mikey

So, I took this for a drive on the weekend. Still need to put a bunch of interior trim in, and go for a cert. It's dropped a cylinder somewhere in the last 5 months, hopefully that wont be a hard fix.

I've been working away but it's not very interesting stuff. I've cleaned up all my wiring and mounted the fuse box and rebuilt all the heater stuffs. Dash is back in. The tacho is being a total vag so I'm ditching that stupid circuit and replacing it with a stepper motor at some point when I care enough. Replaced the rubber bits on the quarter windows. If things go really well I might be driving this on the weekend. There's still lots of things to do; some upholstery, put all the windows back in, door lock actuators, all the interior panels, indicators, seats & belts. Mostly a million little thingys.

Good shit brother all looking legit. Brings back memories. Will be the fucken bizzo when all low and that. Yay!

Yeah man, those guys do a bloody through job and are great to deal with. After they painted the shell they weren't happy with the prep in a couple of areas so sanded it back and did it again, it had not effect on the price. Cant big them up enough!

Yep, I'm pretty damn happy with it

Yep, more than I expected too. Given the amount of work they did, and the quality, I thought the price was totally reasonable.

OH WOULD YOU JUST STOP IT!! Stokedness is on MAXIMUM.

Yeah, GT Refinishers have done such a damn good job, and a bloody nice fellas to boot. I'm a wee bit nervous of the final bill myself, oh well.

Golly gosh! Shit's looking dope.

So excited shit's happening with this!

Oh mean! I actually just found these little suckers on ebay a couple of days ago. I've ordered one, hopefully it doesn't take too long to show up, they look perfect. Glad to hear I'm not the only one who's done something like this. I pulled apart the speedo tonight and removed all the mechanical cable input. I mounted a stepper motor on the odometer and it spins the odometer and trip meter perfectly. So all I have to do is wait for the speedo stepper and mount that. Which reminds me, I have to drop off your other motor and ESC I have here. Thanks for letting me play with them, even though I wont be using them it was all part of the process of getting to this point. When suits? Whats your addr?

I think I'm gonna change tack. This BLDC thing seems quite tricky. So what is probably easier is driving the needle and the odo with little stepper motors I just pinched from old CDROM's at work: I even have a proof of concept we made whilst pissing around:

Deffo black! So stoked with how it came out. Just can't wait to start putting it back together!

Yep, you got it. Dashboard Restos, Steve is a really nice chap. Real good to deal with.

Dashboard is recovered and looking super! Before: After: Latest pic of the car, 50% in primer, many new patches, no filler yet.

Awesome work!

YEAHYA! Awesome.

Yeah, if we can get an ESC to run slow enough and at fixed speeds then I'll go that way. But at the moment it's looking easier to rip the guts out of the speedo and hook a stepper up to the needle. I can hook another stepper up to the odometer. Just seems easier to me now? I'm reaching the limit of my know-how with driving the BLDC from the PIC I think, even with the L239D motor driver.

It must be possible to get ESC's that work with precise speeds, otherwise RC helicopters would be shit. Edit: Yeah, looks like a lot of ESC's allow you program them in constant speed mode. Which is probably what I need to do. Ned, any idea what model ESC this is? Or of that open source ESC code supports constant speed mode?

Yeah, maybe, it's worth a shot. I'll try and give it a go tomorrow.

The ESC does some sensing of the supply voltage and beeps warnings when it's too low. Not sure where that cut off is but it wont run as low as 5v. I don't have a proper adjustable power supply unfortunately. The motor control chip I have has all the H-bridges I need, but I'm just not sure if PWM modulating the motor in open loop will work and it sounds like a truck load of work.... Modifying the AVR code would be great. But I'm just a little unsure if it'll work... If we slow down the motor too much I'm guessing it wont induce enough current in the unpowered coil to sense the correct timing and work in closed loop. Open loop seems to make more sense to me than closed loop anyhow, as we want to run at a set speed so we dont care about the optimal timing. However to avoid overstepping I have to PWM the coils as well as adjust the timing I switch them on and off. And at this point my brain hurts....

The same problem being non-constant speed when under load?

Hey Ned, what make/model is that ESC? There's no marking on it. Some dont go below 30% duty, I wonder if this is one of them.

To achieve slow enough speeds? I can drive the motor with the motor driver chip I was using for the stepper I had before. If I dont wanna run full speed though I have to PWM each coil as I go. Probably not a major problem. There's even open source ESC code for PIC's I can use. But, would running a lower KV motor be enough to slow things down without all the bother? One issue with the ESC is I _think_ they detect speed by reading the unused coil while they charge the other two. So that explains why it's susceptible to load but doesn't end out skipping steps. This is all just a theory / what I've pieced together today by reading / I know fuck all about these motors.

This is a video of it running at the slowest speed the controller will run at: There's a couple of problems, that speed is far to fast, but also depending on how much load I put on the motor the speed jumps around quiet a bit. During that vid I'm changing how much weight I put on the motor which has a big effect on speed. Time will tell if this will be an issue or not. I need to organise a proper connection between the motor and speedo and see how it goes.