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by akash614
Wed Jan 29, 2020 6:57 pm
Forum: Other projects
Topic: Multiple MCU to Raspberry Pi communication
Replies: 0
Views: 381

Multiple MCU to Raspberry Pi communication

Hi i have project where there are few rs232 boards connected to computer and the computer does the processing of switching on and off but i wanna upgrade i want to use something like CAN BUS or I2C for this like all MCU or slaves connected to RPI by GPIO Pins and these MCU sent data to RPI and in re...
by akash614
Mon Nov 25, 2019 11:54 am
Forum: Python
Topic: SyntaxError : invalid syntax Compile
Replies: 5
Views: 389

Re: SyntaxError : invalid syntax Compile

But as I said, (msg.payload == uid): isn't a valid statement. The comparison msg.payload ==uid will give a boolean answer (that nothing uses so will be thrown away) and the colon after it is a syntax error. The colon used like this marks the separation of a statement (if, while, for, def etc.) and ...
by akash614
Mon Nov 25, 2019 11:50 am
Forum: Networking and servers
Topic: PiHole, PiVPN, DNSCrypt and NAS on RPI
Replies: 1
Views: 668

PiHole, PiVPN, DNSCrypt and NAS on RPI

i wanna buy a raspberry pi 3 or 4 and secure my home network on it by having pihole to block ads pivpn for secure surfing DNSCrypt to encrypt my DNS NAS for extra storage for all my devices or movies to watch from it and if needed secure my wifi network can i use this all on a single pi to secure my...
by akash614
Sun Nov 24, 2019 5:49 am
Forum: Python
Topic: SyntaxError : invalid syntax Compile
Replies: 5
Views: 389

Re: SyntaxError : invalid syntax Compile

The colon at the end of that line doesn't make sense, was there supposed to be an if at the start of the line? The indentation looks suspect at times too, especially around that line, the if current_card three lines down is indented to a level that doesn't match the lines above (though it may do if...
by akash614
Sun Nov 24, 2019 4:09 am
Forum: Python
Topic: SyntaxError : invalid syntax Compile
Replies: 5
Views: 389

SyntaxError : invalid syntax Compile

def on_message(client, userdata, msg): global current_card global last_time print(msg.topic+" "+str( msg.payload)) # Check if this is a message for the Pi LED. if (msg.topic == '/sys/server'): # print("current_card {}".format(current_card)) (msg.payload == uid): # print("uid {}".format(uid)) last_t...
by akash614
Sat Aug 31, 2019 2:07 pm
Forum: Other projects
Topic: Adding data in groups to mysql database
Replies: 0
Views: 176

Adding data in groups to mysql database

Hello Guys i made a rfid based Attendance system and i made a php page to add data into database but i would like to add multiple data to the database in one click like scan cards one after another and keep adding cards to database at last after clicking add and these cards should be scan able With ...
by akash614
Mon May 20, 2019 4:14 pm
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

I have added a diode for that and did not like to have the both input and output at in other direction same time causing it to destroy Does the forward voltage of the diode give you a problem :geek: You could also "place" the "input select" (so to speak) in front of the buck converter, will this he...
by akash614
Mon May 20, 2019 12:39 pm
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

i am able to light a led without any problem as it is still glowing low and even a red led is working properly but i will add for extra safety Try to connect a led to a real powersupply and set to output to 3.3V and check the current (the led will be damaged). You could also run the led on a batter...
by akash614
Mon May 20, 2019 11:21 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

You are wrong here. Because the resistor is fundamental needed if you want to power a led correctly. And it doesn't matter if it is a smd led or a 5mm led. Also, in this way you are "overloading" the output of the Rpi and the output could die. Because that the maximum is <16mA spec and if you conne...
by akash614
Mon May 20, 2019 10:50 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

Are you sure the LCD led backlight doesn't need a resistor. Don't forget the resistors in front of the "LED indicators" Yes i am sure cause they are 5mm and running in without resistor and these were tested really Also, how are you different power rails connected. For example: how is the 5V+ connec...
by akash614
Mon May 20, 2019 9:41 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

i am using a mosfet to switch between power like if low activate if high deactivate so it is easy to handle with an additional diode and so i guess i will use 2x lipo battery and convert that to 5v as there will be more capacity usage Can you post a circuit diagram of what you have? Then we can see...
by akash614
Mon May 20, 2019 6:24 am
Forum: Other projects
Topic: Client-Server RFID System with RPI and ESP8266
Replies: 6
Views: 1092

Re: Client-Server RFID System with RPI and ESP8266

This is a nice idea i can connect multiple clients to one server as i am new to this and never did ESP8266 programming can you please help me out in setting one of these projects To go arduino ide programming route, Perhaps look at this lib to read the rfid h/w https://github.com/Jorgen-VikingGod/E...
by akash614
Mon May 20, 2019 6:04 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

You don't want it to power at the same time as whatever power supply us plugged in, so you'll need more circuitry to determine when the power is cut and then switch to your backup power source fast enough without the voltage dropping. A non trivial task, in my experience. There's also no current ba...
by akash614
Mon May 20, 2019 5:30 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

Mentioned it before? Where in this post? If you can’t solder SMD then you should seriously consider a pre-made UPS. Almost all of the IC solutions created this millennium have been SMD parts. The newest/best stuff is all SMD. —Bud dont worry about that i already made a mini ups out of mosfet just i...
by akash614
Sun May 19, 2019 6:51 pm
Forum: Other projects
Topic: Client-Server RFID System with RPI and ESP8266
Replies: 6
Views: 1092

Re: Client-Server RFID System with RPI and ESP8266

If your looking for a roadmap for your project? I would suggest looking at Mqtt and hosting a broker on your Pi to facilitate communication to and from your esp8266 devices. Using Mqtt to handle the coms all your connected devices need do is publish the sensor output, and your current system just n...
by akash614
Sun May 19, 2019 3:53 pm
Forum: Other projects
Topic: Client-Server RFID System with RPI and ESP8266
Replies: 6
Views: 1092

Re: Client-Server RFID System with RPI and ESP8266

Two possible ways: 1) When you define the server in SQL you could point this to the Pi via IP address or name. You need to set the SQL server to allow connections from the network though. 2) Use MQTT to pass messages between the units. Put the broker on the SQL server and create a simple subscripti...
by akash614
Sun May 19, 2019 1:33 pm
Forum: Other projects
Topic: Client-Server RFID System with RPI and ESP8266
Replies: 6
Views: 1092

Client-Server RFID System with RPI and ESP8266

Hi Guys i made a Raspberry Pi based RFID Attendance System of connecting all MFRC522 LED LCD Relay to RPI and it works very well but i want to make a bunch of these connected to main server Reference Code for attendance System : https://github.com/danjperron/MFRC522-python but i cant add a raspberry...
by akash614
Sun May 19, 2019 6:38 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

Check this out. The UPS is powered by a single supercapacitor that will provide power for about 30seconds, depending upon the size of the supercap and the current drain of the Raspberry Pi. A 100F super capacitor works just fine for a Raspberry Pi Zero W. You will need a larger supercap for a Raspb...
by akash614
Sat May 18, 2019 1:56 pm
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Re: Small UPS for Raspberry pi

There are quite a few UPS and battery hats available for the RPI. Some are very sophisticated and expensive. Option 1: This is a cheap one I found on Bangood, and I can vouch that it works 100%. https://www.banggood.com/Geekworm-UPS-HAT-Board-2500mAh-Lithium-Battery-For-Raspberry-Pi-3-Model-B-Pi-2B...
by akash614
Sat May 18, 2019 6:15 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 6076

Small UPS for Raspberry pi

Hi Guys i am having a project of Entrance system running but i cant power it down directly by unplugging it i just want to switch of the mains power and the battery should kick in and shutdown the raspberry pi at same time and turn off the raspberry pi safely which saves the sd card from corrupting ...
by akash614
Sat May 11, 2019 1:46 pm
Forum: Other projects
Topic: Adding a Master Card Database to Existing RFID System
Replies: 2
Views: 356

Re: Adding a Master Card Database to Existing RFID System

I would just add an extra column (field) in the database to say if the card is a master card or not. Saves duplicating all the table coding and keeps the data structure clean. Have a read of these principals . You can then just check this flag when the card is read and if it’s a master skip over th...
by akash614
Sat May 11, 2019 5:41 am
Forum: Other projects
Topic: Adding a Master Card Database to Existing RFID System
Replies: 2
Views: 356

Adding a Master Card Database to Existing RFID System

Hi Guys i have made a RFID System of Database from which there are cards in database when ever scanned it checks from them and they can be accessed only once a day so i thought of adding a master card database where all the master cards are stored and when ever scanned it first check from master car...
by akash614
Tue Apr 23, 2019 2:08 pm
Forum: Automation, sensing and robotics
Topic: Adding a master card to rfid system
Replies: 6
Views: 500

Re: Adding a master card to rfid system

topguy wrote:
Tue Apr 23, 2019 2:03 pm
Then you have a place in your code where you do a lookup in the database, and instead of doing that lookup you first check if the cardId matches the mastercard ID. And if it does you just dont do the database check.
i want the same procedure but i would like to have a code as it is a bit difficult
by akash614
Tue Apr 23, 2019 1:53 pm
Forum: Automation, sensing and robotics
Topic: Adding a master card to rfid system
Replies: 6
Views: 500

Re: Adding a master card to rfid system

i have a very complex rfid system And you have made this system yourself ? Can you explain how it works because the words "master card" doesnt make much sense unless we have an Idea what its supposed to be "master" of. it is like whole database of cards and each card is scanned once a day and trigg...
by akash614
Tue Apr 23, 2019 1:32 pm
Forum: Automation, sensing and robotics
Topic: Adding a master card to rfid system
Replies: 6
Views: 500

Re: Adding a master card to rfid system

The example prints the UID ( Unique Identifier ) for the card so you have to add some code that checks that value against the known UID of you "master card". And if the UIDs match you light the led/trigger the relay. add a master card that only i have access to the system But what do you really mea...

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