https://wiki.mcmaster.ca/EP3A03/ Tue, 10 Nov 2026 23:32:19 -0500 FeedCreator 1.7.2-ppt DokuWiki https://wiki.mcmaster.ca/EP3A03/lib/images/favicon.ico https://wiki.mcmaster.ca/EP3A03/ https://wiki.mcmaster.ca/EP3A03/group2:budget?rev=1228856859&do=diff Parts Used Note: The total shipping costs from digikey came to $8.00 between the three groups. one star These parts were taken from the 4A04 lab room. The costs were estimated using either the EP4A04 course outline or online sources. two stars These parts were previously owned. Cost was estimated from online sources. group2 Tue, 09 Dec 2008 16:07:39 -0500 https://wiki.mcmaster.ca/EP3A03/group2:demonstration_and_results?rev=1228858372&do=diff For the final demonstration four optical sources were selected: a red LED, a yellow LED, a green LED, and a blue LED. The sources were inserted to be analyzed randomly. The program Hyperterminal was set to record and the spectrometer was turned on. The stepper motor rotated the bolt which translated the photodiode across the spectrum. The PIC microcontroller received the analog readings from the photodiode and converted them into a digital value. This value was transmitted via the RS232 connecti… group2 Tue, 09 Dec 2008 16:32:52 -0500 https://wiki.mcmaster.ca/EP3A03/group2:electrical_design?rev=1228858128&do=diff The PIC16F818 microcontroller will be used to control the stepper motor, acquire data, and send it to a laptop via a serial interface. The stepper motor has a permanent magnetic core, which is arranged in alternating north-south “pie slices”. The picture below shows what this core looked like, along with the two coils which rotate it. When a current is applied the magnets will be attracted to the coil, depending on the direction of the current. By altering these currents in a specific fashion, i… group2 Tue, 09 Dec 2008 16:28:48 -0500 https://wiki.mcmaster.ca/EP3A03/group2:electrical_proof-of-principle_outline?rev=1228848665&do=diff The principle to be tested consists of three parts. The first is the stepper motor-control, second is the photodiode detection of light, and the third is the serial communication with the microcontroller. For the first test the microcontroller was programmed to emit four square wave signals, each connected to two BJTs, that provided current for a particular wire from the motor. The stepper motor has two windings that generate a magnetic field when a current is passed through. By alternating cur… group2 Tue, 09 Dec 2008 13:51:05 -0500 https://wiki.mcmaster.ca/EP3A03/group2:final_design?rev=1223252633&do=diff Proposed Design The spectrometer design which was chosen uses a prism to disperse visible light. The refractive index of the prism depends on the wavelength of light: red light will have a smaller refractive index than violet light. Since the light will leave the prism at different angles depending on the wavelength, it will be possible to use physical geometry to monitor the refracted light, and record a spectrum. The proposed design consists of three stages: group2 Sun, 05 Oct 2008 20:23:53 -0500 https://wiki.mcmaster.ca/EP3A03/group2:final_design_-_pre-build?rev=1223254251&do=diff Proposed Design The spectrometer design which was chosen uses a prism to disperse visible light. The refractive index of the prism depends on the wavelength of light: red light will have a smaller refractive index than violet light. Since the light will leave the prism at different angles depending on the wavelength, it will be possible to use physical geometry to monitor the refracted light, and record a spectrum. The proposed design consists of three stages: group2 Sun, 05 Oct 2008 20:50:51 -0500 https://wiki.mcmaster.ca/EP3A03/group2:final_design_details?rev=1228857416&do=diff There are two accessible methods to disperse light and study its spectrum: dispersion using a diffraction grating and dispersion using a prism. There are certain advantages and disadvantages to both methods. The diffraction grating produces a wider angle of dispersion (the resulting spectrum is much wider than that of a prism, making it easier to work with), but produces several orders of the spectrum. These orders do not usually interfere with each other, unless they are of a higher order, but … group2 Tue, 09 Dec 2008 16:16:56 -0500 https://wiki.mcmaster.ca/EP3A03/group2:final_product_description?rev=1228856591&do=diff The response curve of the chosen diode (solid curve) is shown in Figure 2. Figure 2: BCS2015G1 Response Curve The diode will be mechanically moved across the whole spectrum, and will then provide information about position vs intensity. The system in Figure 3 will be used to translate the diode. group2 Tue, 09 Dec 2008 16:03:11 -0500 https://wiki.mcmaster.ca/EP3A03/group2:group2start?rev=1228856629&do=diff Weekly Reports Final Design - Pre-Build System Components Details Optical Proof-of-Principle Outline Electrical Proof-of-Principle Outline Objectives Final Design Details Final Product Description Demonstration and Results Budget group2 Tue, 09 Dec 2008 16:03:49 -0500 https://wiki.mcmaster.ca/EP3A03/group2:group2weekly?rev=1228698640&do=diff Week 13: Nov 24 - Nov 28 The enclosing box was built out of scrap wood. The components were mounted to the base, and the motor was hooked up to the circuit board. A switch was added to turn the power on and off. Hyperterminal was utilized to communicate with the micro controller. Sevceral tests were run to detrmine the spectrums, and the microcontroller was programmed to scan the spectrum while gathering data, and then rewind. A light enclosure was built to allow no ambient light into the syste… group2 Sun, 07 Dec 2008 20:10:40 -0500 https://wiki.mcmaster.ca/EP3A03/group2:objectives?rev=1228716574&do=diff The purpose of our spectrometer is to differentiate four different colored LED's. The make spectrum of the LED's will be displayed in order to tell which color they are. group2 Mon, 08 Dec 2008 01:09:34 -0500 https://wiki.mcmaster.ca/EP3A03/group2:optical_proof-of-principle_outline?rev=1224813403&do=diff The optical proof of principle will demonstrate the refractive properties of a glass prism, whose refractive index depends on the wavelength of light. The test will demonstrate the optical equipment mounting mechanisms which are adopted for this design, as well as the effectiveness of the prism to separate different colored LED’s. group2 Thu, 23 Oct 2008 21:56:43 -0500 https://wiki.mcmaster.ca/EP3A03/group2:pictures?rev=1226810743&do=diff You can see the heat dissipation holes on one of the plywood pieces: this is where the motor will be mounted. ---------- ---------- ---------- ---------- ---------- group2 Sat, 15 Nov 2008 23:45:43 -0500 https://wiki.mcmaster.ca/EP3A03/group2:system_components_details?rev=1226809296&do=diff This section will list the various components, such as microcontrollers, diodes, prisms, etc. By clicking on the links below you will be able to access technical details and pictures: * Pictures * Comments * Specifications group2 Sat, 15 Nov 2008 23:21:36 -0500