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Lotussuper7 last won the day on July 7

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  1. You mentioned you could drive a standard hobby servo. On that ground, could you just control a Radio control brushless/brushed speed controller and spin a brushless/brushed motor instead of the stepper, I have loads of rc gear. A brushed motor may be better as they usually have better low speed capabilities. You can also no doubt get pwm driven speed controllers for Arduino etc. Will have a look around.
  2. Hmm, will have to think this one over. Thanks! Will keep the post updated as things progress.
  3. That's just what I was investigating. Seems most can support around 1500 rpm with full stepping. Dependent on the driven voltage and load. The gauge require very little torque to operate, it will be the speed that may be an issue, may need to incorporate a couple of gears (or belt) into the 3d printed design. Do you know off hand how many pulses (hz) the Fury x can supply on the aux outputs? Standard steppers on full step use 200 pulses per rev, so at say 2000 turns, that would be 2000x200 = 400,000 pulses at 200kph. Maybe less obviously if gearing is involved.
  4. Thanks for your reply. I realise how a stepper motor works as I have many years working with 3d printers. I dont think we are quite on the same page. The speedometer I want to drive does not have absolute positioning, and I dont want to drive it do defined positions. It works by spinning a magnet inside and dragging the needle around further the faster the input spins. To increase the speed showing on the speedo simply requires spinning the input faster or slower. No need for absolute position, only number of pulses per sec need to change relative to the cars speed. This is a fixed ratio driven from the gearbox output. I'm not looking for absolute precision here, just a way to have the odometer stay working, and have 'close enough' speed showing. I have the digital wheel speed available, and can display this on my displaylink screen also.
  5. Thanks for the reply, so that would probably be the way to go then, use an external stepper driver and drive it off an aux channel using the speedometer feature, rather than drive the stepper from the ecu. I only suggested driving it from the ecu for simplicity, as I dont use a idle stepper, I figured this might have been a simple option.
  6. Just to clarify what I was trying to achieve. My idea was to still use the cable drive input of the speedometer, and replicate the flex cable spinning the input with the stepper, I wasn't going to go as far as interfacing directly to the needle and driving to a specified angle etc.. no cool needle test sweep unfortunately. It just needs to speed up the stepper as wheel speed increases, with a tuning offset. I was thinking this could just be achieved with a math channel? The stepper driver was going to be left in full step mode to get the lowest frequency drive signal, and fastest rpm of the stepper, the cable spins relatively fast.
  7. My original plan was to use a a4988 stepper driver to drive the stepper motor. This requires a high pulse to drive the stepper one step, There would be no need to have a home position as to stop the speedometer counting only requires the stepper to stop turning, not like controlling a air bleed that needs to reverse to open/close a valve. Can the ecu generate a frequency relative to the speed frequency generated by the wheel speed sensor?
  8. After much messing around trying too get my cable driven speedometer working properly, I have decided to try and add a stepper motor to drive the speedometer directly ( and get rid of the stupid cable , lol). I'm going to 3d print a bracket to mount the motor on the rear of the gauge , and come up with some way of connecting them (I want to keep the original Smiths gauge as it has the cars odometer). I have got wheel speed working well, so I guess my question is, Can I drive a standard Nema (14/17) stepper directly using the Aux outs, or should I add an external stepper driver and just use one digital out to drive the driver hi/low etc. Is there a benefit to either way ecu wise? Any thoughts welcome. Cheers
  9. I have a display link running on a g4x. It works, but in my opinion was never realy polished. Some functions are very limited, and other streamed values dont show properly. With a bit of fiddling in the Can menu you can get most things working properly. Ie. I had temps showing incorrectly, decimal places in the wrong place etc. Hopefully you have some luck with it, I remember the amount I payed for it, but would like to forget. As for the knock block, that plug looks like a pc power supply connector.
  10. Just a small one, Confirm log delete in ecu logs. If you accidentally click on delete all logs, there is no conformation dialog.
  11. Exactly what happens. And as I said, I read another's post that said the same (unless that was you, lol). I have a standalone g4x fury.
  12. I didnt really think it would be related. When it happens, the ecu itself just doesn't power up at all. Im 99.9% sure that its getting power when this fault occurs, as I have tested the VCC of the ecu when in that state . I have read somewhere else in the forum another person having the same issue, (probably where I should have mentioned this). The ecu has never quit once powered up. And never failed to start when the laptop hasn't just been connected (its mostly connected recently as I have been tinkering) . Its not a big deal, as it only happens every so often, just an observation. I will try and find the post on that users problem, if I can find it. As for the connection issues, not sure about that one. I have tried different Baud rates, different com ports, manual port selection, and other port related settings, however, still have not found any that will reliably hold the connection when downloading logs. Running in slow mode seems to work, however, goes slower than real time, and is a real pain, and that's only for small logs, I cant Imagine how long it would take for big logs. When running out of slow mode, I can sometimes get the logs to download quick and easy, but its hit and miss. So, in a way I think you are on the right track with it being a relay, but its not (at least in my case) the fuel pump relay, My symptoms would indicate an internal relay (circuit) in the ecu not turning on. I'm not saying that is definitely the problem, however, the symptoms would match. The fuel pump in my case simply does not turn on, because the ecu doesn't come on. As I say, it only happens infrequently, and turning the ignition on and off has always seen it come alive on the second go.
  13. Further update to this topic. After a few very frustrating days trying to figure out what was going on I think I finally have this sorted. I have found out that the cheap sensor I purchased was rubbish, the armature that spins inside was not captured in the housing properly and was allowed to move in and out, this made the readings from the sensor very erratic. The magnets were also very weak, so I think that was why I got more erratic readings when using another hall sensor temporarily taped to the side. I have done some ' modifications' to the sensor, including drilling holes in the armature and fitting some new magnets, replacing the bushings with bearings, including thrust bearings and gutting the electronics and replacing them with a new barrel type hall sensor. Now the Vss sensor works fine, although there isnt much of the original sensor left. What I have learned from this is the sensor has to be exactly in the right place relative to the armature, or the speed reading gets very erratic. Literally a fraction of a mm can be the difference between success or failure. I used epoxy to lock the sensor in place when I managed to get a good reading. Hopefully road testing shows good results, however, rain and no roof is stopping that happening. Maybe this will be helpful for someone else.
  14. I also have connection issues with my g4x, especially when trying to download logs from the ecu. Sometimes it downloads the log with no issues, and other times it crashes part way through, and disconnects the ecu. Tried everything I can think of, however it seems very random. Old Hp laptop running win xp offline. Running in slow mode seems to make it better for downloading logs, but very slow and not the greatest for normal operation. Hopefully this gets fixed. Not sure if it's related, but I also have an small issue where the ecu sometimes does not come on when power is applied, and it takes turning the power of and on again, then it turnes on. It's not a major thing, as its obvious when it happens as the fuel pump doesn't prime, so you notice it strait away, but it would be nice if it didnt happen. Just thought I'd mention it incase it was related.
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