Indoor wireless communication

What would be the transmitter for going through house walls? I bought a MX-RM-5V at 5 volts but it is not going through a single wall. Soldered a spring antenna on both transmitter and receiver. Not sure if I can make them work or if I need a different receiver transmitter combo. Going about 75 ft through about 5 walls. Any advice would be greatly appreciated.

Depends on what the walls are made of. However, a better antenna always helps.

For 433 MHz, use 17 cm of wire, not a spring, or better, a balanced dipole (33 cm from tip to tip), as shown below. Connect one end of the dipole to ANT and the other to GND.

Do you know what length of antenna for 315mhz?

315 MHz should have no problem with most walls - assuming you're not in a bomb proof bunker - even with a simple spring antenna.

Does your WiFi penetrate those walls? Mobile phone signals?

caniread:
Do you know what length of antenna for 315mhz?

Try a Google search on;

'Do you know what length of antenna for 315mhz?'

Speed of light / frequency /2 (for dipole) * 0.97 (diameter reduction factor)
= 300/315/2*097 = 0.46m = ~46cm (tip2tip).

I prefer a DIY vertical sleeve aerial.
Better matching to the transmitter/receiver, and a a circular footprint (if that's what you want).
Leo..

Check whatever specifications you have on the transmitter, but most of these units can take up to 12v. Vcc. There is more power and better range if they are supplied with more than 5v.

Just regular walls in a home. Wifi does reach those distances in my home. I made a 9" long antenna out of a strand of cat5 cable but it is only still good for line of sight. I will try hooking up to 9 volt battery next.

I made a 9" long antenna out of a strand of cat5 cable

A correctly sized dipole antenna on TX and RX would work MUCH better.

Don't expect too much from a cheap MX-RM-5V superheterodyne receiver.
The right aerial on the receiver, and some distance between receiver and Arduino (digital hash) could maximise range, but 75ft through 5walls is pushing it.
Leo..

9 volt does not seem to be working either. Any suggestions on what will work that is not too expensive?

Don't expect too much from a cheap MX-RM-5V superheterodyne receiver.

I think those are the super regenerative and not the super heterodyne units. The super heterodyne units can be significantly better, and still inexpensive. With monopole antennas I had a pair working from a greenhouse to a station inside the house through several walls and about 30 meters.

cattledog:
I think those are the super regenerative and not the super heterodyne units.

I think you're right. Mixed them up.
The good ones have a SAW filter on the board.
Leo..

Thank you, I will by a pair to try out.

I see a lot of receivers but not matched with transmitters. Do I just buy the regular 433mhz transmitter?

Looking on amazon so I can get it quick.

A bit more expensive but sure to work would be a pair of LoRa modules. Or maybe even use WiFi as you said that is known to work (i.e. two ESP8266 based modules).

By the way, that are some rather flimsy walls then. In my home WiFi has a problem penetrating three thin walls, or two load bearing ones.

The first link is the same crap.
Leo..