Sensor for toy

This topic has 29 replies, 14 voices, and was last updated 13 April 2015 at 14:52 by Michael Gilligan.

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4 November 2013 at 14:41 #22930
OuBallie
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@ouballie
Morrison’s Halloween toy
Advert

4 November 2013 at 14:41 #134583
OuBallie
Participant
@ouballie
Some advise sought please.

Other half bought one of Morrison's Halloween Petrifying Prisoner toys at half price yesterday.

Unfortunately someone had removed/half inched the small front facing activation sensor, with just two bare wires where it should be.

Does anyone have any idea what that sensor is and can I get something similar.

The 'toy' works via the 'Test Me' button.

I will be in credit if I can get it to work via a sensor.

Power is by means of three AA batteries, but haven't checked if connected in //le or series.

Geoff – Ready to machine the drill vice bolts.
4 November 2013 at 15:37 #134585
Sub Mandrel
Participant
@submandrel
Hi Geoff,

What does said prisoner respond to? Light, movement or… if he's cheap and cheerful, it's probably a phototransistor or photodiode.

Neil
4 November 2013 at 16:27 #134590
Bazyle
Participant
@bazyle
Can you measure voltage on wires.

Perhaps you can see if putting a resistor across the wires makes it work.
4 November 2013 at 18:10 #134601
OuBallie
Participant
@ouballie
Neil,

Cheap and cheerfull it most certainly is, and other half said a bunch of ladies nearly had pups when one of them activated the thing by moving her hand in front of it, and it burst into life with flashing eyes and voice. SHMBO joined in the laughter as well.

There is a 4mm wide slot in a front facing moulding that houses the sensor.

I never bothered to inspect them when they where first put on the shelf for sale, so cannot describe the sensor.

Bazyle,

Will check the voltage.

Thank you both for your quick responses.

Geoff – I WILL have to replace the damaged power feed worm gear in the lathe. Oh effing bother!
4 November 2013 at 18:50 #134604
Richard Marks
Participant
@richardmarks80868
Most likely to be an infra red sensor similar to those used in the detectors in outside intruder lights.
4 November 2013 at 19:15 #134608
nigel jones 5
Participant
@nigeljones5
just take it back and get another???
4 November 2013 at 20:59 #134620
Sub Mandrel
Participant
@submandrel
I think it will be a photo diode and a simple bridge/comparator circuit with two different time constants. Any sudden jump in the voltage across the diode (caused by a shadow) will set off the alarm. it may be more sophisticated with a microprocessor these days, of course, but any circuit like this will be self compensating, so any photodiode wired to be reverse biased should work to some extent (if I'm right!).

Neil
5 November 2013 at 13:30 #134661
Grizzly bear
Participant
@grizzlybear
Hi OuBallie,

Take the duff one as far as Morrisons car park. Go in store and buy another one. Go to car, swap duff for good, march back into store, have tantrum, then ask for a refund, job done.

Bears can stoop pretty low, they have to, to catch them salmon.

Regards, Bear..
5 November 2013 at 13:57 #134664
V8Eng
Participant
@v8eng
I'm with fizzy on this one, why not just take it back for a refund or replacement?

Edited By V8Eng on 05/11/2013 14:00:42
5 November 2013 at 15:40 #134682
Springbok
Participant
@springbok
take it back not worth the hastle and time to fix it

bob
5 November 2013 at 16:04 #134685
OuBallie
Participant
@ouballie
Would if I could, but it was on an end of line 1/2 price sale, and was the last one.

It works, but only manually.

Still have to check the voltage at those bare wire ends.

Geoff – Proof reading/checking BH600G Apron oiling write-up before posting. Yes it's done! Photos up first though.
5 November 2013 at 17:07 #134688
mark costello 1
Participant
@markcostello1
Why not look online for a description and picture of the toy, might find an answer there.
5 November 2013 at 19:07 #134706
Sub Mandrel
Participant
@submandrel
Geoff, if shorting the wires together then separating them sets it off, it's probably a photodiode.

Neil
6 November 2013 at 09:50 #134750
OuBallie
Participant
@ouballie
Thanks for all the responses.

Neil,

Correct diagnosis, that is what happens. The slot looks to be the right size at 4mm.

New photo Album – Missing Sensor

Geoff – Bad night, but I will get into the workshop with luck later, but in carefully does it mode.

Edited By OuBallie on 06/11/2013 09:51:38

Photo insert actually working on the iPad now. Well done whoever sorted this out!

Edited By OuBallie on 06/11/2013 09:54:07
6 November 2013 at 11:44 #134764
Springbok
Participant
@springbok
bin it
Bob
6 November 2013 at 20:21 #134790
Sub Mandrel
Participant
@submandrel
It's the petrifying pensioners around here that scare me.

Neil
27 November 2013 at 15:16 #136534
OuBallie
Participant
@ouballie
Update.

Have tried three photodiodes:

Two with a dark 'lens' one being IR Filtered but they only work when a bright light is aimed at them

The third has a clear lens that works when light is interrupted.

It appears to need a proximity/movement sensor of some sort.

Ready to file this in the Lost Cause folder and just let her indoors operate it manually, BUT I will be in credit with her if I can get it to work properly

More photos added.

Geoff – A week wasted with nothing done.
27 November 2013 at 17:33 #136542
Les Jones 1
Participant
@lesjones1
Hi Geoff,
If you have any LDRs (Light dependent resistors.) you could try one of them. They tend to be more sensitive than photo diodes. Maplin no longer seem to stock them so I do not know where you could buy one without sending away for it.

Les.
27 November 2013 at 17:45 #136544
Steve Withnell
Participant
@stevewithnell34426
Geoff – I have some big LDR's somewhere I acquired from street lamps as a kid, let me dig out what I have in the scrap box and I'll post the resistance readings, see if one of those will do the trick.

Steve
27 November 2013 at 21:39 #136566
Steve Withnell
Participant
@stevewithnell34426
Only managed to find one – but it is big, around 25mm. it's pretty much open circuit in the dark (>50Mohm) and 500K in bright artificial light. Sounds like the wrong characteristic to me.

Steve
29 November 2013 at 03:37 #136639
I.M. OUTAHERE
Participant
@i-m-outahere
Hi Geoff,

Just out of curiosity if you hook up the IR filtered PhotoDiode can you get the unit to activate by pointing a TV remote at it and pressing one of the buttons ?

Ian

Edited By SLOTDRILLER on 29/11/2013 03:37:56
29 November 2013 at 09:43 #136645
OuBallie
Participant
@ouballie
Thanks for looking Steve.

Will give that a try Ian.

Geoff – Hopefully workshop time today
3 December 2013 at 10:59 #136923
OuBallie
Participant
@ouballie
Ian,

Your suggestion works.

Does that mean it needs a far more sensitive IR diode? If so, how do you specify it?

My qualifications are all with HV, with bits and bytes just making an appearance when I left the profession.

Other half said the ladies where waving their hands in front of the inbuilt sensor to activate it.

Progress is being made, with thanks to all the help received.

Geoff – Washing down and hung
3 December 2013 at 17:26 #136944
I.M. OUTAHERE
Participant
@i-m-outahere
Hi Geoff,

Isit possible that there could be an IR LED in parallel to the photo diode ?

I was thinking that it could just be a simple comparator circuit that senses the voltage of the negative side wire and that negative side wire could have a small resistor in series that along with the current limiting resistor for theIR LED would create a voltage divider and you also get a voltage drop across the LED.

So by placing the Photo diode in parallel with the IR LED and it's current limiting resistor you have a light activated bypass switch as it creates a short across the led / resistor and this would create a very short voltage spike that a comparator could sense .

the other resistor would be internal to the sensor circuit in the doll , maybe if you can measure the voltage on the leads and then measure the resistance of the low side ( negative ) lead to the battery negative ?

I was playing around with a laser training tool that I made a couple of years ago for pistol shooting , it uses a sound activated laser mounted to the gun that activates a Photo transistor in a receiver on the other side of the room .

I dug the receiver out and set it up and sat my tv remote on top , then pressed a button and if I waved my hand past at about 2 ft away there reflected IR beam off my hand activated the receiver .

Just a thought.

Ian
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