Photoeye/LED/other stuff to connect to Raspberry Pi starter kit


#1

I just ordered a couple Raspberry Pi I/O Started kits and will be very excited when UPS delivers today, to prototype a bag counting system. However, I think I need some hardware to wire into the I/O (I am more of a software guy). Can anyone recommend a photo eye / photo switch and LED or light I can wire in to make blink as the photo eye is triggered?

Thanks,
Josh


#2

The Pi starter kit comes with two input modules, 10-32v DC and 90-140v AC.
The photo eye should output a signal that is going to work with either of those two voltages.
Not sure where you usual buy from, so just picked Amazon as an example…
Here is a photo eye with a good range of distance and output signal;

I like this one as it works more on a beam, so you can put the reflector on the other side of the bag track.
Also this sensor has a really good range of voltages that it will run off, so you should be covered in that regard.
The sensor output is a dry contact, so you could easily run the sensor off one range of voltages, and use a different voltage source on the sensor relay and then into the Opto module.

If you don’t mind buying another Opto module, you could buy the G4IDC5-SW module. It is designed to accept dry contact inputs just like this sensor uses.
But if you have a small transformer or DC supply in the range of the the two input modules from the starter kit, you can start with those - so you have a choice is my point.

I’m more of a hardware guy, so feel free to ask any questions.
Wondering what your software language of choice is going to be for the Pi?


#3

Hi Beno,

That definitely looks like what I want, but my company requires me to use a corporate purchase order to buy anything so I will try to figure out how to get. I do not mind buying other Opto modules to try, so I will order a couple of those modules.

What is the correct name for a LED light you can wire to a digital output? I do not think I want an alarm light or anything that blinks, strobes, or makes noise, just something I can turn on and off in software while I learn.

For software language, for the backend I want to try out Node-RED, for the front end that the operator would interface with, I am thinking PHP as I know that language very well.

Thanks again,
Josh


#4

No problem. I wondered about the whole Amazon thing, but figured it was a quick start if nothing else.

For the LEDs, you have some options… In someways I might be tempted to go with something like this LED stack light;
http://www.newark.com/edwards-signaling-products/113ss-rga-aq/lamp-stackable-ind-red-green-amb/dp/22H5035?exaMfpn=true&categoryId=&searchRef=SearchLookAhead&searchView=table&iscrfnonsku=false
It gives you 3 lights to test software against - thinking sequencing here - and at the end of the test phase, it might get some use in your facility.
This one I linked to works on either DC or AC, so it will work with either of the two output modules you got with the Pi starter kit. Note you will need one output module per LED, so in this case, you would need 3 of the same type.
When it comes to the solid state switches that are built into the Opto output modules, you just have to be careful that the LED light you pick has more load than the leakage current of the module, otherwise the LED light will not turn off.
Just check the specification for the LED and you should be on your way (this stack light for example is 5 watts, so should be fine).

Since Node-RED is now included on the groov AR1 we have been doing a lot more with that of late. We did some hacky PHP back in the day…
Sounds like you will be controlling the world in no time.


#5

If your company comptroller (or whoever handles purchasing) is willing to do so, Amazon will set you up with a corporate account, accept purchase orders, provide whatever documentation and security you want, bill your company/government entity however you want, etc. I went through this where I work and finally got them to open an Amazon account because there is so much stuff I can get there quickly, easily, etc.

I’ve even bought a reasonable amount of Opto-22 gear from Amazon over the last few years!