Hello folks,
I've a problem when i'm using a 433Mhz Transceiver module with my Arduino UNO. Manufacturer of this module claims, it has 100m range outdoor and at the least of 50m indoors, when the transmitter module is operated at 12v. It doesnt come with any external Antenna. But it gives pretty decent range when im using the module without connecting to Arduino (i.e direct adapter 12v).
Now the problem im facing is, the module doesnt function at 12v from an external source when connected to Arduino.
The connection flow would be like: (Its actually a 4channel Wireless Relay Board):
Power Socket: 12v 1 A (Adapter)
GND --> Arduino's GND (Above pin13)
R1 ---> Arduino's pin2
R2 ---> Arduino's pin3
R3 ---> Arduino's pin4
R4 ---> Arduino's pin5
It doesnt respond to my signal when i connect in this fashion, but it responds quite well, when i remove my arduino and try to control it via the provided Toggle Switches.
If i use the recommended connection for Arduino, i.e Arduino's 5V, and GND to Transmitter's VCC and GND, it works, but i get pretty bad range(due to less Voltage input) , and it even struggles to function the same in next room.
I want to know, If i could boost my transmitter voltage to 12v, by still connecting to my Arduino UNO board with some changes in the connection or adding extra ICs and stuff.
It would be a great help, if someone comes with a solution for it, ive tried all over the internet, i really didnt get a solid answer for this problem. So decided to finally post it here.
Connect your transmitters Vcc to the Arduino's Vin pin and the ground to the Arduino Ground.
Then connect the Arduino to transciever through transistors to boost the signals.
As you havent posted the link correctly using the link icon ( it looks like a chain link ) then I can't be more specific because I can't copy and paste the link in an iPad.
The chip's logic levels scale with the supply voltage I suspect, so you need to power the transmitter
board from 5 or 6V, or use level shifting.
Can you read the chip's part number? If so it will probably have a datasheet.
You will get way better range with a proper aerial wire(*), I suggest using tuned lengths of wire
as described in the starter manual, but the wire length needs to be 17.3cm for 433MHz, not 30--35cm,
since a wire antenna is quarter-wave, not an end-fed dipole. This length includes any PCB trace length
that is not opposite ground-plane. The wire must point away from any metal conductors as much as
possible - stick out into space.
It says you have to cut the trace to the on-board antenna, note.
(*) 1km line of sight isn't unusual at low frequencies like 433MHz and a few mW, the range scales
with the wavelength because the antenna effective area scales with wavelength squared. Should
knock WiFi into a cocked hat! This does depend on both antennas being decent and the receiver
low-noise and sensitive and selective. This kit looks like its using remote power socket controller
chips which may or may not be well engineered!
With the Arduino disconnected, what is the voltage between GND and R1? If it is greater than 5 volts the radio may be driving current through the input pin's protection diode into the Arduino 5 volt supply. You may need voltage dividers to pull the voltage down to 5 or less.
In the manual:
"To switch the relays off, you will have to connect the corresponding header pin to GND and to switch them off you will have to leave them open"
Uhhh, slightly confusing...
I guess they mean: "use open collector outputs".
If you want to use a higher voltage, a small NPN transistor with emitter to ground, collector to transmitter switch pin, and base via 1k resistor to Arduino pin, would do the job.
KISS. A small aerial, as MarkT has explained, will do way more than a higher battery voltage.
My transmitters run on one LiPo battery (3.7volt), and I have a range of "the whole house" with a DIY sleeve aerial on the receiver, and coil aerials on the transmitters.
Leo..
A sleeve aerial is made by removing ~17cm of the outside insulation of a thin piece of coax.
And folding/pushing the braid 17cm back over the coax.
You will have a 2x16.5cm (33cm) dipole.
Leo..
According to the manual, and some educated guessing, you toggle the relay by connecting the remote pin to ground (low) for a short time.
Like pushing (and releasing) the button on the remote.
If you use an NPN transistor to do that, then the remote pin voltage can be higher than Arduino's supply.
Note that the logic reverses. A high on the Arduino is now a low on the remote pin.
Leo..
Grumpy_Mike:
Connect your transmitters Vcc to the Arduino's Vin pin and the ground to the Arduino Ground.
Then connect the Arduino to transciever through transistors to boost the signals.
As you havent posted the link correctly using the link icon ( it looks like a chain link ) then I can't be more specific because I can't copy and paste the link in an iPad.
I'm sorry i'm not getting it. Vin is supposed to be an Input for Arduino rite?, How can i supply an Input of Tranmitter to Input of Arduino. I dont get this part. Please explain.
And BTW these are the details available in that link i provided
A four channel relay board which can be controlled by a wireless remote which is connected to the receiver through a wireless RF link. The relays can be used to control 240 V appliances, motors, other electronic circuits, etc. The board can operate within a range of 100m when the remote is in line of sight and around 50m when indoors.
Each relay board comes with a adjustable address option which can be used to operate multiple remotes in the same area by assigning different addresses to each relay board. The remote provides 4 push switches which can be manually operated to control the relays. The input pins are also brought out to a row of header pins, which can be used to connect the remote to a microcontroller or an external circuit and control the relays through logic signals.
The RF link on this board works on the 433 MHz frequency. Both the transmitter and the receiver come with an onboard antenna and offer a compact and simple design. The boards also support an external antenna for better range and reception.
MarkT:
The chip's logic levels scale with the supply voltage I suspect, so you need to power the transmitter
board from 5 or 6V, or use level shifting.
Can you read the chip's part number? If so it will probably have a datasheet.
You will get way better range with a proper aerial wire(*), I suggest using tuned lengths of wire
as described in the starter manual, but the wire length needs to be 17.3cm for 433MHz, not 30--35cm,
since a wire antenna is quarter-wave, not an end-fed dipole. This length includes any PCB trace length
that is not opposite ground-plane. The wire must point away from any metal conductors as much as
possible - stick out into space.
It says you have to cut the trace to the on-board antenna, note.
(*) 1km line of sight isn't unusual at low frequencies like 433MHz and a few mW, the range scales
with the wavelength because the antenna effective area scales with wavelength squared. Should
knock WiFi into a cocked hat! This does depend on both antennas being decent and the receiver
low-noise and sensitive and selective. This kit looks like its using remote power socket controller
chips which may or may not be well engineered!
Exactly it works only when Chip's logic level is matched with the board. Thats why it's not able to function when its getting a power source from an external adapter.
Wawa:
In the manual:
"To switch the relays off, you will have to connect the corresponding header pin to GND and to switch them off you will have to leave them open"
Uhhh, slightly confusing...
I guess they mean: "use open collector outputs".
If you want to use a higher voltage, a small NPN transistor with emitter to ground, collector to transmitter switch pin, and base via 1k resistor to Arduino pin, would do the job.
KISS. A small aerial, as MarkT has explained, will do way more than a higher battery voltage.
My transmitters run on one LiPo battery (3.7volt), and I have a range of "the whole house" with a DIY sleeve aerial on the receiver, and coil aerials on the transmitters.
Leo..
A sleeve aerial is made by removing ~17cm of the outside insulation of a thin piece of coax.
And folding/pushing the braid 17cm back over the coax.
You will have a 2x16.5cm (33cm) dipole.
Leo..
Yeah, i know. I also didnt get anything worthy from that manual. It works only, when all my toggle buttons in Tx part is switched on, while im sending positive signal to R1..R4 from my Arduino's digital pin(If i choose to control via those header pins). It's logically not correct. It should funtion rite away whhen i provide a connection from my Arduino's GND to Tx GND and digitalWrite my pins to LOW without actually turning the toggle switches on all the time and sending HIGH from digital pins.
So you are asking me to use a NPN transistor in my digital pin of Arduino which is connected to the tx board?
Please recommend some antennas for me, which u believe, will work out for my board. It would be helpful
You may have got lucky with the retractable antenna .
There is a formula for calculating the correct antenna length
LengthAntenna = wavelength/4
wavelength = v/frequency | v = speed of light (300,000 m/s)
Let f = 433 Mhz
wavelength(m) = 300,000 m/s/433000000 Hz = 0.692 m
Antenna length = wavelength(m)/4
= 0.692 m/4 = 0.1730 m= 17.3 cm
This is the optimum length for a 433 Mhz antenna.
Any other length will yield poorer results.
The math doesn't lie.
Also, you can coil the 17.3 cm length around a pencil if the wire is solid copper hookup wire.
Otherwise , the sleeve antenna works best.
Have you measured the voltage across the push buttons ? (open/pressed)
Have you considered using NPN transistors or optos ?
Find out which side of buttons is positive and which is negative and then replace the buttons with open collector transistors.
If you are using the power jack then the Vin pin will have that power jacks voltage on it minus the series protection diode's forward voltage drop. So you can use the pin to power your transmitter.
Just look at the schematic of the Aarduino if you do not believe me.
Wawa:
That is the formule for an infinitely thin aerial.
Practically, you have to multiply the result by ~0.95.
Leo..
Practically, it's not that exact. A ¼λ dipole (monopole) really only works properly when mounted over a good groundplane at the feedpoint. As the OP won't have a proper groundplane the antenna will not conform to the theory and will have a poor VSWR. Best results will be obtained by adjusting the length by trial and error.
Practically, it's not that exact. A ¼λ dipole (monopole) really only works properly when mounted over a good groundplane at the feedpoint. As the OP won't have a proper groundplane the antenna will not conform to the theory and will have a poor VSWR. Best results will be obtained by adjusting the length by trial and error.
Retired after 40 years as a chartered engineer working mostly with RF and analogue electronics.
