Low-Cost Research Glove Box Operating Instructions

The purpose of this Instructable is to walk through the operating instructions for the Low-Cost Research Glove Box found at the following link: https://www.instructables.com/id/Low-Cost-Researc...

Materials Needed:

· 1 ECOTech glove box (refer to Build Instructions for details)

· 1 computer with USB port

1. Inspect the ECOTech glove box. All doors should be easy to open and close, all wires configured as shown in the Build Instructions, all wires should be in good condition, etc.

2. Prepare your humidity source in one of the jars provided. This can be pure water or a saturated salt solution.

3. If needed, download the free Arduino software to your computer. It can be found at https://www.arduino.cc/en/Main/Software.

4. If needed, download the free Arduino sensor libraries, DHT.h (https://github.com/adafruit/DHT-sensor-library) and Adafruit_Sensor.h (https://github.com/adafruit/Adafruit_Sensor).

a. Download the ZIP folder from the linked site.

b. Once fully downloaded, open the file location of the downloaded folder. Extract the downloaded folder.

c. Save the WHOLE folder under C:\Documents\Arduino\libraries (if this is your first time using Arduino, you may have to create the libraries folder). If the libraries are saved in the wrong location or the wrong format, the program WILL NOT WORK.

d. Repeat this process with the other library if necessary.

If downloading the digital file:

I. Download the file Glove_Box_Code.ino provided

II. Open the file with Arduino, and Save As in a convenient location for you. (We recommend C:\Documents\Arduino)

If you do not have access to the digital file:

I. Open Arduino.

II. Copy the text from the attached Arduino Code Text into a new .ino file. It is very important that the text is copied EXACTLY. A single typo can prevent the entire code from working. If you have any trouble getting it started for the first time and used this method of obtaining the code, then this is the most likely place that an error has occurred.

III. Save the .ino file in a convenient location for you. (We recommend C:\Documents\Arduino)

1. Open Glove_Box_Code.ino with Arduino. Verify the code (Refer to Figure 2) to ensure that it is still free of errors.

2. Open the valve that is fed to the jar you wish to use in your experiment.

3. Set up any other aspects of your planned experiment. If there are items that need to be inside the main chamber, or wires that must be passed through the hole in the side of the box, set these up before starting the program. While the program is running, opening the main door should be avoided. If needed, items can be passed through the smaller chamber in order to minimize the impact on the environment of the main chamber.

4. Set the user-controlled variables. Detailed explanations of each variable can be found in the next section.

5. Connect the USB cord between the Arduino unit and your computer. Open the Serial Monitor (Refer to Figure 2). Upload the code into the Arduino unit (Refer to Figure 2).

6. After the internal environment of the main chamber has reached the desired conditions, your experiment can be performed.

Humidity

· Name in the ECOTech code: humidity

· Purpose: User inputs this value as the target relative humidity of the main chamber.

· Use: Input the desired relative humidity for your experiment, and open the appropriate valve connecting the air pump to the humidity source. When uploaded, the program will read the humidity and temperature every five seconds. If the actual humidity is outside of the defined range, the air pump will blow humidified air into the main chamber. When the target humidity has been reached, the air pump will shut off.

· NOTES:

o This value is the target relative humidity, not a reading of the actual current humidity, and not an absolute humidity value. As such, this number may differ from the absolute humidity based on the goal temperature.

o The user is responsible for choosing the humidity source and opening the appropriate valve. If no valve is opened, the air pump may fail. If the wrong humidity source is chosen, the humidity will not reach the defined range.

o There are other variables within the program that are related to humidity. DO NOT CHANGE any variables except the ones in the section labeled “INPUT ALL VARIABLES HERE”, unless you are intentionally customizing the way the code functions to better suit your needs. If you do choose to customize your code, we recommend saving the original version under a different filename, in case you need to return to it.

Temperature

· Name in the ECOTech code: temp

· Purpose: User inputs this value as the target temperature of the main chamber.

· Use: Input the desired temperature for your experiment, in degrees Celsius. When uploaded, the program will read the humidity and temperature every five seconds. If the actual temperature is lower than the defined range, the heat gun will blow warm air into the main chamber. When the temperature has reached the upper limit of the defined range, the heat gun will turn off.

· NOTES:

o This value is the target temperature in degrees Celsius, not Fahrenheit, Kelvin, or Rankine. As such, you may need to convert this value to the correct units.

o Due to air flow and sensor lag, the temperature may continue to rise a few degrees after the heat gun has turned off. To account for this, a lower tolerance can be set by the user.

o There are other variables within the program that are related to temperature. DO NOT CHANGE any variables except the ones in the section labeled “INPUT ALL VARIABLES HERE”, unless you are intentionally customizing the way the code functions to better suit your needs. If you do choose to customize your code, we recommend saving the original version under a different filename, in case you need to return to it.

Humidity Tolerance

· Name in the ECOTech code: humTol

· Purpose: Creates an acceptable humidity range for the user’s needs.

· Use: Input a tolerance value, in percent relative humidity. This will create an acceptable range of humidities for the internal environment of the main chamber. For example, if the humidity is set to 65 and the humidity tolerance to 5, then the system will switch on the humidity adjustment system when the humidity dips below 60 percent, or rises above 70 percent. This tolerance value can be set as low as zero for experiments that require high precision, or another value to account for a margin of error in the humidity delivery system. · NOTES: o This tolerance value is in percent relative humidity, not absolute humidity or a percent error.

Temperature Tolerance

· Name in the ECOTech code: tempTol

· Purpose: Creates an acceptable temperature range for the user’s needs.

· Use: Input a tolerance value, in degrees Celsius. This will create an acceptable range of temperatures for the internal environment of the main chamber. For example, if the temperature is set to 40 and the temperature tolerance to 3, then the system will not switch on the heat gun until the temperature dips to 37 degrees, and will continue until the sensor reads 43 degrees. This tolerance value can be set as low as zero for experiments that require high precision, or greater than zero to account for the slight rise in temperature that can be caused by radiation from the metal piece in the back of the main chamber.

· NOTES:

o This tolerance value is in degrees Celsius, not a percent error.

Performance

Both the temperature adjustment and humidity adjustment systems are time-consuming. The temperature adjustment system can reach any temperature up to 60 degrees Celsius in roughly an hour or less, as shown in Figure 5. The humidity system may need to run for several hours in order to reach the defined range.

Troubleshooting

Code:

• If the code will not verify, it is most likely an error in the code text, or the location of the sensor libraries. Review the Setup Instructions and ensure that all steps were followed correctly.
• If the code will not upload, go to Tools and make sure that a Port was selected before trying again.
• If the code does not function as intended, upload an older version of the file if possible. ·

Temperature or Humidity:

• If the temperature or humidity are not reaching the intended temperature, double-check the user-controlled variables, especially the temperature and humidity tolerances.