Rpi cannot connect remotely via Ethernet with router

[yoshii]

Hello everyone!

I just bought my Rpi 3 and successfully installed Raspbian Jessie. I was able to access it remotely by using an Ethernet cable connected to my router. Then I was able to install OpenCV using Putty. But after connecting it to a monitor TV via HDMI to test my camera, I now can't access Rpi using Putty when I connect it back to my desktop via Ethernet.
Using the Fing app on my android, it seems that the Rpi is not connected to the network.

Any idea why this happened? Is there any way to access Rpi using Putty again? Solving this would be a big help because I find it troublesome accessing Rpi using my TV.

[broe23]

Have you tried rebooting it? What error are you getting in Putty when you access the IP for the Pi?

[yoshii]

Sorry for the late reply.

Yes, I tried rebooting it several times. The error is Connection timed out.

Any ideas?

[texy]

Are you sure you are using the correct ip address? Are you even sure the pi has an ip address allocated?
Is it in the same network range as your 'android'? Are you able to ping it?
Texy

[RaTTuS]

what power supply are you using 0 is it marginal ?

[FTrevorGowen]

Are you sure you are using the correct ip address? Are you even sure the pi has an ip address allocated?
Is it in the same network range as your 'android'? Are you able to ping it?
Texy

+1 The android app "fing" is useful for finding a pi (or two ... ) on your local network (I use it on my 'phone, 'twas originally suggested, IIRC, by @DougieLawson)
Trev.

[yoshii]

Are you sure you are using the correct ip address? Are you even sure the pi has an ip address allocated?
Is it in the same network range as your 'android'? Are you able to ping it?
Texy

Yes, I used the same IP ad since I was able to connect to it before. I am not sure if the Pi has no IP add since the only way I can know this is through the Fing app that I mentioned earlier. Is there any way to allocate an IP ad to my Pi?

[yoshii]

what power supply are you using 0 is it marginal ?

Yes. I am using a charger with 5V, 2.5A. I googled it and they said that 2.5A is enough

[texy]

Are you sure you are using the correct ip address? Are you even sure the pi has an ip address allocated?
Is it in the same network range as your 'android'? Are you able to ping it?
Texy

Yes, I used the same IP ad since I was able to connect to it before. I am not sure if the Pi has no IP add since the only way I can know this is through the Fing app that I mentioned earlier. Is there any way to allocate an IP ad to my Pi?

That's contradictory - just because the pi had a known ip before doesn't mean it's still the same. I am not familiar with FIng, but Trevor implied that it can be used to discover devices on the network. If so does it not find your Pi?
Yes you can fix the IP address of your pi, but its really not safe to do unless you know its a free address. Connecting your TV should have no effect on it's IP address allocation. Again an assumption but did you move the pi to the TV or move the TV to the pi? Most routers have a webpage that you can access in order to see what is connected - are you able to do this via your PC/laptop ?
Texy

[yoshii]

That's contradictory - just because the pi had a known ip before doesn't mean it's still the same. I am not familiar with FIng, but Trevor implied that it can be used to discover devices on the network. If so does it not find your Pi?
Yes you can fix the IP address of your pi, but its really not safe to do unless you know its a free address. Connecting your TV should have no effect on it's IP address allocation. Again an assumption but did you move the pi to the TV or move the TV to the pi? Most routers have a webpage that you can access in order to see what is connected - are you able to do this via your PC/laptop ?
Texy

I fixed it. And yes, I figured that the Rpi has no IP ad so I had to use a static IP.

Thank you so much for the help

[peterlite]

What model router?

I use a TP-link router and it lets me access the router as http://tplinkwifi.net/ or http://192.168.0.1/
From there I can allocate anything. If your router is allocating IP addresses automatically, the IP address depends on the sequence of network connections. The router might start at 192.168.0.100 the n go up by one each time a device connects. There will be a DHCP list in the router display. You can also see what is allocated to your device with command ifconfig.

When a device cannot connect, that could be a limitation of the router or a rule set into the router security. Investigate your router to find out the limitations.

A static IP address in your Pi has to be within the legal range specified in your router and not in the range used for automatic allocation because there could be a device that already has that address. Add your static address in the router to ensure there is no other use of the address.