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by Qua294
Fri Jan 17, 2020 3:42 pm
Forum: Advanced users
Topic: Running Raspbian from USB Devices : Made Easy
Replies: 245
Views: 82899

Re: Running Raspbian from USB Devices : Made Easy

Hi, Sorry if it was answered already (I read the whole 9 pages but maye missed it) - how much a "while" can be when writing a 30GB USB flash drive? I'm well over an hour now (buster lite version), with the RPi 3B green led flashing here and there, the USB drive led flashes all the time and the putty...
by Qua294
Sat Mar 16, 2019 9:16 am
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

Hi there, reporting back after implementation - The inbound part with the opto-isulator works like a charm! The outbound (locked status report) does not. It either jumps indefinitely between locked and unlocked (once every ~100ms) or reports 'unlock' all the time, no matter the real status. To save ...
by Qua294
Sun Mar 03, 2019 1:55 pm
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

Actually it will be a little harder using GPIO 2 or 3 (the two that have hardware pull-ups). The 1K8 value is quite strong, and with a 1K0 series resistor on the contact the switch-closed GPIO voltage will be 3V3*1K0/(1K0+1K8) = 1V17. That may not be enough to switch reliably, the specified VILmax ...
by Qua294
Sun Mar 03, 2019 11:19 am
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

Well, that's about it. I think we have concluded everything... I will now start to collect all the parts needed for this mini-project.
Thank you very much again for everything!
by Qua294
Sun Mar 03, 2019 10:39 am
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

Great. So checking GPIO2 ( https://pinout.xyz/pinout/i2c ) - it says it is an I2C pin which has a builtin 1.8K pullup resistor. Can I use it instead of GPIO24 + external 1K resistor? Also, a bit off-topic, what's the recommended DIY way to connect wires, resistors and so on with RPI when in "product...
by Qua294
Sun Mar 03, 2019 10:10 am
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

or are thy saying its just a dry contact that can handle 24 at 100mA maximum
Yes, that is what they are saying.

Thanks.
by Qua294
Sat Mar 02, 2019 8:18 pm
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

First and foremost, thank you very much for your patience and for taking the time to draw the schema! In parallel to your answer, the lock support team also answered me (but not in English, so I will translate here the relevant parts): For the inbound wires (i.e. "A" and "B" - the ones that I use to...
by Qua294
Sat Mar 02, 2019 4:47 pm
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

more detailed information required or a web link to the lock or its manual, You are right, sorry for that. I'm afraid the lock is not that common yet and the site doesn't hold lots of info, the most relevant section is this: https://www.sds-tech.com/technical-specification/ , but it also doesn't de...
by Qua294
Fri Mar 01, 2019 7:45 pm
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Re: Close circuit on a dry contact

Thank you pcmanbob for your detailed and prompt response. Let me start first with the simpler things on your reply - 1. the lock is of SDS-tech with a dry contact card (which expose the interface I mentioned) 2. so I only need to connect voltmeter to the two wires in order to measure the voltage? (c...
by Qua294
Fri Mar 01, 2019 4:24 pm
Forum: Beginners
Topic: Close circuit on a dry contact
Replies: 16
Views: 1335

Close circuit on a dry contact

Hi, This is a totally noob question - I have a lock that I can toggle by closing a contact on a dry contact relay - the two wires I'm shortening do not carry any voltage and I only need to perform the short for a 'moment' in order to toggle the lock (one time open, consecutive time close and so on)....

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