Soldering irons to the ready, circuit help needed

The_blue · 27 Feb 2019 at 19:36

Hi all, i'm part of a dog flyball team. To help us a built a set of arduino timing lights using instructions i found online. I'm no electronics expert but eventually i followed the recipe and got them working...

Fast forward 2 years and a bunch of the infra red sensors had died so i decided to replace the whole lot but i've ordered the wrong ones! We can't afford to just waste them so i'm helping you guys can help..

This is the timing lights, the infra red sensors are along the middle in 2 rows and turn on and off when the dog breaks the beams (reflectors on another stand)

These are the old sensors, the old are PNP NO the new NPN and have NO and NC options. I hadn't seen the NPN issue

This is the input circuit, when the sensor is triggered it outputs 5v (i think)

What i want to do is use the NPN NO sensors to do the same. Any ideas how i can do this?

NoobCannon · 27 Feb 2019 at 19:37

Pancake?

The_blue · 27 Feb 2019 at 19:49

Basically

There must be a way to make this work though

Roland Butter · 27 Feb 2019 at 20:16

I'd much rather you explain what the flip a dog flyball team is.

The_blue · 27 Feb 2019 at 20:33

Gladly! It's a dog race, where a team of 4 dogs race to fetch a tennis ball over a set of jumps.
This is from crufts

it's easier to show than explain
https://youtu.be/9J2cgGrkT_g

Chris Wilson · 28 Feb 2019 at 04:25

The outputs of the old sensors go positive when triggered, the new ones go negative or release the negative rail. I think with another transistor or perhaps a small relay depending on the sensor's current handling ability you can convert the new ones, but are they wired all in parallel or individually? You may need a transistor or relay for each sensor it depends... If you post the question here you will almost certainly get some good answers:

http://www.eevblog.com/forum/beginners/

Good luck!

The_blue · 28 Feb 2019 at 07:21

Thanks for that, I've joined and asked

Chris Wilson · 28 Feb 2019 at 07:43

No worries, but it would do better in Beginners or the Projects section.

jpaul · 28 Feb 2019 at 07:50

the labels pictures are not close enough to discern which device is the sensor .. and even how many connections they have ?
can you find a datasheet on an english site eg rs. or use a online translator.

if there were just 2 connections then they maybe interchangeable ... if the resistance just changes with light exposure

Deleted member 77746 · 28 Feb 2019 at 09:57

Send them back and ask for different ones?

d_brennen · 28 Feb 2019 at 10:00

mrbell1984 said:
Send them back and ask for different ones?

This would be my first thought. If they are the same electrically, just bodge wire the connectors to where the correct item would be, otherwise send back and get the right components

The_blue · 28 Feb 2019 at 10:50

Can't send them back I'm afraid. I've trimmed the wiring, added plugs etc..

The_blue · 4 Mar 2019 at 11:32

Oh heck guys and girls, thought this would have been right up your street

Chris Wilson · 4 Mar 2019 at 11:42

You have got the answer on the EEVblog forum, bias it with resistors. I concur that will work.

The_blue · 4 Mar 2019 at 12:30

Really? Just heading over to check

Chris Wilson · 4 Mar 2019 at 12:52

E-mail alerts are your friend