weight sensor?!?

[computer]

hi,

anyone know of a way to modify a standard office chair so it could detect if it was being sat in or not? (ie weight sensor or something)

thanks

 

[jbeng]

At my previous job, I could have sworn my boss had one of these hooked up to my chair. I could sit there and work for hours and not see him, but as soon as I got up (bathroom break, etc.), he would be there when I got back, asking where I'd been.

You could use a weight sensor - which could be a load cell (and probably expensive), or an arrangement similar to a touchscreen on a computer monitor, or just a set of sensitive pushbutton switches to detect weight (or lack thereof).
You might be able to use a heat sensor to detect the occupant's body heat or maybe even an optical sensor (light to the sensor is blocked when someone is sitting). There are several ways this might be accomplished.
JB

 

[bryan1]

Maybe you sew a pressure mat into the seat that way as soon as anyone sits on it a pulse could be sent to a buzzer,light or anything you desire..

Just a thought

cheers Bryan1

 

[computer]

lol,

it's for my pc. I have a switch on my KVM to blank the screens, and if I hooked that up via an IR remote or wireless signal to a chair sensor then as soon as I got up from my chair it'd blank (basically locking) my screens.

i think a switch is the easiest so it'll use less battery power (I'll make a little box on the bottom of my chair with a 9v battery or something)...

 

[bryan1]

okies Computer,
Then maybe just use a push button switch located under the seat so when you sit on it or get off it turns on or off and as far as 9 volt batteries go use a 3-9 volt converter so you can use nicad AA batteries...

cheers Bryan1

 

[computer]

ok so I don't want to sit on it and break it how about the following:

2 bits of small card with a tactile switch in between them with 2 flying leads coming off through a hole drilled in the bottom of the seat connected to the 1st box. the 2 bits of card create a more even response.

the 1st box sends multiple on or off IR commands using a PICAXE08 or similar from 4 ir transmitters positioned in the 4 different directions so whichever way my chair is facing it'll transmit out. then a small IR reciever under my desk connected to a decoder chip (another picaxe08 would do it) and then to the switch on the KVM.

I can use 3 1.5v batteries in the chair as that'll give ~4.5v - enough for a picaxe

 

[bryan1]

now that sounds like a top idea computer, I haven't delt into the pixaxe chips, just a decision I made after buyin up a heap of PIC gear. But an idea like yours pulled of would make a good contribution to my electronic mag siliconchip. It's an Australian magazine so I don't know if you get it in England ??

Cheers Bryan1

 

[computer]

ahh! I missed your first post

a pressure mat like used on security alarms would probably work

 

[computer]

now that sounds like a top idea computer, I haven't delt into the pixaxe chips, just a decision I made after buyin up a heap of PIC gear. But an idea like yours pulled of would make a good contribution to my electronic mag siliconchip. It's an Australian magazine so I don't know if you get it in England ??

Cheers Bryan1

you own siliconchip magazine? I've heard lots about it but I've never got a copy

I've got plans for everything now drawn up - I just needed help with the sensor - let me know if you want more info.

Ben

 

[bryan1]

[[/quote]

you own siliconchip magazine? I've heard lots about it but I've never got a copy

I've got plans for everything now drawn up - I just needed help with the sensor - let me know if you want more info.

Ben[/quote]

sorry if I misled you Ben, I don't own sicilonchip magazine I've just been collecting them for about 5 years. Thats how I got into electronics but once you have the project finalised post it to www.siliconchip.com.au and they will probably put it their circuit notebook and if it's good enough then they give give you a pretty good prize. Make sure you check it out


Cheers Bryan1

 

[computer]

hmm but I'm not subscribed to SC - sounds quite expensive though looking at the subscription page... :-/

 

[stevez]

All of the chairs in all of my offices are such that the center support column is compressed somewhat (1/2 inch or so) -sufficient for a simple microswitch to be used. If my chairs represent the standard office chair then this might be a solution.