-
Notifications
You must be signed in to change notification settings - Fork 0
X13 Solenoid
IMAGE OF PCB, potentially including its place on the relevant ROV
| PCB Summary | |
|---|---|
| Vehicle | {X13, ROV Triton, with link} |
| Contributors | Erin Park |
| Predecessors | X12-Solenoid |
| Success? | Yes, with a tiny flaw |
Architecture Link
SID Link
REPO Link
- Drive 6 solenoids using a BJT array and input signals from STM (controller)
- Receive commands from raspi using CAN
- Bricks communication using PMBUS using pins ALERT1 and 2, DATA, C2_1, C2_2 * C2 1 and 2 turn on/off the power bricks * Clk exists for being clock
- Backplane * via Samtec TMM * Low profile TMM connector - long 11x2 thingy carries all of the power and logic on the same connector
What priorities did you have in your design? What design considerations did you have? What methodologies did you follow? (routing a differential pair, keeping something separate for isolation, etc)
- Moved solenoid board from solenoid enclosure to backplane - this allows us to not have a separate 12-3.3v conversion and have backplane take care of the solenoid connections
- Has IO for controlling bricks - power on etc
- SMOL (we like smol board)
- Just made it as small as possible
- Nucleo data sheet
- Nucleo schematic (useful for nRST and oscillator circuit) Download the zip schematic pack or view it here
-
Transistor array
- This datasheet is very useful
- Functional diagram shows everything - stm output -> bjt input -> bjt output goes out to backplane
- Flyback diode big pog prevents leftover current from messing stuff up PICTURE
- 3.3v: smol
- 12v: transistor array can drive like up to 250 mA each but the solenoids we’re using only need around 30. So worst case scenario 30*6 mA draw
- Datasheet Very Nice PICTURE
Why did you pick certain components for your board? (If you don't know the answer/were told, now is a great time to ask)
- Connectors: ones we used were low-profile, keeps it smol in 3d too
- Include links to components for future reference
- https://www.diodes.com/assets/Datasheets/ULN2003V12.pdf
- Initially was placed on the underside of the backplane which was very meh because the reset switch and LEDs were backwards - make sure your backplane person puts their solenoid space on the top layer
- Do ALL component placement before any wiring - u will have ragrats if u don't
- Also very challenging and time consuming to make space for even 1 smd because of how cramped it is
- Mechanical? What’s that
- Have fun playing component tetris, fun tho
- SWDIO and SWCLK should be swapped in the STM pinout to make it easier for
- Fixed on eagle
- Decoupling capacitors for STM should be as close to the STM as possible, preferably "before" the stm pad
- Ground plane is very chopped up, this is fine as long as there are multiple paths to ground but try to keep it intact and/or continuous where ground pads are
- Do more component placement before wiring
- Board is very cramped in some places which is fine but was hard
trace width calculator Use this for trace widths but if a trace can be thicker for no space constraints, do that Make sure transistor array can output enough for solenoids if solenoids change.
Search keywords.
The Solenoid board is responsible for driving the various solenoids for the ROV. It interfaces with the Backplane, receiving power and IO in. It then outputs either 0v or 12v to control the state of the solenoid. A major change that was made from the previous year is that the solenoid board was moved from the solenoid enclosure to inside the powerbox. With this change, the solenoid board is significantly less likely to be damaged in the case of a solenoid enclosure leak.
PICTURES
Tools
Enclosures
Frames
Other
ROS