is pressed, then initial reactant and product amounts that would be required to achieve the provided final state are calculated. The later is exactly matches our situation, as we need to find the initial amount of H3PO4 from the final, known NH4NO3 mass. So we set the NH4NO3 mass (2.0 g) to the final mass field and press calculate button ◀◀ to automatically fill the table with all masses and moles for all components. Apparently, 1.19 mmoles of H3PO4 are required to get 2.0 g of NH4NO3. Important Points: Either moles or masses can be filled in, but if both are provided and they don’t match, then the moles value will have a preference. For balancing redox reactions please refer to Electrochemistry application.