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by ertank
Tue Oct 12, 2021 8:54 am
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Re: Alternative to relays

It is my lack of knowledge. I did not know such parts have diagrams and provided circuit is identical to part diagrams. Sorry about that. We build the suggested circuit with 2n2222 and 1k resistor. System works without being connected to the pay gate. Relay opens and closes. It was also working befo...
by ertank
Tue Oct 05, 2021 6:25 pm
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Re: Alternative to relays

So looking at your relays the second one will probably be active low, so you can use this circuit to interface it to the 3.3V gpio https://i.imgur.com/nHB4Xz9.jpg I am not sure about the first relay as it appears to have a jumper on board and I cant see what it does if you could post another pictur...
by ertank
Tue Oct 05, 2021 1:23 pm
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Re: Alternative to relays

I attached our relay(s) that we used to fix problem until now.

Other tests, I am trying to see if we can do it by ourselves.

Thanks.
by ertank
Tue Oct 05, 2021 11:51 am
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Re: Alternative to relays

On the Pi side, we are using following pins. Numbers are physical pin numbers Pin1 = 3v3 -> Relay VCC Pin3 = Trigger -> Relay IN Pın6 = Ground (-) -> Relay GND This is the relay we are using. https://www.direnc.net/5v-1-kanal-role-karti Machine translation of the relay details: Relay Boards are desi...
by ertank
Tue Oct 05, 2021 11:04 am
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Re: Alternative to relays

We investigated more and it turns out that our relay stays open. It can only be closed by cutting down power completely. Sometimes it is needed to hit on it to release the contact. So, my initial question still valid. Is there a way I can short circuit 220V power without using relay in a most possib...
by ertank
Mon Oct 04, 2021 4:27 am
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Re: Alternative to relays

There is far too little information to make a judgement; what evidence do you have that the relay is at fault? Just because the Pi Zero works fine when you are testing it, doesn't mean it works fine on site - the environment may be hotter, the wiring may be different (carrying electrical interferen...
by ertank
Sun Oct 03, 2021 5:29 pm
Forum: General discussion
Topic: Alternative to relays
Replies: 22
Views: 1645

Alternative to relays

Hello, First of all, I am not educated for electrics/electronics. So I appreciate simple explanations and links to suggested products, please. There is a simple solution we tried to apply to turn on a pay gate reading a barcode. That gate have a high voltage relay (I am not quite sure of its volts b...
by ertank
Sun Apr 04, 2021 3:16 pm
Forum: General discussion
Topic: Using Pi to allow internet only to registered users
Replies: 1
Views: 120

Using Pi to allow internet only to registered users

Hello, I am searching for an advise for combining necessary software here. I would like to use Pi to work as an internet logger & allow internet only to registered (thru a browser page) users. 1) Users will input their phone numbers and will be given access for 24 hours. After time is up. Their ...
by ertank
Thu Dec 24, 2020 9:34 pm
Forum: General discussion
Topic: Wrong screen resolution of Raspbian in VNC Viewer
Replies: 3
Views: 694

Re: Wrong screen resolution of Raspbian in VNC Viewer

I'm guessing you're attempting to use the fixed (but not default) resolution method? Are using Raspberry PIOS Lite, Desktop or Full? I set this resolution using "raspi-config" and not manually. There are some modes listed there, not the full list* available. I don't know if that is "...
by ertank
Thu Dec 24, 2020 8:55 pm
Forum: General discussion
Topic: Wrong screen resolution of Raspbian in VNC Viewer
Replies: 3
Views: 694

Wrong screen resolution of Raspbian in VNC Viewer

Hello, I am using RPi4 headless. I have problem with my remote VNC resolution. My settings and application versions are as following: pi@raspberrypi:~ $ uname -a Linux raspberrypi 5.4.79-v7l+ #1373 SMP Mon Nov 23 13:27:40 GMT 2020 armv7l GNU/Linux pi@raspberrypi:~ $ sudo apt list|grep realvnc-vnc-se...
by ertank
Tue Sep 08, 2020 7:14 pm
Forum: General discussion
Topic: SAM module
Replies: 6
Views: 368

Re: SAM module

topguy wrote:
Tue Sep 08, 2020 6:21 pm
That will definitly add up, yes. But now you have to safely get the keys from that server into the SAMs. And depending on who is running that server that might become hard or very hard ;)
I am happy that is no my job :D
by ertank
Tue Sep 08, 2020 1:38 pm
Forum: General discussion
Topic: SAM module
Replies: 6
Views: 368

Re: SAM module

How many keys are you typically aunthenticating for ? I cant really see how moving the authentication part locally to the pi will save you 2-3 seconds.. the SAM modules are not "faster" at encrypting/decrypting 3DES/AES than any modern computer. So you are only saving "network transf...
by ertank
Tue Sep 08, 2020 11:15 am
Forum: General discussion
Topic: SAM module
Replies: 6
Views: 368

Re: SAM module

What you are looking for ( should be googling for ) is "ID000 usb reader". Two examples: https://www.united-access.com/smart-card-reader-omnikey-cardman-6121-usb-5-pcs https://www.cryptoshop.com/gemalto-idbridge-k30-usb-shell-token-v2.html If they mention CCID/PCSC you will need to use &q...
by ertank
Tue Sep 08, 2020 8:49 am
Forum: General discussion
Topic: SAM module
Replies: 6
Views: 368

SAM module

Hello, We are using some USB RFID readers with ISO14443A/B support. These devices can read and write DES3Fire Mifare cards. Currently operation is working over a web service which takes 5-6 seconds for a single operation to complete. We are asked to be provided a SAM card for faster operation like o...
by ertank
Mon Jul 13, 2020 7:02 pm
Forum: General discussion
Topic: Copy file from Pi USB to PC
Replies: 6
Views: 303

Re: Copy file from Pi USB to PC

According to your earlier post you have a Raspberry Pi 3 Model B+ USB requires a Host - Slave relationship, as both your PC and RPi are USB Hosts you can not join them together with a USB Cable. Maybe Bluetooth could be an alternative ? I have a lot of different models. I am trying to make an offli...
by ertank
Mon Jul 13, 2020 4:02 pm
Forum: General discussion
Topic: Copy file from Pi USB to PC
Replies: 6
Views: 303

Copy file from Pi USB to PC

Hello, I do not know if there is a specific term used for what I would like to achieve. I have some files in my Raspberry Pi headless. I would like to connect Pi USB to a PC USB and want it to display only these files as read-only for copying to PC. It is not important for me the filesystem. It can ...
by ertank
Thu Jan 30, 2020 11:21 am
Forum: General discussion
Topic: WiFi icon meaning
Replies: 2
Views: 850

WiFi icon meaning

Hello, If you check this picture: https://www.piborg.org/image/catalog/PIBORG/blog/blog/pi-zero-wifi-setup-4.png You will see a disabled item in list of available wifi networks. It has an icon of a computer with stop sign on it. WiFi named "BTWifi-X". This is the first time I see this icon...
by ertank
Tue Dec 10, 2019 9:35 am
Forum: Advanced users
Topic: Secure app running on Pi
Replies: 9
Views: 997

Secure app running on Pi

Hello, We have a compiled application, GUI, running on Pi. We will be putting that application on an SDCARD/Flash Disk/mSATA and giving away with Pi itself. We would like to protect that application to be copy/paste to another place for reverse engineering, etc. We thought of; 1- Use a strong passwo...
by ertank
Wed Aug 21, 2019 10:28 am
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

Finally, I had a somewhat success using ADS1115 A/D converter. I used two resistors 100kohm (R1, for + leg), 10kohm (R2, for -leg) for reducing high battery voltage. That design theoretically reduce 50V down to 4.545V. This is as to online calculator here: http://www.ohmslawcalculator.com/voltage-di...
by ertank
Fri Aug 02, 2019 9:25 am
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

Is your SPI interface enabled? You can check with check with "Raspberry Pi Configuration" program or by looking at /boot/config.txt My SPI interface is enabled. If you connect the battery (-) to GND then you are not doing differential measurements. I did not understand what you mean by th...
by ertank
Fri Aug 02, 2019 12:02 am
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

davidcoton wrote:
Thu Aug 01, 2019 11:15 pm
The one obvious thing is that AGND should not be left disconnected, it should be joined to Pi 0V and battery -ve.
That link I shared and my connections are as following:
AGND is connected to Raspberry Pi Ground
Battery (-) connected to Raspberry Pi Ground
by ertank
Thu Aug 01, 2019 10:19 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

I think I fixed my wiring. Used same connections as in here: http://www.noveldevices.co.uk/rp-mcp3008 Battery + is connected to pin 1 of mcp3008 Battery - is connected to Raspberry Pi ground I get a reading once and then I don't have a reading (0 reading) for quite a long time. There is 3 seconds de...
by ertank
Sun Jul 28, 2019 12:03 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

Here is how I wired it up to the RPi. MCP3008 Pin --> Raspberry Pi Header Pin Vdd --> 5V Vref --> 5V AGND --> (floating, not connected) CLK --> SCLK (SPI) Dout --> MISO (SPI) Din --> MOSI (SPI) CS/SHDN --> CE0 (SPI) DGND --> Ground If you want to repeat my setup (and use AAA batteries). MCP3008 Pin...
by ertank
Mon Jul 15, 2019 3:27 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

https://www.aliexpress.com/item/3291407 ... 76c7ooFbkn

How about something like that? It says its communicating using serial. In theory it should be usable with RPi.

BTW, I am after measuring total volts on the serial connected batteries.
by ertank
Mon Jul 15, 2019 9:39 am
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 6169

Re: Want to measure battery volts

chipace wrote:
Sun Jul 14, 2019 8:27 pm
Are you going to show the battery voltages on a LCD screen, or use a web server on the RPi?
I am going to upload readings to a web server in the cloud. RPi will be headless.

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