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Ardumower arduino mega shield

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walter

New member
Hi

As already discused with Alex,Markus and Sven I start this new topic

Enclosed you will find a schematic of the actual ardumower setup as far i could find out (please correct me)

I used labels in the schematic so that i can easily change pins to simplify the PCB layout later

First i will make a simple shield for my needs (RL500) and little by little at sensors

I'm thinking of making the shield a bit bigger than the arduino, so that ground and +5V will be the outside of the board

All sensors/switches/modules will have headers on the board with all signals,+5v and ground

Integrated on the board the HC05 bluetooth module, MC33926 module,DC DC converter (thanks Marksu) buzzer,button, and led
etc...

my goal is to make a single side PCB that you can build yourself the "good old way"

the following will be external of the board:


- The perimeter sensor and amplifier
- Fuse on battery
- Schottky diode for charging
- charge current sensor
- drive motor H-bridge (except if you use the dual MC33926 module)
- mowmotor H-bridge
- drive motor currentsensor (except if you use the dual MC33926 module)
- mowmotor current sensor

Have a look at the schematic and correct me please

Walter

ardumowershieldSchematic.pdf
 
Hi Walter,

Looks good. Why fuse holder and schottky diode are out of the board ?
Rest looks very good.
Looking forward for first PCB layout.

Alex
 
@Walter: Looks good! I wonder if you could make available the schematic project files, so we may add the remaining components for a all-on-one PCB... :)
 
AlexanderG schrieb:
@Walter: Looks good! I wonder if you could make available the schematic project files, so we may add the remaining components for a all-on-one PCB... :)
Zum Vergrößern anklicken....


Me also :)

Alex
 
Zuletzt bearbeitet von einem Moderator:
Hi Ardumowers

Yesterday i started to draw the PCB as I did NOT or got little feedback on errors on the schematic

The PCB is for 75% ready (and I can tell you it was late yesterday =) =)

I enclose the new schematic, i changed some pins to make the PCB layout more easy

I hope i did not make any mistake on PWM/ADC/UART and normal pins (could someone double check this ?)

The PCB is a standard eurocard 10x16cm, single sided but with some wire vias ofcourse
NO AUTOROUTERS , manual routing and normal track width so you can make it yourself !!! (DIY)

@Alex or was it Sven: 2 x dual MC33296 are implemented, also all features are on headers

further i will Look for some space to put the schotky diode and connection terminal
but i dont see a problem to wire this outside togheter with a fuse


PS: PRoject files will be donated to the Ardumower team as the PCB is finished (i order not to make a pcb in parallel with the same people

More to come !

Walter
Attachment: https://forum.ardumower.de/data/media/kunena/attachments/1340/ardumowershieldSchematic.pdf/
 
Zuletzt bearbeitet von einem Moderator:
Hi Walter,

I will try to check you schematic, but are you sure that there must be 2 x dual MC33296 ?? Why not only one ?

Alex
 
@Alex: The first dual is for the left and right wheel motors - the second dual is for the mower motor (both H-bridges working in parallel for maximum current).
 
ok,

and is +5V necessary on the bumper connector ? But why not...... can be used for other function.

Alex
 
@alex some asked to add a second one for mower motors
But all signals are in parallel on a header
So you can leave one out and use a fet switch
 
No normally not, but all headers has +5v and gnd

If you ever have to drive an optocoupler or whatever
It will be available
 
@Walter: I also successfully tested the MC driver in parallel configuration today - direction can be fix (GND) if this saves space on the board.
 
@Walter: we found out that we need to change pin4 into pin5 so we change the PWM frequency using one common timer for all motor pins, so:

#define pinMotorRightPWM 3 // M2_IN1 right motor PWM pin
#define pinMotorLeftPWM 5 // M1_IN1 left motor PWM pin
#define pinMotorMowPWM 2 // M1_IN1 mower motor PWM pin
 
@Walter: one important thing about the battery: I think it's important to make the circuit robust against wrong battery wiring (+/-), so I suggest this circuit:


Code: 
BAT(+)----o---fuse 3.15A/slow-----+-----------o
                                 ----
                                  /   diode (min.5A)
                                 /--
                                  |                                  
BAT(-)----o-----------------------+-----------o


The idea is that if someone wrongly connects battery, the diode will open, and then fuse will break (due to the high current)...

The remaining circuit will survive (this wil save money :)...)

The diode (A) should always be larger than the fuse (A), so the diode will not break in case of wrong wiring.
 
AlexanderG schrieb:
@Walter: we found out that we need to change pin4 into pin5 so we change the PWM frequency using one common timer for all motor pins, so:

#define pinMotorRightPWM 3 // M2_IN1 right motor PWM pin
#define pinMotorLeftPWM 5 // M1_IN1 left motor PWM pin
#define pinMotorMowPWM 2 // M1_IN1 mower motor PWM pin
Zum Vergrößern anklicken....

Is this change already implemented in the sw? Why I am asking is,if I can use this shield with current hw or I must rework somethink?

Alex
 
Zuletzt bearbeitet von einem Moderator:
@Alex: The latest development version already contains this pin change. The shield will always work as you can quickly change the pin in the software. However it is recommended to change the pin so future software versions can change PWM frequency (not required but nice-to-have)...

The latest development version can always be found here (Source->Checkout / Browse):
https://code.google.com/p/ardumower/
 
Thanks
I want only be sure that this shield will be universal as much as possible, because I see that there is running development like no nano board for perimeter,but this is still development and would be fine that this shield will be able handle as much variants as possible.

Alex
 
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