I took the sender off my knackered gearbox, just to see the wave form, current and voltage it produces. I just connected a bit of tough rubber tube between the sender drive shaft and a bit of a bolt in the drills chuck. It works a treat.
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I took the sender off my knackered gearbox, just to see the wave form, current and voltage it produces. I just connected a bit of tough rubber tube between the sender drive shaft and a bit of a bolt in the drills chuck. It works a treat.
Usually simple = good. Why make it complicated?Quote:
Originally Posted by mudnut
This is the Plug and play gauge cluster test 'bench'. (Don't look at the failed paint job) The speedo signal is at 175 Hz at 60 kph. The power supply drops to 11.9 volts when the cluster is powered up, so this reading isn't accurate. I have to pull the supply apart and check it out. It needs a better voltage regulator and a couple of capacitors fitted to lift it to 13.8 Volts under load. The trip meter and odometer also clocked up 4 ks during the test so that was a bonus.
The readings on the road for 60 kph with Mrs mudsane driving were 170 hz. Which is very close to the stationary test I did yesterday, but could be her interpretation of what position the needle is at 60.
Anything below 50 was unreadable, but that may have been the way I had set up the oscilloscope.
I tried the scope on my tacho input, but it showed a 9v bias with a minute square wave on the very top. Again, it is probably the way I interpreted the Chinese instructions. I will talk to a mate who does Dyno tuning and get his opinion on what signal to expect.
Set the scope to AC coupling. Then turn up the vertical amplitude.Quote:
Originally Posted by mudnut
Thanks, The "toy" only has DC coupling. I have been trying to learn to navigate the device. I have posted the link to the instruction manual in the multimeter thread.
OK - I have used many scopes and never heard of one without AC coupling. You live and learn.Quote:
Originally Posted by mudnut
http://www.ebay.com.au/itm/291039883...84.m1423.l2649
@ Mudnut this any good for you
Thanks for finding that meter, TD, I have a Jaycar QM1551 meter. You have reminded me to take it back, as the the duty cycle mode is unable to measure square waves correctly.
To date, I have had trouble finding information regarding the test procedures on tachometers. I took the plug'n'play test bench to a retired electronics tech's place and spent the afternoon running tests and recording results. He is going to draw up a circuit that will amplify the test signal produced by the Oscilloscope. it should be an easy build, which I am looking forward to. And because I'm too tight to pay out for a portable 12v sig gen, I will use a small variable speed 12v motor I have found in the shed, to run the speedo sender up to 110 kph.