Week 9: Finished Chair Assembly and Worked out DAQ Kinks

During this week of our project, the assembly of the chair and all of its part is for the most part completed. We are still continuing to work on the cod However, there were some issues with getting the DAQ to output signals that were taken from the electrodes that were placed on the skin. When we tried to obtain a signal and see the graph that was produced from it there was no graph produced. Also, instead of the line of the graph staying at 0 when no motion was being made in the neck there was some drifting in the data. The drift would occur between -10 and 10. Many different approaches were taken about how to fix this problem and get an output to come out. But, this past weekend most of these problems that we were having were solved. We were able to get signals from two of the sensors instead of getting signals from all four. To generate a strong signal the biceps of one of the group members had to be used. To solve the issue of the data drifting from -10 to 10 the sensors were placed further apart from each other and the drifting was fixed. We also modified our code to be able to see two graphs, one graph for each set of sensors, instead of just one. This could not fully be tested, but we do not see any reason why this would not work. We now need to set a threshold that when reached will send a signal to the DAQ, through the circuit, to the battery and they to the motor that will move the chair up or down. In Figure 1 below is a photograph of the final design project.

 

Figure 1: Final design of the chair.

    

Week 8: Chair assembly and Electrical Component Testing

During this week of our project, we finished getting all of the parts necessary for building, and we continued building the chair. We are planning to finish it by the end of this week. Along with the assembly of the chair, the electrical components have been put together, but they still need to be tested to make sure that they are working properly. For the code, we are working to get outputs. We are making a lot of progress with our project.

Week 7: Began assembling Chair and Getting Electrical Components together

During this week of our project, we focused on putting the amplifier together and improved it so it could have a gain of 3000. We also obtained the last of the parts that were needed to put the chair together. The wires needed to collect the EMG signals were also made along with the wires to connect the amplifier to the DAQ. Finally, we got the sensors (electrodes) that were needed for us to obtain the EMG signals from the neck. The drivers that were needed for the DAQ to work properly were also downloaded this week.WE are also making a trip to Home Depot to get more supplies.

Week 6: Worked on Questions and Electronic Components

During this week of our project, we worked on a set of questions that we were presented with. The questions dealt with knowing how the different components of the project will all work together to supply us with a functioning final project. Also during this week, we worked on getting the final aspects of the electrical component of the project complete. After receiving the sample MATLAB code, several of the group members also started working on the code which will interpret the signals that are coming in from the electrodes, and properly process them so that the linear actuator will behave properly. For this coming week, we plan on starting to assemble the mechanical components which will make up the chair.

Week 5 Finalized Design

This week we finalized the design for the chair and linear actuator assembly. Made minor modifications to the design by deciding on a way to mount to linear actuator and also a way to allow the seat to still swivel in addition to being able to move up and down. Still waiting for linear actuator to come in the mail so that work can be done to build the prototype.

Week 4 Ordered Parts

This week we drew up plans for the electric circuits that will be used for this project. Discussed how to use amplifier and the relays that we ordered. Purchased necessary parts including linear actuator, transistor, dual pole relay, single pole relay.

Week 3: Start of Project

This week we got our chair that we will be modifying for the project. Also we complied a list of materials that we need for the project. The MatLab code is also underway, with a rough outline of what it is supposed to do and how it is supposed to look. The design of the chair has been made in ProEngineer so that we can make modification from there, and model the design using ProEngineer.