January 12, 2006 (1 hour):
After class the group met up to discuss our preliminary project proposal. We initially discussing the project with Professor Meyer, and after a go ahead we began dreaming up what our device could do. We decided that our project should identify users, track their statistics, control and monitor temperature, control and monitor flow amount, have a web based interface, and an have a LCD interface on the device. As a group we completed homework one and discussed our individuals strengths. I suggested we control the temperature using a temperature probe and a contactor on the AC Compressor. We need to talk to Professor Myer since this device will use AC Power. Finally each one of us described which parts of the project we would like to work on. I think I will work on the PCB layout and assist with the hardware interconnect.
WEEK 01 SUMMARY
Accomplishments: Picked a Project idea, Brainstormed project functions. Completed Homework 1.
Weekly Work Total: 1 hours
Project Work Total: 1 hours
January 16, 2006 (4 hours):
I spoke with my father who used to work at Potter and Brumfield about contactor operation. After getting a solid feeling of how they function I began searching at Newark for a suitable contactor. As I was looking several questions came to my mind. Where should we mount this contactor? Will the location cause size constraints? To determine this I would need to measure inside the fridge near the compressor. I also need to determine the contactor current rating. Matt had told me the freezer in the HKN lounge is identical to the one we are going to use. After looking at this device it appears the device has 5 Amp current draw. I decieded I would play it safe and get a contactor with a max current rating around 20-30 Amps. I still need to determine how to interface the device to the micro and what voltage should to use. This contactor is going to involve buying a power supply for our device to create these drive voltages. That evening we met together and shared our results. I drew this rough block diagram of our system to summarize our ideas. simple functional sketch.
January 17, 2006 (1 Hour)
Today I went and spoke with Professor Meyer about using AC Power in our system. I explained to him what I wanted to do and I ask how I could interface the contactor with the micro. He pointed me to 362 Module 4. After looking over this module its clear I will need to review my EE 255 notes.
January 19, 2006 (4.5 hours):
I visited Mattís and Ianís Apartment to see the freezer chest we are going to use for the project. I took measurement of the whole container and internal measurements near the compressor compartment. Here is a link to a rough sketch I drew of the freezer chest Fridge Dimensions From analyzing the compartment I was able to narrow down the size of contactor we would need to use. I found the OMRON PN: 89C7158 would satisfy our requirements. This device is single pole single throw contactor that is normally open. It would require a 12 Vdc drive to initiate the contacts and its size from the data shee is 2.5 in x 2.5 in x 2.2 in. This size would fit perfect inside the compressor compartment. Here is the link to the data sheet. OMRON Contactor Data sheet
WEEK 02 SUMMARY
Accomplishments: We have narrowed down our functionality requirments. I located a suitable contactor based on the dimensions and the requirments of the freezer.
Weekly Work Total: 9.5hours
Project Work Total: 10.5 hours
January 22, 2006 (4 hours):
We met again as a group to discuss our results. As a group we wrote Homework 2. After that I went to the lab and created a Visio block diagram for Homework 2. This block diagram can be found here. Block Diagram for HW2
January 24, 2006 (4 hours):
I finished updating my journal entries on our website. I also looked into an AC to DC converter for our project. This device would take 120VAC and create 5V, 12V, and -12V. This device would work well with our micro and would also be great for the contactor device which requires a 12 V Input. This device is from a company called Toko, and its sold thru Digi-Key. I was hesitant to use this part in the beginning because there was no datasheet on the website. However after contacting Digi-Key they were able to find me data sheet. Here is the AC to DC converter Data sheet that I think that would meet our Power Supply Data sheet I am trying to persuade Matt to choose a 12V Solenoid Device so it would be compatible. I still need to look into BJT and MOSFETS for the interfacing of this contactor.
January 25 2006 (1 hours):
After class we met Chuck Barnett in the lab and he gave us our Rabbit Development Kit. I believe we are a go for the Rabbit 3315. I also talked with the TA Nick about the Power Supply. I told him which device I had picked out and I wanted to know if that would be acceptable. He told me it would be alot easier to use a wall mount or in line transformer inconjunction with an on board device.
January 26 2006 (2.5 hours):
After reviewing what Nick had said I was trying to picture how this might work. If we were to use a wall wort we would have to have to use two plugins instead of one. I was hoping we could splice i I caught Professor Meyer after class and I him asked just this question. Professor Meyer explained that we would need a wall wort but it can be done inside of the device. One idea is to use a a breakout box. I think I will try this approach. I then began searching for Power Supplies but I soon discovered that its important that I know all the current levels of our major parts. Later in the evening we met as a group to share what we had been working on. I asked them the group their current requirements. I calcualated that we would need at least 5 amps for our Power Supply. I leaning toward a device very similiar to this one now. AED100US12 Matt also brought up the idea of having a dollar bill reader for the device. I think this is a great idea but I don't know what current requirements it will add to our device.
WEEK 03 SUMMARY
Accomplishments: We finished hw2 and nailed down our project sucess criteria. We also got our Development Board for the Rabbit. I learned an incredible amount about power supplies and I am leaning toward a choice.
Weekly Work Total: 11.5 hours
Project Work Total: 23 hours
January 30 2006 (2 hours):
I looked into compressor motors on the internet and it appears they are AC split-phase devices. One of the interesting websites I found was the Fridge doctor. I learned that compressors have high inrush currents intially when they are starting. Also the more times a compressor cycles the more wear it is on the system. From this information I think we need to choose a contactor with a high current rating and software should have a hysteris loop to minimize the number of system turn ons. After talking to the TA's about my contactor choice I ordered the 89C7158 from Newark.
February 1 2006 (1.5 hours):
After our 362 Power Supply Lecture today I thought it would be important to find and on board power supply. Our project is going to use two power supplies now. One device will be a transformer that rectifies 120 VAC to 12VDC. This power will be dirty and we will use this for our contactor, flow valve solenoids, and dollar bill acceptor. The other power supply I picked out converts a dirty 12 to a regulated 5V and 3.3V. The Power Supply I found from Digikey is the following and it looks promising. Maxim On Board Power Supply I also received the contactor today from Newark. It fits in the palm of my hand.
February 2 2006 (3 hours):
Today we decided to meet at Mat and Ian's house. As a group we went through the LCD menu system. Matt has a picture of the basic menu system we designed. We began sketching out a new block diagram on my tablet but i am going to wait until I can put it in Visio. I finalized my power requirements and I have included my calculation spreadsheet here. Power Supply Calculations
February 4 2006 (5.5 hours):
We decided to meet in the lab saturday at 5. Ian and Matt notifed me of the problem with dynamic C. Matt and I discussed our external interrupt with the flowmeters. As a team we debated the operation of normally open vs normally closed solenoid valves. Matt would rather have the system unlocked until someone tries to make an invalid pour. He said as soon as their is a detection of invalid flow the solenoids should be closed. I believe this will be harder to implement than having the solenoids normaly closed and assert them when a user approaches. However he said this will less lately to disturb the flow. We agreed to try the first method, and fall back on the second method if its not easy to implement. After our meeting I went to the lab and began working on a prelim Visio Layout drawing. I setup the scale so 1 grid square would be 1 mm. I then drew every part we had made a decision on to this scale. After that I began thinking about the orcad symbol for the rabbit. I remembered for the HC12 in 36w we had one on a disk. To figure this out I then began to look at older group projects on what they have done if they were using a rabbit. I think I am going to have to make a custom symbol in Orcad but I will have to talk to the TA. I also spent a few hours looking online for dual output dc to dc converters. All of the devices were as complicated or more as the MAXIM MAX786. I want to ask the TA's and professor about their experience with dual output power supplies.
WEEK 04 SUMMARY
Accomplishments: I finalized the Power Requirement and began a PCB layout in Visio. As a group we determined our menu system and a new block diagram. Weekly Work Total: 12.5 hours
Project Work Total: 35.5 hours
February 7 2006 (7 hours):
After speaking to Meyer and the TA's it appears I will be avoiding the MAX786. I began looking for simple 12-3.3 and 12-5 DC to DC Converters. I found a much simpler device from Linear Technologies this device called the LTC1256 has far less components and it can supply up to an amp of current. This chip also comes in 3.3V and 5V variants
LTC1265 Since we have our TCSP tomorrow I went to the lab to finalize the layout design. Matt was working on the packadging so we had to collarberate. We agreed to only control and monitor 4 kegs instead of the orginal 8. The general layout size will be 147.8mm by 108 mm. I reasoned that the control module should have the majority of the connectors at the end of the PCB. There will be two connectors mounted near the top of the board one for the LCD, and one for the dollar bill acceptor. The bottom of the board will feature the 12V Power connector. This is to minimize the high voltage high current traces on the PCB. The goal is to have all 12V Drive MOSFET near the bottom of the board. This way all the I/O going to a certain keg can be plugged and unplugged at will. The visio presentation document included for the TCSP is included here. Visio Layout
February 9 2006 (12 hours):
I discovered for the Packaging Spec I needed create a preliminary layout in Orcad. All of the parts we picked out had custom footprints. First I created the custom symbols for our Orcad Capture schematic. I then located symbols for every part we have ordered so far. I sampled some 2mm receptacles for our Rabbit Micro from Molex. I also located a 6 pin connector for each keg to connect to. This part is a Molex mx43045-0611. Here is a link to the data sheet Molex 6 pin Connector Male 43045 Along with its mating connector Molex 6 pin Connector Female 43045f Each keg will have these I/o: a 12V Drive signal from MOSFET to solenoid, a 12 V return, a 5 Volt signal to the Flowmeter, a 5 Volt Pulsed Signal, a 5 Volt Return, and a pin that loop back on the external connector to indicate to the micro that this keg is connected. The contactor and temperature probes can also use the same connector. I also went ahead and ordered the AED100US12 Power Supply from Newark. This power supply is rated for 8.3 amps while we calculated our total current draw for 8.25 amps. We are proposing to not let the solenoid and the dollar bill acceptor to operate at the same time. This will allow our maximum current draw to be only 5.25 amps, thus providing a safe margin. After I had made some good headway on the schematic I tried transfering it to Layout, but this failed since all of the parts didn't have footprints. I ended up going directly into layout and modified existing similiar parts to represent our micro and our rfid reader. I included headers for the lcd, rotary pulse generator, and dollar bill acceptor. This layout took quite some time but I think its a good first estimate for the preliminary. The new estimate is 105mm by 130mm.
PreLim Layout link I haven't considered any passive devices in this design but this provides some margin for growth. Once this layout was done I then wrote section 4 of the Design constraints Document.
WEEK 05 SUMMARY
Accomplishments: Completed PCB Preliminary Layout and began schematic, Also located connector for flow meters and solenoids. Purchased 100W AED100US12 Power Supply for Newark.
Weekly Work Total: 19 hours
Project Work Total: 54.5 hours
February 12 2006 (5.5 hours) :
Met with Ian in lab and together we picked out every connector, header, and receptacle we would need for our project. I gave up waiting for the samples to come in so I went ahead and bought the LTC12653.3 and LTC1265-5 directly from the company. We decieded to change the Solenoid and flow valve connector to a similiar product. This product has a through hole version. 6 pin connector Solenoid and Flow We also picked connectors for the temperature probes and contactor 2-pin Conector for temp probes and relay, We also bought the external mates and inserts for these connectors. Please see the attached Parts List for the mating Part Numbers. Finally we located and purchased 2 mm headers for the rabbit. 2mm headers The list of products I purchased today can be found here
Parts Order 2-12
February 14 2006 (4.5 hours):
Briefly talked to TA's about PCB footprint creation. I found a suitable connector for our External Power Supply. Its by Switchcraft with Newark PN:16F3602. I added this to the Newark parts list and submitted it. I then began working on the PCB schematic in Orcad. I learned how to hook up the Power Supplies from the LTC data sheet. Here are the two application circuits we are going to use. Power Supply application circuits I then uploaded all the data sheets, and updated the website to show them.
February 15 2006 (3 hours):
Learned how to hook up the RS-232 transcievers, along with the LCD based on the data sheets. Began going to Layout Tutorials in Orcad.
February 18 2006 (11 hours):
Learned how to create Custom Footprints in Orcad. Updated schematic to represent NPN Darlington with optocoupler. Then created ootprints for the Rabbit Headers, Molex 6 pin connectors, Molex 2 pin connectors, RS-232 chip.
WEEK 06 SUMMARY
Accomplishments: Purchased and received most of the Parts neeeded for the project. Made great progress on the schematic approx 60% done. Begain learning layout and created some custom footprints
Weekly Work Total: 23.5 hours
Project Work Total: 78 hours
February 19 2006 (13 hours):
Worked with Ian on the schematic, Discovered how the DC to DC converter worked and how to choose it parts. I then Ordered several parts from Mouser including 2mm connector inserts, a optocoupler with a built in NPN Darlington, Low ESR Capacitors which were needed for the PS design, size 1206 capacitors and resistors for the Power Supply. Also I ordered some extra NPN Darlington SMT chips in case the dual function opto-darlington chip will not work. I accidently deleted my custom footprint library so I had to recreate all of the footprints again. Luckily, since I understood the program I was much quicker at it. I also created custom footprints for the LCD header, the RPG header, the RFID chip, and the Low ESR Capacitors.
February 21 2006 (12 hours):
Started Layout but realized we were missing several key components. First our board needed additional headers around the micro for debugging. This will allow for ribbon cables from these headers to the PLD. In addition, a backup battery, reset switch, and audiotory transducer was included. I put all these new items in the schematic, and imported it into layout again. Ian worked on finding the parts, and ordering them, while I placed them in Orcad and created footprints. Finally, because we are considering a biometric sensor in our design, an extra added interface was included. Even if we can't use this device this header along with the RS-232 will allow for future expandability. When all the errors were gone in Design Rule Check, I began layout of the design. Becuase of time constraints I was only able to place the parts and I could not route any of the traces. I took screenshots of my progess so far and put them into Ian's slideshow. Below is the link to the slideshow
Week 7 Presentation
February 22 2006 (12 hours):
I Began routing traces for layout and I started with power and ground. I ran a 12V trace along the bottom of the board and another along with right side in the middle of the connector. I used the trace width calculator and choose 60mil as my trace size. As I was doing the layout I discovered some errors in the schematic so I had to re run the netlist several times. I also began writing my report.
February 23 2006 (15 hours):
I finished the 12V Power and Ground Traces, and then began routing 3.3V and 5V traces. I Routed 5V Power on the top edge and the Digital Ground on bottom directly underneath. To simply routing I tried to make the vertical traces on the bottom layer while the horizontal traces on top layer. Several times I rearraged pins on the micro and connector make routing easier. This reduced the number of vias in the design. At 11 am on pink day I had finished 80 percent of the traces but had 1000 errors. I Decided to take the 10% penalty after talking to Professor Meyer and Brian. I asked Brian to look at my design and he showed me how to fix some of my errors. I Decieded to get some sleep and have a better design to turn in.
February 24 2006 (14 hours):
Finished routing traces! I then began troubleshooting my errors. After several several hours I narrowed the DRC errors down to 26. Most of these errors are due to the tying of the 3.3V Gnd net with the 12V net. Segregating the digital ground and the analog ground this helped to reduce common mode interferance. However before leaving the board the two grounds must be tied together. This occured near the connector. After that I worked on removing all the partial rat nests. Using the silk screen layer I outlined all the partitons using the object tool. Also using the silk screen I labeled all the headers and connectors with text to indicate what needs to be connected. Finally I submitted the report right before noon on saturday. The report can be found here
PCB Layout Design
WEEK 07 SUMMARY
Accomplishments: Ian and I Finished Schematic. I Finished layout design and wrote PCB Report
Weekly Work Total: 66 hours
Project Work Total: 144 hours
February 27 2006 (5 hours):
Worked on creating slides for presentation on wed. Tried to minimize errors in layout. Fixed right angle and acute traces present. I think I have a good idea of what slides to show on wed.
February 28 2006 (13 hours):
I decided it would be a great idea to tie the grounds together at the connector since pins 2 and 3 of the connector are shorted. I am tying analog ground to pin 2 on the barrel connector and digital ground to pin 3 of the connector. Doing this eliminated all of DRC layout errors. I also re routed several of the traces in the power and ground rails to try and make them look cleaner. After that took screenshots of my pcb and added them to the power point presentation.Finally I printed 1:1 color copies of the top copper with silkscreen and the bottom copper with silkscreens. We also realized that we will need to move our headers to allow for the micro to properly fit. This will require some rework. The link to the mideterm presentation can be found here.
WEEK 08 SUMMARY
Accomplishments: Completed PCB with No DRC errors. Created layout slides and gave mid term presentation
Weekly Work Total: 18 hours
Project Work Total: 162 hours
March 6 2006 (8 hours):
Began rework of the PCB. First I moved the entire microprocessor headers down so that the micro would clear the rfid reader. Then I spaced the headers apart properly. I worked with Ian to locate a NPN transistor for the Solenoids. I suggesed we use the extra transistors I had bought. However we could not get them to work. Instead I suggested we use the NPN transistors used in 362 lab 9 TIP122. When we finally made all the necesssary changes to the schematic we imported our changes to layout. This unrouted about 40% of our traces. I taught Ian how to use layout and together we made some changes.
March 7 2006 (15 hours):
Asked Brian several layout questions to some of the issues I am having. I updated all the footprints so so they would not include silkscreen on the pads. I then updated the schematic with the new temperature probe configuration.Ian and I then traded off working on the PCB and testing components. There was some concern during the midterm review that 60 mils would not be sufficent to handle 4 Amps. However 4 Amps was the biggest size trace that could be fit between the connector pins and the thru hole. I decided to split the trace into traces. One trace on top would handle 2 Amps. While another trace on bottom would handel 2Amps. This should be sufficent for the amount of current. The new version of the PCB is much cleaner and has less components. Ian and I tested the 12VDC Power Supply with a solenoid, and I noticed when it was unplugged it seemed to chatter off and on. This probably won't be a problem since the device is always on.
March 8 2006 (12 hours):
I noticed that some of the footprints in our layout were incorrect. These include the XOR gate, and the PLD. These footprints required far less board space but their traces needed to be rerouted. When I got the routing to be 100% again. I helped Ian troubleshoot the Power Supply Circuit. In the process of debugging we found a few errors in our schematic and layout that needed to be corrected. Even when our circuit was correct with the datasheet we still had way too much current draw. We also placed all of the parts we had in hand on a 1:1 copy of our layout. Ian noticed the the 6 pin molex connector did not have the proper space between the pins and the thru hole. I made the necessary adjusments to the footprint. I noticed that no footprint for the RFID antenna had been created yet. So this was also created.
March 9 2006 (15 hours):
I asked Brian what the problem might be and he pointed to the long wires. Perhaps this is causing a inductance problem in the circuit. Ian began placing the parts on the 1:1 copy of the layout again while I fixed the right angle traces that matt had pointed out to me. Brian found several problems with our footprints including our Rabbit 2mm connectors. He helped us line up our Rabbit Connectors perfectly. In addition the footprints for our Tantalum capactiors were wrong. They did not have a sufficent pad size in order to solder them down on the board properly. After fixing all our footprints Brian gave us a check off for our Proof of Parts. Later in the evening Ian, Matt, Justin and I all met up to finalize the PCB. I adjusted all of the trace widths so that they were at least 12 mil. I adjusted the Power Traces to be at least 60 mil. Finally I changed the solenoid circuit trace width so that they would be large enough to handle the 1.2 Amps necessary. Matt and Justin also looked over the circuit for any trace width violations and for right angles. Around 3AM, we all began red lining the circuit to make sure that it was correct. Ian corrected some problems with the RFID. I went through the datasheet for the Power Supply ciruits and made the changes for all the layout suggestions. This involved moving many of the components and re routing them. Around 5 am on Friday I went through the procedure to submit the PCB. The Production Rules check found 12 show stoppers. These show stoppers were incorrectly defined Vias and incorrectly defined screw holes. Once these errors were fixed and I got the no Show stoppers message I submitted all the files necessary to Chuck. Later in the afternoon after recieving an email I submitted the Max file was well. The Final Top and Bottom copper layouts can be found below.
WEEK 09 SUMMARY
Accomplishments: Completed Proof of Parts. Completed Rework of PCB and submitted it for Production.
Weekly Work Total: 50 hours
Project Work Total: 212 hours
March 22 2006 (3 hours):
We recieved our PCB board today. After visually inspecting it, I began ohming out the board. Ian marked off on the 1:1 picture of the PCB as I went through it. There is a little concern with the size of a Via. This via is on the 12V Power Rail and its diameter is only 40 mil. When I finished ohming the board out, Ian soldered on the input Power connector. We connected the External Power supply and carefully monitoring the input voltage. I wanted to see how the input power would react to a load. To load the board we first used a 3 kOhm resistor. This behaved fine. Next we wanted to really load the board so we used one of our flow solenoids. When the input power was supplied the solenoid contacts opened. This process was repeated for 2 Solenoids and 3 Solednoids. We ran the max currrent that the via in question will ever see and there was no problem. Below is PCB that we recieved from the FAB house.
Real PCB Board
March 23 2006 (4.5 hours):
I helped Ian get the Power Supply circuit ready. One of the biggest challenges was trying to determine what the polarity band really meant. One team tried to convince Ian and I that all polarity bands are on the negative terminal and its industry standard. However, for our tantalum capacitors the polarity band indicates the positive terminal of the cap. This was verified using a capacitor, oscillscope, and a 5V power supply. We watched the 5V charge up and the voltage drop was positive. We then reversed the voltage and watched the voltage drop go negative on the scope. This confirmed our previous notion that polarity bands on the tantulum are on the positive side. After Ian had wired up the Power Supply circuit. We were ready to test. We used our 12V AC to DC converter and its connector to test. As soon as we connected the circuit the Power indication LED became extremely bright and an explosion occured near pin 12 of the Switching Power Supply. Ian took pictures of the circuit before and after the explosion on his camera. I wrote Linear Technologies, completely describing my circuit and asked for any troubleshooting advice. We did not unhook the circuit becuase we wanted to show it to the TA. The link below is a picture of the circuit after the explosion.
Burned Switching Power Supply
March 24 2006 (4.5 hours):
I spent today talking to the TA about our circuit that blew up. Within a few minutes of looking at it he found several problems. First we had been tying the LBO and LBI pins to ground. LBO should be left not connected, while LBI should be connected to 12V. This is low battery circuit and LBo is not used in this application. Next we wrongly tied the Power Supply pin 9 to Ground. There are three versions of this chip. A 5V, 3.3V, and Adjustable. However because of the manuafacturing process all the chips have the ability to be adjustable. Pin 9 is used as a voltage feedback pin for the switching power supply. If Pin 9 is tied to ground the device will continue to pull more and more current. This is exactly what cause the explosion. I also noitced that we were using a 3.3uH inductor instead of the recommended 33uH. Our inductor was not only the wrong value but it also had too low of a current rating. Eric Aasen from Team 12 has offered to me give some of his 47uH Power Inductors.
March 25 2006 (9 hours):
Ian and I cut the trace on pin 9, cut the trace on pin 4, and cut all references the Power Supply had to digital ground. These references were then fly wired to the analog ground at a single point near the Power Supply. We tested the resitors and the diode to make sure they were still in tact. The diode needed to be replace since its internal resistance was different than of the other identical sm chips that came in the same reel. 12V was then applied to the input of the board via the PS in order to limit current. The LED glowed bright blue. However, the output voltage was measuring out to be 5.8V. This was much higher than the allowed max .1V from the datasheet. Whats more when the power supply was further loaded the output voltage dropped severly. With 330k the voltage became 4.5 With two 330k in parrellel the output voltage became 3.3V We replaced all the components except the PS since it was already new. Later in the evening, when the LED was removed as a load the output voltage jumped to 11.8V. Very near the supply voltage. I was convinced this was a chip error and when it was replaced the circuit peformed perfectly. In addition the output voltage did not drindle a bit when it was loaded. We deceided to start our burn in and use our 12V In line Transformer. The Power Indication LED did not turn on when the 12V was applied. However, the output voltage of the switching power supply still measured to be 5.01V An LED was placed across the 5V line digital ground to indicate 5V working.
WEEK 10 SUMMARY
Accomplishments: Recieved PCB, ohmed the board, then populated the 5V Power Supply.
Weekly Work Total: 21 hours
Project Work Total: 233 hours
March 27 2006 (1 hours):
Ian informed me that we were missing a .1 Ohm Sensing Resistor. In order to get the 3.3 up and running we needed this resistor. I overnighted the .1 ohm resistor and a few extra tantalum caps since we didn't have any spares left.
March 28 2006 (3 hours):
Ian had populated the board except the .1Ohm Resistor. After checking it over. I put on the 0.1 Ohm and verified the 3.3V Volts worked. I then loaded the board one resisitor at a time until I got the power supply out of burst mode. When this was sucessful I cranked up the current limit on the power supply and verified that it didn't increase. Finally I tested the External Power Supply by plugging it into the connector. The board acted like it was receiving no power.
March 30 2006 (1.5 hours):
Asked Chuck to look over my External Power Supply issue. In the process of explaining problem I discovered a solution. Appparently the two grounds become seperated when the Input Jack is connected. I placed a fly wire between the the analog and digital ground terminals and power was restored. I left the board to burn in overnight.
WEEK 11 SUMMARY
Accomplishments: Fixed 3.3V Power Supply and Throughly tested it. Fixed External Power Issue with Power Supply.
Weekly Work Total: 5.5 hours
Project Work Total: 239.5 hours
April 3 2006 (3 hours):
I Spent the night learning and praticing crimping. I attempted to create a flowmeter and solenoid cable using our 43030-0008 inserts. When I was finished I tried to mate the connectors togethers. My wire to wire receptacle would not plug into the wire to board. After some reading at Molex I determined exactly why. The following website Good Crimps and ways to recognize them provided me ways to determine how not to crimp. In my crimping I made the wire lengths entirely too long, and the extended into the mating barrel. The male connector pin was then hitting this wire and instead of the socket.
April 4 2006 (2.5 hours):
Tonight I sucessfully made a solenoid and cable harness for one of the beverage lines. In the process I used all of the inserts I ordered. I then soldered on the flowmeter to the other end of the connector. I then proceeded to zip tie the entire bundle to keep it clean. We don't have the correct terminal lugs to mate onto the solenoid so I can't complete the harness. Below is a picture of the completed harness.
April 6 2006 (1 hours):
I placed an order at Mouser today. I ordered new inserts so I can make the rest of the beverage harnesses, 3 types Protection diodes which will prevent voltage transients on solenoids and contactors, and finally an eclosure for our compressor contactor. The contactor has open contactors and posses a dangerous risk even if its stored internally in the compressor contactor.
WEEK 12 SUMMARY
Accomplishments: Created Solenoid and flowmeter harness, and order remaining parts for project. Team soldered and got microprocessor to run heartbeat program.
Weekly Work Total: 6.5 hours
Project Work Total: 245.5 hours
April 10 2006 (3 hours):
Began contruction of compressor contactor harness, temperature probe harnesses, and currency acceptor power harness.
April 11 2006 (12 hours):
Started construction of LCD Harnesses and the RPG Harness. In the process of making them I realized we are using the wrong inserts. These inserts were male, while the contacts on the board were also male. I attempted to improvise. by cutting the male portions of these inserts. When testing these harness they appeared to be very finicky. I think we will need to order the correct inserts. After taking a break I stayed up the entire night working on the reliability and safety analysis for wednesdays presentation. I divided the schematic into 8 sections. For each section I listed all the possibilities of failure. For each failure mode, I listed what might be the cause of failure. Below is a link to the presentation.
April 13 2006 (8 hours):
I spent the evening working on the Reliability Report. I choose the Compressor Contactor (MGM Power Relay), the Switching Power Supplies (LTC-1265) the Solenoid valves, and the Power MOSFETs as the parts parts to calculate the number of failure in hours and the mean time to failure (MTTF). The contactor, and solenoid were choosen because of there high frequency of use and expoure to elevated temperatures. The switching power supplies, and MOSFET's were choosen because of there high current ratings and frequency of use. I determined the most dangerous failure would be one in which the compressor failed closed. In this failure mode the compressor could overheat and lead to a fire of the entire system. In addition I created three different criticallity of failures. A High criticality would result in damage to user and system. A medium criticality would result in loss of major functionality but would result in no damage to user. Finally, a low criticality failure would result in only slight or no loss of functionality of the system. The completed report can be found below.
Reliabiity and Saftey Analysis
April 14 2006 (3 hours):
I recieved my Mouser Order and constructed two other Solenoid and Flowmeter Harnesses. Matt had bought the terminal lugs so I could build the complete harnesses. I choose the orange-white wire for the solenoids, White for the LED Return and the 5V Power to the flowmeter, blue flowmeter pulse, and black for digital ground. All three harnesses can be found below
Reliabiity and Saftey Analysis
April 15 2006 (2.5 hours):
I came in Saturaday because Ian bought the correct inserts for the LCD and RPG harnesses. I recreated these cables so he could begin creating the LCD menu. Shown below are these harnesses
Reliabiity and Saftey Analysis
WEEK 13 SUMMARY
Accomplishments: Created almost all wire harnesses for system and wrote Reliabilty Analysis.
Weekly Work Total: 28.5 hours
Project Work Total: 274 hours
April 18 2006 (2.5 hours):
I fixed the problem on the RPG Harness, I had the RS-232 transmit and recieve signals backwards. Also, Justin, Matt, and I brought our freezer into lab.
April 20 2006 (3 hours):
I created the Biometric Harness for the Fingerprint Reader. These signals intially go to a controller and then go to the thumb print reader.
April 21 2006 (4.5 hours):
I began modifying the compressor for our temperature control. I first cut the line in between the temperature controller and the compressor. Next I feed the cotactor control harness through the fridge up to the top of the kegerator. Matt told me he wanted another power cord for the freezer becuase his had become damaged. I went upstatirs to the EE shop and convinced them to give me some of there spare electrical power cords. When I was cutting the power cord I made the mistake of not marking the polarities of the wires. I determined that I could look at the HKN fridge since it was identical to determine the polarity. However it was after five and I could not get into lounge.
April 22 2006 (8 hours):
Matt, Justin, and I brought in the rootbeer keg that we purchased from village bottle shop. Matt let me into the HKN lounge so I could look at the freezer. After correctly determining polarity I began Soldering the new Power Cord for the freezer. In addition, I soldered a 18 gauge Power Supply cord at this same place. Please see the picture below. This cord which was part of a computer cord will be used to power the 12V In-Line Transformer and eventually our board. After careful inspection we plugged the freezer and tried controlling the freezer with our contactor. It worked perfectly, we then tapped the keg, and served rootbeer!
WEEK 14 SUMMARY
Accomplishments: Modified freezer for Compressor Contactor, created biometric harness. Supply.
Weekly Work Total: 18 hours
Project Work Total: 292 hours