Centre Console Meeting Notes (Fall 2024) [MSXV]
Friday Oct 4
Deliverables:
Finish specing out cam
The camera that was suggested was okay, but the rear lines obstruct view and can’t be toggled off
Again:
CVBS Cam
Investigate solutions to obscured display view
The display is hard to see when the canopy is closed
Go to car and find out where the displays should be moved to on the board to fix this issue
Rough Notes:
Final Results/Comments:
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Spec out new 7 segment display
Higher Lumen Value
OR change resistor value to a lower value
Also ensure all displays are RED
Current 7 Seg displays
Green 3 Digit:
Other 2 Red 3 Digit
Currently FOR BOTH:
39 mA
2.2V Forward Voltage
5V Supply
140 mA Peak Forward Current
Notes from Jun:
Seems that the 3 Digit Green has a way higher MCD value than the Red MCD value (8.6 mcd to 0.65 mcd)
Make sure they have the same mcd value
For speccing new display:
Green 3 Digit:
Package: 28-DIP Module (0.600", 15.24mm), 12 Leads
Higher than 8.6mcd (look at millicandela value)
RED!!!!
Red 3 Digit:
Package: 16-DIP
Higher than 0.65mcd (look at millicandela value)
For new resistor values:
Use this:
https://www.digikey.ca/en/resources/conversion-calculators/conversion-calculator-led-series-resistor
2.2V Forward Voltage
5V Supply
90 mA is Peak Forward Current FOR RED, ensure its lower than this
Less than 70mA
140 mA is Peak Forward Current FOR GREEN, ensure its lower than this
FIND RESISTORS THAT WE HAVE RIGHT NOW FOR CHEAPEST OPTION
(5V< Voltage rating)
0603 Package size
Figure out what is a cheaper fix!
Results Large 7 segment:
Smaller 7 segments: Smaller: Best bet, although this one is only 0.15 mcd higher than the current displays in use. https://www.mouser.ca/ProductDetail/Lite-On/LTC-4624P?qs=WxFF5lh7QM1T0JD0JNkh9w%3D%3D
Larger: (need to make new footprint and reroute for this one, 28 leads instead of 12) https://www.digikey.ca/en/products/detail/lumex-opto-components-inc/LDT-C514RI/252629
12 leads, same size, smaller mcd (5.8mcd) https://www.digikey.ca/en/products/detail/kingbright/BC56-12EWA/3084334
Cost for new display: $9.18 before tax/shipping for one of the new larger displays
Cost for new resistors:
Format: 0603_1608 Current resistors (for both): 68 ohms For highsafe current for red (70mA): 38.5 ohms (40.2 available/ 64 mA) 84 mA: 33 ohm (33 available) Nothing in stocks between 40.2 and 61.9 For green (to lower brightness): 82, 85, 75 ohms in stock (only enough of 82 ohms)
No purchase needed for resistors if using available resistors above
Conclusions:
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Final stuff
Figure out meeting time/day to officially put
After Tuesday Oct 11 hardware meeting 4PM
(ask Aden about turn signal stalk functionality, where to start)
“Homework”:
Read this, and the other pages within it to learn more about the board (Will probably give a brief design overview with annotations on the board next week)
https://uwmidsun.atlassian.net/wiki/spaces/ELEC/pages/846364897/Center+Console+MS+14
Review the PCB layout here, start to ideate the placement of everything
Notes:
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Thursday Oct 10
Recap
Reviewed centre console schematics and PCB Layout you can look at the slides here: https://docs.google.com/presentation/d/1Xj0OHcUJO4kSlH0nggiOzdxVnmcHF2jc0GeiQRAbxBM/edit?usp=sharing
Created altium component for 7 seg display we specced out
Started up a new Rev for the board, and placed mounting holes, connectors, controllerboard, 7 segments on the board can see it here: https://university-of-waterloo-solar-car-team.365.altium.com/designs/7465A08B-3ADD-4697-863E-57BDD51FBE91?activeDocumentId=Block_Diagram.SchDoc&variant=[No+Variations]&activeView=SCH&location=[1,95.76,31.99,41.41]#design
Decided to let firmware PWM the mosfets for each display to adjust the brightness and have a potentiometer connected to the controller board for control.
Next Steps
Figure out what parts of the schematic you want to layout
*Buttons, buck converter/12v input (@Ben Holland) *Displays (@Khalil Ramzi) *Cruise Control ( @Red McMahon-Thibeault) *Hall sensor ( @Jenna Wan, @Ashley Moon)can get two people on this) (Dont start routing yet! Figure out layout before routing!)
Spec out a potentiometer for brightness display and put it on the schematic
Harnessing (will be more for in person meetings/after midterms)
Thursday Oct 31
Recap