Programmable Timer and the PI

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newbi3
 
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Programmable Timer and the PI

Post by newbi3 »

Hello everyone, I have a CD4541B revision E timer chip on a toaster. I am wanting to send the output from this chip to the input of my RPI my only problem is I am a software guy. I am completely lost doing this I have found the data sheet for the chip: http://www.ti.com/lit/ds/symlink/cd4541b.pdf

I have a couple of questions.

How do I tell what the output of the chip is? The data sheet says 5V, 10V, and 15V how do I tell what it actually is?
If the voltage is above 5Vs how do I get it down to 5Vs?
Is there any documentation anywhere about using one of these with the GPIO on the RPI?

Thanks in advance for the help! I am a complete noob when it comes to hardware.

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lyndon
 
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Re: Programmable Timer and the PI

Post by lyndon »

Are you saying that this chip is controlling a toaster? As in, you're trying to read a chip controlling the toaster with your Pi?

If so, stop immediately and get more experience. Odds are that the chip is powered by 5V, but that 5V is likely derived from line voltage (120VAC) without any safety isolation and the slightest mistake can either send the Pi up in flames or leave you in a twitching mass on the floor.

The "correct" way to connect something like the RPi to a circuit floating at line voltage is with an optoisolator or other isolation circuit. I would strongly suggest that you start with a simpler, safer project and work up to something like this that has the ability to end your life.

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zener
 
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Re: Programmable Timer and the PI

Post by zener »

Lyndon raises a very good point, and is correct in what he said. I am not sure about the twitching part but you could definitely get hurt. Consumer appliances are not meant to be taken apart and messed around with, which is why they have all those warning labels on there! However, I am curious about what you are trying to do as there may be another safer way. Are you trying to determine when your toast is done?

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