NJK-5002-C Hall Sensor

Here is the link to the sensor I am talking about. Now the problem is that according to the label it has as shown, it says that Brown wire goes to V+, Blue wire to V- and the Black wire goes to Signal. THe output depends n the input and the signal will be in operating voltages of 6 to 36 Volts DC. I am working on these sensors for the past 5 days. No datasheet, No information online, (Company name is Omdhon, not omron) and I can't seem to get a change in its output if I get a magnet either normal or rare earth strong magnets into its proximity (8mm). If anybody knows what should I do to make it work, it would be a great contribution and will save me. 1. Whether Pull up is requires or not. 2. What should be the configuration to make it work. Seriously I am going mad.

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    \$\begingroup\$ Have you tried it with a piece of steel? That doesn't look like a true hall sensor, but rather a plain old proximity switch. \$\endgroup\$ – R Drast May 12 '15 at 15:51
  • \$\begingroup\$ Also you might need a pullup on the output. If you post a close up of the label we might be able to help more. \$\endgroup\$ – Jon May 12 '15 at 15:53
  • \$\begingroup\$ wayengineer.com/… According to this link, sensor is NPN type and you should be measuring signal in relation to positive side of input. It also mentions that you shouldn't connect directly to power supply, though it does not seem to specify what you should do. Several of the selling sites mention that it comes with a small magnet and will detect at 10mm, so if you have it hooked up right it should be working at 8mm. \$\endgroup\$ – I. Wolfe May 12 '15 at 16:07
  • \$\begingroup\$ @RDrast - If you google the part number all of the sites that turn up call it a Hall sensor driven proximity switch, and several sites mention it coming with a magnet you can use and detect at 10mm. \$\endgroup\$ – I. Wolfe May 12 '15 at 16:08
  • \$\begingroup\$ @Wolfe - the warning about not connecting it directly to the power supply is for the 2-wire type, which are essentially 4-20mA current switches. The 3-wire type has dedicated power connections. It is basically an exact copy of the Omron sensor range. \$\endgroup\$ – Jon May 12 '15 at 18:13

The output for that sensor is an open collector type. This means it is like a switch that connects the signal wire to ground (0V) when activated, and leaves it open circuit when not active. To observe this changing you need to connect a pull-up resistor (1K-10K should be fine) between the signal wire and the power supply. It should then work correctly.

The Chinese data sheet is very confusing, but I'm am 95% sure it is an inductive proximity sensor not a hall effect. These work by generating an alternating magnetic field at the blue end of the sensor. When a piece of metal (any metal, not just iron) is brought near this end, the magnetic field is affected and the sensor detects this and activates the output.

  • \$\begingroup\$ Yes. I will try it. Maybe metal strip will work then they will be just plain proximity switches I guess. I am too fed up from my 7th day of working on them. The problem is that there is no manual available from chinese company... \$\endgroup\$ – Naeem Ullah May 14 '15 at 21:13
  • \$\begingroup\$ FYI - I have used sensors like this (they are all copies of Omron sensors) from a Chinese company called Lanbao with very good results. Phidgets also stocks this brand, so they seem to have a decent reputation. Got some like the ones you are using for around $8 USD in 250pcs quantities direct from Lanbao. Had quite mixed results with other vendors from Alibaba before that. \$\endgroup\$ – Jon May 15 '15 at 17:42

I know this is an old question, however I just bought one of these Hall Effect Sensors that came with a Tachometer. To answer your 2 questions:

  1. A 1K pull up resister is recommended.
  2. Connections: Brown to V+; Blue to V-; Black is signal.

Note: The small LED at the back of the sensor should light up when in proximity. It only works in conjunction with a magnet and the side of the magnet facing the sensor has to be the correct polarity. If you have your connections right but are not getting the led to light up at close proximity, try reversing the magnet.


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