Design team members: Devon Galloway, Gary Abbott, Tyler Reh
Supervisor: Justin Eichel
Background
A barbeque is a very common instrument for cooking in North America. Essentially, a barbeque consists of a metal or porcelain-covered metal grill placed over a heat source. The heat source in most barbeques is either natural gas or liquid propane. In a basic barbeque, the user controls the amount of natural gas or propane that is burned using valves mounted on the front of the barbeque to control the temperature.
One of the main problems with this method of cooking is that it can be inconsistent due to the many factors that can affect the cooking temperature. The external temperature, the seal of the grill hood, and the number of times that the hood is opened are just a few examples of external factors that can cause errors. Also, the temperature can vary around the grill itself. For example, grease from the meat can cause flames to flare up and create hot spots around the cooking surface.
After extensive research, not one solution that would be capable of managing these issues to produce a consistent cooking experience. While there exists products and patents such as meat thermometers and grill temperature sensors, no one has created a complete system to control the whole cooking process.
Project description
The goal of the project is to create a barbeque temperature control system that will help the user to produce consistent cooking results. The user will enter the type of food they will be cooking and to what degree they would like that food cooked (rare, medium, etc.). The design will then control the natural gas or propane in order to maintain a predetermined temperature profile across the barbeque. The system will also let the user know what actions are required and when they should be performed. For example, when cooking a burger, it will let you know when to flip it and then when to remove it.
This project will look to improve the user experience while barbequing. By partially automating the cooking process, it will reduce the amount of time someone will have to check the food and temperature. It will also reduce the knowledge requirements of the user. For example, an inexperienced person would find it difficult to tell the difference if a steak was medium-rare or medium-well without cutting it open to see the centre. This project will take the guess work out of cooking, as the consistent results will be pre-programmed into the control system. Even a novice user will be able to cook with confidence and produce high-quality, consistent results with minimal effort.
Design methodology
In order to create this system, several design solutions were considered. The design that was ultimately selected and will be prototyped can be split up into 4 main parts. The first is the grill temperature input. The temperature inside the grill will be measured by several thermocouples mounted inside the barbeque. This information is then amplified and conditioned with a small electrical circuit. The second part is the valve control system. Servo motors will be attached to the existing barbeque valves in order to control the amount of gas that is burned, which subsequently controls the temperature. These servos will allow the user to also use the barbeque manually without the control system, like one would on a standard barbeque. The third part is the user interface. An LCD will be used to display to the user the temperature, the cook timer, and any actions that are required from them. To allow the user to input information, a simple 3 button system will be used with controls for up, down, and enter.
All three parts are fed into the fourth and final part, the basic stamp. A basic stamp is essentially a mini-computer. This will be the brains of the operation, which will take the user and temperature inputs and calculate how the food will be cooked. Once the cooking temperature and schedule are determined, the basic stamp will then control the servos to set the desired temperature. The LCD will display the cooking information for the user, as well as when to flip and remove the food. The whole system will sit in a small box that is stored on the barbeque. Additionally, the entire control system will run off a single 9V battery, allowing the barbeque to remain mobile.