Rf transmitter receiver — Parallax Forums

# Rf transmitter receiver

Posts: 2
Hi sir ,
Please I have RF transmitter and RF receiver I'm using for the transmitter the HT12E encoder which I put between the pin number 15 and 16 resistor 1M
And for the receiver I use decoder HT12D which I put between the pin 15 and 16 resistor 5.1k
I'm using this circuit to on leds in the receiver by pushing the switch in the transmitter but nothing it's working I'm thinking maybe the resistor 5.1k it's wrong .can someone please help me???

• Posts: 2
Hello
Can someone help me please??
• Posts: 11,961
Welcome to the forums. You need to provide a lot more information.
Are these Parallax products? Part numbers?
What microcontroller are you using.
• Posts: 11,961
edited 2017-09-13 19:13
haythem wrote: »
Hello
Can someone help me please??

You may have to wait a while. Most people on the forum are volunteers so it takes some time to get a reply
• Posts: 175
haythem wrote: »
HT12E encoder which I put between the pin number 15 and 16 resistor 1M

Encoder frequency is approximately 3kHz (per curves on datasheet; nearly flat from 5V to 12V). Holtek recommends that the Decoder frequency be approximately 50x the Encoder frequency. So, the target Decoder frequency is 150kHz.
haythem wrote: »
And for the receiver I use decoder HT12D which I put between the pin 15 and 16 resistor 5.1k

The power supply for the Decoder must be known, because the frequency curve (again, per datasheet) is not as flat as the curve for the Encoder. To achieve 150kHz:
At Vdd = 5V, the resistor should be approximately 51K (10 times the value that you tested).

So, your hunch is correct. The 5.1K value is a fraction of the range shown on the Holtek datasheet and will quite certainly produce a bad result.
• Posts: 175
Sadly, when you google "ht12d and ht12e", one of the first links is an Instructable that uses the exact same values (1M and 51K).

It admonishes, "IMPORTANT: Don't change the value of this resistor if you make that your circuit it doesn't work"

Datasheet and inter-webs had all of the necessary information at your fingertips.
• Posts: 1,148
That's what I'm seeing too 1.1meg on the Xmitter and 51K on the receiver. (Electrosome.com)