If you have followed along from the beginning, you should now have a working, launch control system that tells time, provides weather information and can be hooked up to a computer to monitor the status of the system. However, this is just the beginning. In our final few posts we are going to look at some of the changes, updates and improvements that can be made to the system.
The Hardware
Replace the DHT11 and BMP180 Sensors with a Single BME280 Sensor
This single sensor will do the work of the two sensors in the current system. It is also rather small, so it isn’t going to take up a lot of space. Finally, it uses the I2C communications protocol, the same as the BMP180. This frees up the pin used by the DHT11 to be used for something else.
Replace the LCD screen
There are a couple of improvements here. The first would be to use an LCD screen that also uses the I2C communications protocol. The LCD screen in our project uses 6 pins to communicate with the Arduino. Replacing that screen with one that uses I2C would open up all 6 of those pins to be used for other sensors or equipment.
The second option with the LCD screen is to purchase a larger screen. The one in our project is 16 x 2. However, you can purchase LCD screens that are 20 x 4. While slightly larger that our 16 x 2 screen, you can display significantly more data.
Add a MicroSD card
One of the problems with the current setup is that the data is displayed on the Serial Monitor, but there is no method of saving that data. Adding a MicroSD card reader/writer would heelp solve that issue. They use the SPI communication protocol, which uses some of the pins used by our current LCD screen.
Replace Male Header Pins with Female Header Sockets
On both the Nano and the distribution board, we soldered male header pins as connection points. We used the male pins because this is what we had on hand. Looking back, it would probably be better to use female sockets instead. Using the male pins leaves these connection points open to anything that may get into the box area. This may include debris or loose wires falling down. Anything metal could find itself falling on the pins and shorting out the circuit.
Eliminate the Gap Between Rows on Distribution Panel
When we created the distribution panel we left a gap between each row. While this worked fine for individual lines, it meant using larger DuPont block connectors when attaching wires in pairs or groups of four. For example, to use a four wire connection (power, ground and both I2C cables) it took a 7-pin connector block, with three of the seven pins empty. This turned out to be a waste.
Wire Management
This is something that I should have given more thought to. How you run your wiring and the connectors you use can make the project easy or difficult to maintain. I should have put more thought into making the hardware as modular as the software, making it easier to remove and replace hardware or upgrade components.
Replace the Arduino Nano
There are several options available here. Given the space available in the box you could look at using an Arduino Mega2560 board. There is a big difference in the number of pins available. The Mega2560 has 54 digital pins and 16 analog pins, while the Uno/Nano has only 14 digital pins and 6 analog pins. This would offer you more inputs for things like an add-on weather station and more options at the launch pad.
Replacing the Nano with an Arduino Uno really doesn’t offer any hardware improvements over the Nano. However, because of its larger size it is often easier to work with. If you are having trouble with the Nano due to its small size, then switching to the Uno may be a viable option for you.
Another option would be to look at a completely different board such as the ESP32. This board come with WiFi, Blue Tooth and a MicroSD Card Reader/Writer already built in to the board. It also has over 30 I/O pins for you to use. This is a big step-up from the Nano. However, there are some downsides.
The ESP32 uses 3.3-volt logic, and there are a number of sensors that simply won’t work properly unless they have 5-volts. If you decide to try an ESP32 board be sure to think through the sensors and modules you intend to use.
These are just a few of the hardware updates you could perform on this system. Other thoughts include things like a battery charging system, a system to allow various power sources for the launch pad, maybe a wireless relay to the pad, or what about a recorded messages from a real space launch to replace the buzzer.
In our next post we will look at some of the software updates that you might consider for this project.
Rocketry Research Journal 