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I am using these 433MHz modules. According to the product information, I can supply the transmitter from 3-12 Volts. I am sending the data from an arduino (5V data) and want to power the transmitter with 12V that I am still be able to receive the data some meters away from the transmitter.

Can the transmitter still determine if it was a high or a low, when it is powered with 12V and the max data voltage is 5V or do I need a driver circuit?

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Old question but still relevant and high in google results.

Just connect your 5V data output to the data input of your emitter and the 12V from your power supply to the VCC of your emitter. I've done it and it works.

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  • \$\begingroup\$ With the specs only consisting of 5 lines if text in a wiki, first hand experience is the only way to tell if it works (assuming it will will work again if it did once). \$\endgroup\$ – Andreas Feb 28 '17 at 23:38
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The device is basically a TX433 rebranded by a few folk and although the data sheet doesn't explicitly indicate one way or the other, page 2 shows it connected to a HT-12E encoder (also running from 12 V) and it could be presumed that the data from the encoder is 12Vp-p: -

enter image description here

Here is the HT-12E spec and the logic input levels are stated as related to Vcc so it's a reasonable assumption that the output levels are also related to Vcc.

Conclusion - you'll need a small driver circuit to convert from 5V logic to 12Vp-p. Maybe something like this: -

enter image description here

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  • \$\begingroup\$ I have laying around some mosfets I power LEDs with. bit they are huge and extremly overdimensioned. What ICs do I need to convert (two-way would also be good, than I can also drive the receiver with 12V) \$\endgroup\$ – Tobi Mar 18 '14 at 17:33
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    \$\begingroup\$ Would a Max662A do the job? datasheets.maximintegrated.com/en/ds/MAX662A.pdf \$\endgroup\$ – Tobi Mar 18 '14 at 17:36
  • \$\begingroup\$ Probably not - you need an N channel mosfet (or NPN transistor) as a common source/emitter level shifter. \$\endgroup\$ – Andy aka Mar 18 '14 at 17:39
  • \$\begingroup\$ What do I need to search for - or can you supply an example circuit? What specs would it need to have? \$\endgroup\$ – Tobi Mar 18 '14 at 17:44
  • \$\begingroup\$ @Tobi - I've added a circuit that should work but it inverts so you need to logically invert the output from your MCU. \$\endgroup\$ – Andy aka Mar 18 '14 at 18:17
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There's a bit more info about the receiver if you scroll down the page you linked. It says that the receiver will produce a HIGH signal that is half Vcc, so if you power your receiver with 12V, then you'll get 6V for HIGH signal.

Unfortunately nothing is said of the transmitter input HIGH signal levels in that page.

The only way of knowing is to ask the vendor or to test it. One could imply the same signal level for the transmitter, but that's not healthy.

I copy the specs below.

Basic Specification:

  • Frequency: 433Mhz.
  • Modulation: ASK
  • Receiver data output: High - 1/2 Vcc, Low - 0.7v
  • Transmitor input voltage: 3-12V (high voltage = more transmitting power)
  • Transmitting range (work at 5V): 40m indoor, and 100m in open air
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  • \$\begingroup\$ so i will need some kind of driver circuit? \$\endgroup\$ – Tobi Mar 18 '14 at 17:18
  • \$\begingroup\$ will the receiver have better receiving power, when I drive it with 12V? If so, it would solve another problem. \$\endgroup\$ – Tobi Mar 18 '14 at 17:31
  • \$\begingroup\$ There, I edited and fixed my answer. But I don't have a definite answer to your question anymore, sorry. Andy aka seems to have made further inferences using the transmitter datasheet. That may help you further. \$\endgroup\$ – Ricardo Mar 18 '14 at 17:31
  • \$\begingroup\$ Well, I've used similar receiver modules before and I'm pretty sure that the receiver supports 5V input supply ONLY! Watch out or you will burn the thing. \$\endgroup\$ – Ricardo Mar 18 '14 at 17:32
  • \$\begingroup\$ But again, the spec seems to tie the receiver data output level to Vcc which implies it takes a range as its input supply. Well, these specs are really confusing. Sorry I can't help you further. \$\endgroup\$ – Ricardo Mar 18 '14 at 17:36
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The receiver will only work on 5V - think about it - why would a higher voltage help it receive more! On the other hand the transmitter WILL give more power at 12v and I had no problems continuing to supply it data from a 5v Arduino-type-chip. The range almost doubled. I'm using a 17cm wire on the transmitter and nothing on the receiver. Here's a blog I wrote on the subject. Forget the 40m indoors - that only works if your walls are made of paper. With a cottage and stone walls I reckon half of that.

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    \$\begingroup\$ Welcome to EE.SE, Peter. The original poster (OP) is actually asking if he will be able to send data using the Arduino 5V logic HIGH if he powers the transmitter with 12V. The answer is actually NO, because the transmitter logic level threshold for logic HIGH is 12V/2, or 6V. He won't be able to give a logic HIGH to the transmitter data pin with 5V from the Arduino output. See Andy's answer and mine in which we try to explain the issue. But I also got confused with the question and started the same way you did. You can see that in my answer edit history. \$\endgroup\$ – Ricardo Jun 25 '14 at 0:16
  • \$\begingroup\$ Nice blog post, by the way. +1 \$\endgroup\$ – Ricardo Jun 25 '14 at 0:17
  • \$\begingroup\$ Yeah pretty nice blog, just read it all. \$\endgroup\$ – KyranF Nov 6 '14 at 11:27
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then 9v supply to transmitter would a compromised solution? 9v/2 = 4.5v. So, Arduino can use 5V to make it HIGH.

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