final project idea
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for my final project, i am thinking about making a couch with a lot of extra features and gizmos that can be controlled by control pads located on the arm rests.
i'm thinking about using the make something big week to prototype making the frame of the couch using a higher quality plywood.
the wildcard week, i'm hoping to explore more of the textiles that will be involved in the project, and figuring out how to get them to heat safely and to varying amounts.
maybe even get some foot rests to pop out to incorporate some mechanical machine design.
it's still a work in progress, but these are my initial thoughts
it's a couple weeks later, and i have a more complete concept of what i'd like to do for the final project now. instead of doing a couch, i'd like to do a pair of chairs that are rigged out with a extra features and gizmos on the armrests.
one one side of the armrest, i'd like to make a coffee mug warmer. this would be operated through a thermistor input device and heating pad output device. it will read in the temperature that the mug is at, and if it goes below a certain temperature, the heating mechanism will automatically turn on to keep my drink warm. on the other side of the armrest, i'd like to make a phone charger. this would be operated through a step resonse input device and some sort of induction coil charging device. it will be able to sense when my phone is on the device, and then be able to charge it.
i would also like to make it bluetooth operated as well, i don't want the heating mechanism to always be running at a certain temperature (since the majority of the time it will be colder than a hot coffee when not in use), so i'd like to be able to remotely turn it off and on. this wouldn't affect the heating cycle it does through the input and output device though, that should still be automatic.
some things i still need to figure out are how i'd like to power these devices (i don't particularly want to plug it into a computer or wall, but i may have to do that).
i have used the input device week to test out a thermistor, and i hope to use the output and networking weeks to explore some other aspects of this final project.
in my meeting with one of the TAs, we discussed the scope of the project and more about how to tackle my biggest hurdle (which will be the electronics) and incorporate networking devices. i'd also like to make seat cushions (at some point i thought i would want to make these heated, but that's a later problem that i could add in if i want), and maybe even do some embroidery on them to spice them up!
the notes from our discussion:
he also recommended that i do maybe a step response for the coffee mug, but i may try to keep the thermistor, because i think that's a more precise problem i'd like to tackle to keep my coffee hot.
another part of the project, and why i will be making two chairs, is because i'd like to test out a concept that i am learning in another one of my classes, topology optimization. I would like to make a topology optimized chair, and see how i can keep the stiffness and stability of the chair, while removing unnecessary material. examples of topology optimized chairs:
then i tried to program them as master and slave. my master circuit was the input circuit which would send data to my slave output circuit which would receive the data. the code says that if the thermistor reaches above a certain temperature, then it will send "1" to the serial monitor and turn the RBG light on the output circuit on Red, and if the temperature is less than that certain temperature, it will send "0" to the serial monitor and turn the RBG light blue. the code i used to program these are shown below:
there were problems with this. i was able to connect the two circuits together, and my thermistor would be reading temperature and outputting 0s and 1s in the serial monitor, but the RGB light was not changing color. i was also having trouble with my power source.. i would connect the two boards, and the board would start smoking?? i made sure i was connecting in the correct orientation, so i'm not sure if my power source was too large? i will definitely be going to the eecs office hours to get this figured out so i can get some more progress for my final project
next, i'll be trying to connect the heat source:
heat source
(week 11) so this week, i decided to focus on getting the heating element on my board to work. this involved designing a main board with the microcontroller, and a couple of side boards that took some of the elements off to the side that could be placed anywhere in the final product. the board consisted of a button, an RGB led, an external power source, and the external heating element.
after it was milled and soldered, i attempted to program the board. first, i wanted the button and RGB led to work, because i've done that before, and wanted to make sure my board worked in general -- and success!
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next, i worked to get the heating element work. this is where all the problems/solutions happened. on the board, i installed a mosfet to act as a switch to the heating element. i wanted to be able to call on the pin to only turn on the heating element when my button was pressed.
the first iteration of problems was that my heat element was designed for 12v while the microcontroller is only designed for 5v. plugging in the external power source at 12v to the board fried my attiny44 -- had to be replaced and redesigned. just to continue testing purposes, i replaced the attiny44, and broke the voltage connection between the heating element, external power source, and the rest of the board. this should have worked, but not enough amps were getting to my heating element. this i learned, was due to the incorrect mosfet being used. during testing with a voltmeter, when the mosfet was being bypassed, the heating element would heat up!! the mosfet i was using didn't have the amount of amps available to send the 3-4 amps of current needed for the heating element to get as hot as i needed it to be. the external power source was still plugged in, and my mosfet eventually burned -- a little scary honestly.
next steps are to re-mill the board with the necessary changes, and do another test that will hopefully work. also, i'd like to add a thermistor to be able to program the heating element to automatically turn on once a certain temperature is reached. testing of the thermistor has already been conducted in previous weeks, so hopefully not too much will have to be done. I do remember almost having an issue of memory when programming the thermistor using Arduino, so maybe I will also upgrade to an attiny84.