Coincidence, or.....?

Unread post by **RichardW** » 12 Mar 2004, 12:58

I have been going to the local college for a welding course since September (MIG before Christmas and now TIG). Last week when I came out I couldn't get the remote to open the Xantia - must be batteries thought I. Changed them and still no go. Oh well, must have given up the ghost - start using the other one [;)]
So, last night I went along again, came out, and now the OTHER remote has stopped working[:(!] The light comes on, and I can see that it is making some IR signal, but it won't open or lock the car.
Now, that's either a massive coincidence, or I have fried the circuits with the magnetic field around the welder (key in my pocket where it's been on every occasion)[:(] I did use the same welder for the last 2 weeks, but I am sure I have used this one in the past.
I am going to try recoding the plips into the car, but am not hopeful!
Are the plips hard programmed into the chip, or are they EPROM type?
Ah well, at least I won't have any more alarm problems, as I can't set it now[:D]
PS: Meant to add - if you've got Xantia IR plips, keep them away from welding machines!!

tomsheppard · Unread post by **tomsheppard** » 12 Mar 2004, 13:35

A quick tip. If you or a friend have a digicam, point the remote at it. The sensor can see IR and it comes up white on the digicam's screen. This works with all IR remotes, so if the telly's on the blink... You can now see the effect of changing batteries.

AndersDK · Unread post by **AndersDK** » 12 Mar 2004, 13:37

Richard -
Despite the heavy magnetic field from a TIG welding transformer - the IR Plip should not be sensitive to this - as it has no antenna.
Besides that - the HF/VHF energy from the TIG would be limited.
Have you tried inside the car using the Plip agaisnt the receiver dome - with some 0.5m distance ?
The red pilot lamp on the sender means the circuit is activated - but it does NOT mean for sure the IR signal is transmitted - as the IR sender device is a separate IR LED - exactly looking like the red pilot lamp LED.
Chances are you have the very common problem with a dry solder joint in the sender - exactly on this IR sender LED.
That would be a feasible explanation for both units playing up within short time.
Try here for pic's/advice on repair/programming the IR Plip units :
http://www.rwbsmith.plus.com/citroen2/plip/

tomsheppard · Unread post by **tomsheppard** » 12 Mar 2004, 13:40

Plips are hardwired. The useful links section takes you to BX do it yourself. There is plip info there re coding. Plip receivers can be very sensitive to high energy magnetic fields and you might have sent its transistors to their ancestors. If the sensor has seen the arc, there is a remote(!) possibility that it has been blinded by the light but re reading your posting, only the key has been near the welderand it is most unlikely to be damaged. You can therefore rule out the receiver until you have checked the ir for emission. Just 'cos the light comes on doesn't mean that the receiver is getting a full code. If the battery is weak, the output falls off and the full data (Sent more than once to verify it) doesn't get to the receiver, so you're off the guest list. This again you will see on the digicam. the bright spot of the ir gets dimmer.

Unread post by **RichardW** » 12 Mar 2004, 13:58

Thanks Tom - I have a digicam, so I'll have a go, although I am sure I can see the plip firing visually. The timing is WAY too much of a conincidence for it to be just failure of the plip - both were working well before hand and are now completely dead, so I guess something has got fried / disrupted. Oh well, more fun!

tomsheppard · Unread post by **tomsheppard** » 12 Mar 2004, 14:31

This is the nature of coincidence. BTW How can you see some IR signal?

Unread post by **RichardW** » 12 Mar 2004, 14:43

>BTW How can you see some IR signal?
Dunno, but looking at the remote in the dark I can see that one pulses twice when the button is pressed, and the other about 4 times. This occurs in about half the time the light is on on the side of the plip. Presumably the IR sender makes some visible light, and I can see quite long (right way?) wavelength light.

tomsheppard · Unread post by **tomsheppard** » 12 Mar 2004, 14:50

OK, I understand that. Some of us martians can see near IR and I have been momentarily blinded by a truvelo in the dark. The fact that these devices emit different pulse patterns points to batteries. Clean the plip lenses, the car's glass and the lens on the receiver before engaging in electronic warfare. When you remove the receiver to do this, let me know the number of the chip and I'll see if I can come up with a test diagnostic routine for you.

William · Unread post by **William** » 12 Mar 2004, 16:30

I've had a similar problem with two Xantia keys.
On both occaisions it was the IR lens that had dry solder connections.
It's quite easy to get to the cicuit board and re-solder the pin ends on the back.

tomsheppard · Unread post by **tomsheppard** » 12 Mar 2004, 16:55

That'll be the LED. Perfectly good idea to solder it as a precaution. You won't blow anything up.

AndersDK · Unread post by **AndersDK** » 13 Mar 2004, 08:08

Richard -
Have you had your seing abilities checked ?
You're right that infrared is longwave light radiation.
I can't belive your eyes reacts to infrared waves. That would mean you're able to see heat radiation too - as heat is (partly) radiated as infrared wave energy.
Any nearby room radiator would radiate a lot more infrared energy - then any IR remote.
All IR LED's are known to radiate residual energy in the visisble light band - so small it's only recognised with no ambient light.

Dave Burns · Unread post by **Dave Burns** » 13 Mar 2004, 14:00

I would think it very likely that the High frequency generated by the Tig for arc start could damage a chip, especially if while learning you have zapped yourself with it via the filler rod.
Its known that static electricity is a killer to computer chips, thats why my kid allways wears a wrist strap when building machines, and thats very low level static, the h/f on some of our tigs at work will jump 1.5 inch from electrode to earth, thats a serious spark and it wakes anyone up that is half asleep if they get a taste of it[:D]
Dave

NiSk · Unread post by **NiSk** » 13 Mar 2004, 14:23

Any welding equipment that generates a spark (thereby including both MIG and TIG welders) produces enough energy to fry the delicate inputs to the I/Cs in your remote if you have it close enough (and your pocket is definately close enough). I'd guess that you've done both of them while on the welding course. XM and Xantia remotes are reknown for using up batteries at an alarming rates - this is the first stage of decline, where the built-in protective diodes on the I/C inputs have been fried (often by static), causing the remote to comsume power even when not being used. The next stage is that they stop working at all.
//NiSk

Homer · Unread post by **Homer** » 13 Mar 2004, 16:03

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by AndersDK</i>

I can't belive your eyes reacts to infrared waves. That would mean you're able to see heat radiation too - as heat is (partly) radiated as infrared wave energy.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Two types of IR, Near IR which is close to visible light and is used for IR nightvision cameras etc. Can be picked up by most (but not all) digital caneras. It's not the first time I have heard of people being able to see the flash on a truvelo either.
Heat IR is further along the spectrum.
Note, because some digital cameras have a system to block IR you'll need to check the camera against a known good transmitter such as your TV remote.
More IR/digicam info

tomsheppard · Unread post by **tomsheppard** » 14 Mar 2004, 02:14

No! the remotes both give pulse outputs. Therefore they are not destroyed by the Mig output. When I was doing research in 2000 with blue laser chips, these were indeed sensitive to high energy discharges but today's mig and tig welders peacefully coexist with their CMOS control circuitry. Ir remotes emit between 880 and 940 nM, the spread of the 880 will emit light in the near Ir region. It is however a very bad isdea to squint into one to see it because the high energy IR that you cannot see may be doing your retina no good at all.
NEVER LOOK A LASER IN THE EYE.