2020-12-15, 05:47 PM
(2020-12-15, 02:24 PM)Kris Wrote: Thanks for posting the schematic again. I have seen it in the thread before but did not understand at the time. You have wired it up exactly the way I did with mine, with the little difference of how I drive my clutch and shunt. Don't worry that you do not have the original NECO stuff inside of the box. You really just need the rudder potentiometer with the end switches (although you can get away without them) and the leads to the coils. I have this big mess of wires that make it look complicated, but just so I can switch back to the NECO CU.
With the pololu, you have to use the RC pwm mode that drives the pin at 50% duty cycle for no motor movement. You could try to wake up the part of the motorino code that drives the low side of the Hbridge.
A lazier option would be to order an IBT2 online for 10 euros and try it the way I did on mine, using the H-bridge mode. You will save a bit more than half of the idling current (when the motor does not move but the clutch is engaged). If we ever get the clutch to be driven with PWM, we will massage the idling current down to less than a quarter. My NECO CU takes about 60 watts on idling. Now with pypilot it idles on less than 20 watts, and more savings are to be expected with the clutch.
Hi Kris,
I´m happy with the pololu as I can test the drive and the end switches, start/stop characteristics and I think also break and stall/power settings with the pololu setup program on my laptopp with a usb cable. This way it was also easy to identify wich cables were wich coil.
The pypilot with the arduino and the imu (I use an arduino mini pro) are sitting in a separate watertight box and only 3 wires (RC, Clutch and GND) are going to the Neco drive, were the pololu is. So this configuration makes it verry ease to search for foults. I have an extra arduino pro mini with an modified motor.ino and 3 led (clutch,stb,port) exchangeing and testing. As well I have all componets in spare, just in case. (I do a lot single haded and don´t want to be without autopilot.)
For the PWM clutch, I would go for a second arduino pro mini (1,8x3,3mm and less then 2€ the clone) programmed to drive the clutch.
Signal in would be the Pin 8 from the other arduino and out the PWM 100% and after an delay the low to hold the clutch. This would be a relatively simple programm and you don´t need to t go into Sean´s motor.ino witch is as far as I understand using interupts and internal timers for time critical operations.
As I stated in some post erlier I have a direct wire to interupt the clutch ... for emergency if the Pypilot starts getting mad ... at the control panel in the cocpit. I would make this into an 3 position switch, off-auto-on. so AUTO would be the pwm driven arduino clutch control, ON would be direct power to the clutch and OFF the erlier on described ermergency cut off.
So far I don´t need the above modification but I would do for an atlantic crossing or so, the estimated saving would be 10W/h equal to 240W/h a day, do you think that is correct ?
One question, what transistor do you use for driving the clutch from the arduino? I think that my SSR-Mosfet is a little overkill ....
Save sailing
Andreas