Replacement for the Bigfoot control unit

Shortcomings of the Bigfoot control unit:

– Slow grounding of legs – only one at a time
– Automatic grounding of legs only as part of autolevel, not separate function
– Left to right position not programmable
– Pumps don’t stop when leg is up until last one is up
– Front to rear angle always 0 in dedicated display mode – works with auto level.
– System can be deadlocked and will not move when angle is too high – no manual override
– System stops when battery is low in retract all mode, does not use single legs for less battery drain
– No manual control for each leg – Bigfoot has done that on purpose to avoid chassis twisting
– Autolevel is slow, long pauses between operations
– Calibration requires all legs to be up and then brought down to level

My requirements:

– Grounding front legs as separate function
– Moving more than one leg at a time when grounding two or 4 legs
– Calibrating left to right position
– Stopping each leg when limiter switch opens
– Display angle at all times – left/right – front/rear at the same time
– Manual control for each leg
– Twist protection with manual override
– Battery monitor with power safe mode – running single legs when battery low until minimum
– Faster auto level
– Calibration to 0 at any time
– Unhitch function with two preprogrammed angles
– Hitch function will return to unhitch height with 2 modes – level or unhitch angle
– Bluetooth app for phone

Komponents:

Display/Keypad Panel and control unit
Relais driver unit

Parts for keypad panel:

Keypad 4×4 or 4×5 buttons $3.00
Arduino Uno R3 $5.00
Can Bus Shield $13.00
Bluetooth module $6.00
2 Line character Display $12
Box 120x120x90 $13.00
4 Pole waterproof connector x 2 $7.60 -(1) power and Can bus – (2) Limiter switch input
Gyro module $5.00
1 9 pin waterproof connector $6.00 – control lines for leg solinoids 8 + 1 to driver unit

Total Cost: $70.60 Quantity required: 1

Parts for driver unit:

2 4 Relais boards $18.00
1 9 pin waterproof connector $6.00 – control lines for leg solinoids 8 + 1 from keypad module
2 4 pin waterproof connector $5.00 – solinoid driver for 2 legs (up/down) – front and rear
1 3 pin waterproof connector $2.00 – power supply for solinoid driver
Box 120x120x90 $13.00

Total Cost: $44.00 Quantity required: 1

Connection cable between control unit and driver unit – 9 core
Y-cables to split solinoid interface cables and limiter switch cables 5core each
CAN bus drop cable to Can bus distribution box

Elementary functions to implement:

– Front left leg up with stop when limiter switch opens
– Front right leg up with stop when limiter switch opens
– Rear left leg up with stop when limiter switch opens
– Rear right leg up with stop when limiter switch opens
– Front legs up with individual stop when limiter switch opens
– Rear legs up with individual stop when limiter switch opens
– All legs up with individual stop when limiter switch opens
– All legs up with individual stop when limiter switch opens and battery safe mode

– Grounding left front leg
– Grounding right front leg
– Grounding left rear leg
– Grounding right rear leg
– Grounding front legs
– Grounding rear legs
– Grounding all legs
– Extend all 4 legs simultaneously

– Identify front to rear
– Identify left to right
– Set zero point
– Auto level

– Set unhitch default 1
– Set unhitch default 2

– Lift to unhitch default 1
– Lift to unhitch default 2
– Set current unhitch level
– Lift to last unhitch level at original angle left/right
– Lift to last unhitch level at 0 angle left/right

– Auto level from unhitch position

– Reduce to minimal height
– Lift to default height

– Measure front to rear angle
– Measure left to right angle
– Display front to rear angle
– Display left to right angle

– Display battery voltage

– Set max allowed left to right angle
– Set max allowed front to rear angle

– Display twist warning
– Allow max angle override

level_box_front

Actual Implementation

Implemented in one box. There was no need to make two separate units because the accelerometer is precise enough to be mounted at any point. Saved the effort of linking display and processor. For my own application this is sufficient and it is not planned to commercialise the unit. Another consequence of integration into one box is the fact that no water proof connectors were required because the box will be mounted inside a baggage section and is protected from the elements.

level_box_inside

Parts used

Keypad 4×4 buttons $3.00
Arduino Uno R3 $5.00
Can Bus Shield $13.00
2 Line character Display $12
Box 150x120x90 $13.00
Gyro module $5.00
2 4 Relais boards $18.00
2 DC-DC power supllies $2

1 16 DIO IO Expander shield $9.50
1 Screw shield $8
1 Temperature sensor $1
1 Voltage reference $1.20
1 Opto DC In board $8.95
1 I2C Hub $4.95
6 panel connectors $2.40
Cables & internal connectors $3.00

Total: $108