Ferrofluid Art Display - Revision history

CaitlinPowersMaher: /* Reflections */

2010-03-19T14:37:50Z

Reflections

← Older revision		Revision as of 09:37, 19 March 2010
Line 518:		Line 518:

	By our mid-project milestone, we were able to control several solenoids individually through a PIC-to-PC interface, and were close to achieving the same results on our 19 element array.		By our mid-project milestone, we were able to control several solenoids individually through a PIC-to-PC interface, and were close to achieving the same results on our 19 element array.

	In addition to all of our technical achievements, we also made great strides in overcome both intellectual and personal challenges, and were able to keep the team together and working towards a common goal. Although difficult at times, we ultimately feel that this project and this class were both an enjoyable and educational experience and plan on recommending it in future years to come.

ToddPoole: /* Electrical Design */

2010-03-19T11:45:14Z

Electrical Design

← Older revision		Revision as of 06:45, 19 March 2010
Line 128:		Line 128:
	{{multiple image		{{multiple image
	\| width = 100		\| width = 100
	\| footer = A custom differential op-amp shifting and scaling circuit

	\| image1 = TP_KP_MW_ShiftAndScaleCircuit1-resize.jpg		\| image1 = TP_KP_MW_ShiftAndScaleCircuit1-resize.jpg
	\| alt1 = The math ~~and derivations~~ behind the ~~shifting and scaling~~ circuit		\| alt1 = The math behind the circuit
	\| caption1 = The math ~~and derivations~~ behind the ~~shifting and scaling~~ circuit		\| caption1 = The math behind the circuit

	\| image2 = TP_KP_MW_ShiftAndScaleCircuit2-resize.jpg		\| image2 = TP_KP_MW_ShiftAndScaleCircuit2-resize.jpg
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	\| caption2 = The circuit schematic and necessary resistor values		\| caption2 = The circuit schematic and necessary resistor values
	}}		}}
	Additionally, we used a ~~shifter~~ ~~and~~ ~~scaler~~ circuit to shift an ~~external audio~~ ~~source~~ in the [-2V,+2V] range to to [0V,4V] range, and then ~~compress~~ it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.		Additionally, we used an LM741 operational amplifier to construct a circuit that would both shift an input waveform in the [-2V,+2V] range to to [0V,4V] range, and then scale it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.

	This circuit required:		This circuit required:

ToddPoole: /* Electrical Design */

2010-03-19T11:43:24Z

Electrical Design

← Older revision		Revision as of 06:43, 19 March 2010
Line 126:		Line 126:
	*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.		*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.

			{{multiple image
⚫	~~[[Image:TP_KP_MW_ShiftAndScaleCircuit1-resize.jpg\|thumb\|150px~~\|The math and derivations behind the shifting and scaling circuit]]
			\| width = 100
⚫	~~[[Image:TP_KP_MW_ShiftAndScaleCircuit2-resize.jpg\|thumb\|150px~~\|The circuit schematic and necessary resistor values]]
			\| footer = A custom differential op-amp shifting and scaling circuit

			\| image1 = TP_KP_MW_ShiftAndScaleCircuit1-resize.jpg
		⚫	\| alt1 = The math and derivations behind the shifting and scaling circuit
			\| caption1 = The math and derivations behind the shifting and scaling circuit

			\| image2 = TP_KP_MW_ShiftAndScaleCircuit2-resize.jpg
		⚫	\| alt2 = The circuit schematic and necessary resistor values
			\| caption2 = The circuit schematic and necessary resistor values
			}}
	Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.		Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.

ToddPoole: /* Electrical Design */

2010-03-19T11:41:25Z

Electrical Design

← Older revision		Revision as of 06:41, 19 March 2010
Line 126:		Line 126:
	*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.		*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.

	[[Image:~~TP_KP_MW_Sketch04~~-resize.jpg\|thumb\|150px\|A ~~single~~ ~~solenoid~~ in ~~its~~ ~~housing~~]]		[[Image:TP_KP_MW_ShiftAndScaleCircuit1-resize.jpg\|thumb\|150px\|The math and derivations behind the shifting and scaling circuit]]
			[[Image:TP_KP_MW_ShiftAndScaleCircuit2-resize.jpg\|thumb\|150px\|The circuit schematic and necessary resistor values]]
	Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.		Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.

ToddPoole: /* Electrical Design */

2010-03-19T11:34:58Z

Electrical Design

← Older revision		Revision as of 06:34, 19 March 2010
Line 126:		Line 126:
	*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.		*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.

			[[Image:TP_KP_MW_Sketch04-resize.jpg\|thumb\|150px\|A single solenoid in its housing]]
	Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V].		Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V] so that we could process the waveform with our PIC's analog to digital converter.

	This circuit required:		This circuit required:

ToddPoole: /* Electrical Design */

2010-03-19T11:33:38Z

Electrical Design

← Older revision		Revision as of 06:33, 19 March 2010
Line 129:		Line 129:

	This circuit required:		This circuit required:
	*1x LM741 op-amp		*1x LM741 op-amp, obtained in the NU Mechatronics Lab, free of charge.
			*1x 300kOhm Resistor, obtained in the NU Mechatronics Lab, free of charge.
			*1x 400kOhm Resistor, obtained in the NU Mechatronics Lab, free of charge.
			*2x 100kOhm Resistor, obtained in the NU Mechatronics Lab, free of charge.
			*1x 200kOhm Resistor, obtained in the NU Mechatronics Lab, free of charge.
			*1x 185kOhm Resistor, obtained in the NU Mechatronics Lab, free of charge.

	==Code==		==Code==

ToddPoole: /* Electrical Design */

2010-03-19T11:29:51Z

Electrical Design

← Older revision		Revision as of 06:29, 19 March 2010
Line 125:		Line 125:

	*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.		*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.

			Additionally, we used a shifter and scaler circuit to shift an external audio source in the [-2V,+2V] range to to [0V,4V] range, and then compress it to [0v,3V].

			This circuit required:
			*1x LM741 op-amp

	==Code==		==Code==

ToddPoole: /* Electrical Design */

2010-03-19T11:27:03Z

Electrical Design

← Older revision		Revision as of 06:27, 19 March 2010
Line 112:		Line 112:

	Our electronics system consisted of:		Our electronics system consisted of:
	*~~One~~ NU32 board: [[Introduction to the PIC32]]		*1x NU32 board: [[Introduction to the PIC32]]
	*19 solenoids: [https://www.jameco.com/webapp/wcs/stores/servlet/OrderItemDisplay?langId=-1&storeId=10001&catalogId=10001&krypto=WUgCYelA18EFMkT03NuyYowmviur5pLw5O7ybblUbPU1s%2BE5iJH6qHHMpTSj4RJNARBe7J9MvmE%3D&ddkey=https:OrderItemUpdate Jameco Part #262271]		*19x solenoids: [https://www.jameco.com/webapp/wcs/stores/servlet/OrderItemDisplay?langId=-1&storeId=10001&catalogId=10001&krypto=WUgCYelA18EFMkT03NuyYowmviur5pLw5O7ybblUbPU1s%2BE5iJH6qHHMpTSj4RJNARBe7J9MvmE%3D&ddkey=https:OrderItemUpdate Jameco Part #262271]
	*10 L293NDE Quad-half-bridges: [http://www.datasheetcatalog.com/datasheets_pdf/L/2/9/3/L293DNE.shtml Datasheet]		*10x L293NDE Quad-half-bridges: [http://www.datasheetcatalog.com/datasheets_pdf/L/2/9/3/L293DNE.shtml Datasheet]
	*5 SN74HC00N NAND Integrated Circuits: [http://www.chipsinfo.com/TI/SN74HC00N.htm Datasheet]		*5x SN74HC00N NAND Integrated Circuits: [http://www.chipsinfo.com/TI/SN74HC00N.htm Datasheet]

	[[Image:circuit_diagram.png]]		[[Image:circuit_diagram.png]]
Line 125:		Line 125:

	*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.		*The H-bridge is also connected to the enable voltage. Controlled by the PIC, the enable voltage, when high, would allow current to flow through the half-bridges. When low, no current would flow. This made it so that current would not flow at all times, just when the solenoids were switching position.

	Picture of circuit for 4 solenoids goes.

	==Code==		==Code==

ToddPoole: /* Reflections */

2010-03-19T11:25:51Z

Reflections

← Older revision		Revision as of 06:25, 19 March 2010
Line 488:		Line 488:

	== Reflections ==		== Reflections ==
			While our Ferrofluid Art Display was a great first step towards bringing ferrofluid visualization under computer control, there are several ways one could continue our work where we left off and extend our design. We've identified three specific areas we would have liked to explore further, had we had more time.
	Todd

			The first being the strength of our magnetic fields. We initially planned for a pair of magnets to reside on each solenoid, but in testing we found that the neodymium iron boron magnets were simply too strong (or the pull force of our solenoids was too weak) to retract the rod after it had been extended (the rod would sometimes remain extended, even with the solenoid pulling it down, due to the magnetic attraction between the neodymium iron boron magnet and the underside of the fluid tray). We overcame this problem by reducing the number of magnets on each solenoid from two to one. However, if we had more time, we would have like to try out stronger solenoids if we could find any for roughly the same price, weaker magnets but with the same surface area (magnetic field strength is heavily influenced by the area of the surface normal to the point of interest), or perhaps an alternative return mechanism for our rod (such as a spring, or even replacing the solenoids altogether with high torque hobby servos).

			Another area we would like to explore involves scaling the dimensions of our housing up and seeing what kind of performance we get out of the fluid with larger distances between each magnet. During our testing, we noticed that some magnets were being pushed along the walls of their individual silos by their neighboring magnets. While it wasn't extreme, the friction did occasionally cause a rod to catch and delay an extension or retraction.

			Lastly, we'd also recommend the possibility of synthesizing ferrofluid in Northwestern's Chemistry Department at reduced prices and larger quantities. Two weeks were devoted to the synthesis of a usable fluid, and the best we were able to come up with was a rest-colored viscous syrup, a fluid far inferior to what we were able to obtain commercially. After consulting with some the Chemistry Department, it appears the fluid we synthesized in the lab contains magnetite particles that are simply too large (1 to 1000 micrometers) compared to what one could obtain from a chemical supply company (.4 to 10 micrometers). This difference in size is the most likely explanation for the increase in viscosity for our homemade ferrofluid.

			Having pointed out these three areas of improvement for further exploration, we still largely consider our project a success. Over the course of three and a half weeks, we learned an extraordinary amount of information about magnetic fields, solenoids, H-Bridges, MPLAB, and Processing, and we became much more familiar with many of Northwestern's shop equipment including the laser cutter, the lathe, and CNC mill. We learned a little bit of chemistry in our pursuit of a cheaper ferrofluid, we learned about op-amps and transistors in our early attempts at figuring out how to individually actuate each solenoid, and we learned about how versatile the NU32 PIC can be.

			By our mid-project milestone, we were able to control several solenoids individually through a PIC-to-PC interface, and were close to achieving the same results on our 19 element array.

			In addition to all of our technical achievements, we also made great strides in overcome both intellectual and personal challenges, and were able to keep the team together and working towards a common goal. Although difficult at times, we ultimately feel that this project and this class were both an enjoyable and educational experience and plan on recommending it in future years to come.

ToddPoole: /* Final Design */

2010-03-19T11:25:39Z

Final Design

← Older revision		Revision as of 06:25, 19 March 2010
Line 82:		Line 82:

	After both layers of plywood were milled out by the CNC machine, they were joined together with wood screws, and small holes were drilled down the cylindrical axis of each well to allow for the control wires for each solenoid to pass through the housing.		After both layers of plywood were milled out by the CNC machine, they were joined together with wood screws, and small holes were drilled down the cylindrical axis of each well to allow for the control wires for each solenoid to pass through the housing.

			Before leaving the CNC machine, the same hexagonal outline used to mill the wooden housing was reused to mill the outline of the polycarbonate fluid tray that sits above the solenoids. Care was taken to ensure that the milling instructions for each well inside the CNC's program memory was skipped, leaving only the instruction to mill the hexagonal pattern.

	Once this was completed, we used a band saw to help strip each solenoid of its iron housing (which interfered with the magnetic field set up by the neodymium magnets), and inserted each element into its designated well.		Once this was completed, we used a band saw to help strip each solenoid of its iron housing (which interfered with the magnetic field set up by the neodymium magnets), and inserted each element into its designated well.