Phidgets Forums

Hi!

I have bought a number of motion sensors of type TDL-758. This raises the output signal to the same as the input voltage when triggered, for a time that can be adjusted.

I use 24V in my house control system, because the easiest relays to get hold of use 24V to switch.

I want to use phidgets to read when the motion sensor triggers. But I am not quite sure how to connect this. My 24V power source can produce 1A. If I simply connect:

- the ground from power source to ground on TDL-758 and G on 0/16/16 input
- 24V from power source to + on TDL-758
- output (now 24V) from TDL-758 to input port 0 on 0/16/16

is that principally correct? Or will I fry my phidget board? Do I need to put in some resistance anywhere? Or does the TDL-758 limit how much power it puts on the output?

I tried it now and with 24V, when I plug things in, the TDL-758 switches the output on. Then it keeps switching off shortly and then on again every 15s, even if the sensor is in a box.

If I use the 5V outputs on the 0/16/16 as voltage for the TDL-758, it never triggers, although specifications say that 5V should be enough.

Very greatful for any help on this!

Update: I started asking also for 8/8/8, but since found that that board should have max 15V on the input ports.

Best regards,

Knut

The maximum digital input voltage on the PhidgetInterfaceKit 8/8/8 is 15V DC.

If the motion sensors are happy at 5V, you can just use the 5V pin on the InterfaceKit to power the sensors and then you can read the 5V signal back into the digital inputs.

Edit: If you're using the 1012 - PhidgetInterfaceKit 0/16/16, the maximum digital input voltage is 30V so you'll be fine reading the 24V line from the sensors. (Again, you could also just use the 5V pin on the 0/16/16 to power the sensors)

Thank you very much!

Yes, I found out about the 8/8/8 input <15V. So I tested on a 0/16/16.

If I use the 5V output from the board, nothing is triggered.

If I attach 24V external power, the TDL-758 just goes constantly off/on...

I googled the TDL-758 and it looks like there's a timer adjustment potentiometer on the board. Maybe you can try adjusting that?

Thanks for the tip!

The timer is on 15s. If I connect only 24V in and not the output, it works like it should. After a movement, it triggers on and stays like that for around 15s, then goes down.

But as soon as I connect the output, it switches on instantly when I connect power and only blinks off shortly every 15s.

Update:

it seems I have been confused by the lights on the 0/16/16. The light on input port 0 lights when the output from the TDL-758 is connected, whether the voltage (measured on 0/16/16 connectors G and 0) is 24V or 0V???

I haven't connected to pc yet, but I would guess it would show the port as on as long as the light is on?

If the light on the 0/16/16's input is on, it means it's seeing greater than 4.2V differential between that input and its own G pin. Do you have a multimeter so you can double check what this sensor is putting out?

Hi again!

You are really helpful here, I think we are getting close to the root.

I thought all the G's on the 0/16/16 where connected on the board? If not, why is it not the V between the input port 0 and the G next to it that define if the port is on?

Which port is the boards own G?

After reading your last post, I measured between input port 0 and the 0-voltage output port of 0/16/16 and that actually showed around 5V even when the V between G and I0 was 0!

So I connected so that the 24V power supplys ground, the ground of TDL-758 and the ports G (next to I0) and the 0-port next to 5V output where all connected.

But still the same problem. So I'm guessing I'm not still not connecting to the correct "board ground"?

The G pins on the 0/16/16 are all connected. When I said "its own G pin" I just mean the 0/16/16's G pin, rather than the ground of the sensor or power supply.

You're measuring 5V between an input pin and an switched-off output pin on the 0/16/16? It definitely seems like there's some kind of grounding issue going on here. Or there's something metal underneath the board shorting the output pin to the nearby 5V pin. Does this behavior occur for any of the other digital output pins?

You shouldn't have to connect digital output pin 0 to ground (but should connect the 24V ground to one of the 0/16/16 G pins). You need to figure out where that 5V on output 0 is coming from, because even when that output is active it will be at ground voltage because these are open collector (switch-to-ground) outputs.

After lowering the power voltage to the TDL a little, that works as it should.

After a lot of testing, I found that the input ports on the phidget stay on after they once have been lit, even if I remove the wire!

So I tested on another phidget 0/16/16 (which is in use for house warming control, so I was a little reluctant). But on that one it works as it should. If I touch an input port with the output wire from the TDL while it's on, the port lights up, if I remove the wire it goes off again.

So I have to check up return policies for phidget boards. I bought this one a couple of years ago, but it's never been used and stored in it's bag all the time.

Thanks for helping me out, mparadis!