steve
New Member
Posts: 9
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Post by steve on Sept 26, 2019 10:43:07 GMT
As basic as this no doubt is, please could you explain the Hall Effect sensor wiring?
There are 3 legs on each of the sensors and two sensors – one for wheel rpm and one for the motor
With 4 pins on the Echook for RPM board I am not sure where to wire things up.
Any chance of a diagram?
A second question would be how close do the sensors needs to be to the magnets?
Many thanks
Steve
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Post by Rowan on Sept 26, 2019 10:59:02 GMT
Sure Each hall effect sensor has three pins - 5v (Vcc), Ground and output (Vout), pin out shown below. The eChook board has 4 pins at the connectors - 5v, Ground, Motor RPM Input and Wheel RPM Input The 5v and ground connections are shared between the two sensors, and the Vout from the motor sensor goes to the motor input, wheel sensor to wheel input. Does that make sense? The sensors have to be very close to the magnets - a couple of mm. Best way to find out is to wire up a sensor to the eChook, wave it over a magnet and watch for a reading in the app. You'll get a feeling for what gap you can get away with. Datasheet: www.allegromicro.com/~/media/Files/Datasheets/A110x-Datasheet.ashx
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steve
New Member
Posts: 9
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Post by steve on Oct 7, 2019 13:37:56 GMT
I think have managed to short out the LEM sensor, how do I order another one ? I guess I need the capacitors as well please . The blue tooth appears to be working as it connects but keeps flashing that it is connected . I did have volts and Amps before we shorted it.
Thanks for any help.
steve
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Post by Rowan on Oct 7, 2019 13:54:10 GMT
Hi Steve,
The LEM sensors are pretty robust, is it definitely dead? Check the voltage readings on the connector for it... You should have 5v, and, 2.5v and 2.5v with no current flowing through the sensor. We've never managed to kill one and we've used them on all sorts of dodgy systems pre eChook...
If it is dead the best source for a replacement is farnell or RS. Both come up when you Google LEM HAIS 50p, they'll be about £20 - most expensive bit in the kit!
What does the app say when Bluetooth is flashing connected? Is the TX light on the Arduino flashing every .25 seconds?
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steve
New Member
Posts: 9
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Post by steve on Oct 7, 2019 14:13:51 GMT
voltages
from red pin 1 to green pin 2 = 4.23 pin 1 to pin 3 white 4.22 pin 1 to pin blue 4 5.05
if I go from pin 4 to 1 5.05 pin 4 to pin 2 .81 pin 4 to pin 3 .82
app is flashing up car successfully connected every second or so pow tx and rx are all constantly red
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Post by Rowan on Oct 7, 2019 14:25:31 GMT
Pin 4 is ground so those are relatively sensible voltages to be seeing. I don't think the LEM is dead. Arduino lights should be flashing though - I think you've managed to kill that, but the good news is that it's only a few quid. One of these: rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F151765624720Do you know how it shorted? Was it when you were working on it? If there is something plugged in with a short circuit you risk killing the new one when you plug that in, so check the outputs for continuity to ground and 5v before plugging a new one in
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steve
New Member
Posts: 9
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Post by steve on Oct 7, 2019 14:40:58 GMT
I am an amazon fellow ,
how does this look ? ( just checking it is the correct one not the price)
Elegoo for arduino Nano v3 , nano board CH340/ATmega 328p , pack of 3 £ 10.00
steve
It was my fault , the lem touched the main switched as I moved the car and shorted on one of the capacitors , I re soldered it ?
Steve
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Post by Rowan on Oct 7, 2019 14:49:08 GMT
That looks right to me You should be fine to re-upload the code to it and plug it in then.
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Post by Stuart on Oct 7, 2019 15:49:08 GMT
Hi. I'm new to the forum. Just having a look at echook for the first time. Have you thought about using bike ANT+ sensors for RPM so that there's no wiring or magnets involved?
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Post by Rowan on Oct 7, 2019 19:44:43 GMT
Hi Stuart - welcome We didn't really to be honest - the idea behind the eChook was to keep it simple, understandable and cheap. The ANT+ sensors are probably a very good way of doing it, but they're more expensive and more complex. We tried to keep all the sensors and circuits on the eChook to A Level (and most are GCSE if my memory serves...) electronics level. Cost wise, the hall effect sensors are about 50p each too. Overall I think we've achieved that, but there are sure to better ways of doing things than we have, and we've left some spare pins for teams to play with. One team has added digital temperature sensors to the board and put the code up on GitHub which is excellent! If anyone fancies looking at adding ANT+ sensors that would be an awesome addition.
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