# Read from RX/TX Pins
**URL:** https://community.particle.io/t/read-from-rx-tx-pins/26375
**Category:** Hardware
**Created:** [October 7, 2016, 12:32am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375 "2016-10-07T00:32:45Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 7, 2016, 12:32am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/1 "2016-10-07T00:32:45Z")
Hello,
I have been working on the Sparkfun Photon WeatherShield and I have attached a Gieger Counter to the USART pins. I know that I have to use Serial 1 to see the data sent. But what do I write so that I can read from that pin.
I have written-
```cpp
Serial.begin(9600);
Serial1.begin(9600,SERIAL_8E1);
if(Serial1.available()){
client.publish("IFF ","IF");
sensorstring=(char)Serial1.read();
client.publish("Radiation: ", sensorstring);
}
//snprintf(payload, sizeof(payload), "Radiation : %f ", radiation);
client.publish("Radiation: Second Try", sensorstring );
```
Can somebody please help me out!!
I need this to be done fast.
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 7, 2016, 5:08am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/2 "2016-10-07T05:08:52Z")
> [@skasat](#):
>
> I need this to be done fast.
Then you should probably provide as much info as possible to start with.
Omitting what your actual trouble with above code is and posting a contextless code snippet makes things slower for yourself.
---
### Author:  [@nrobinson2000](https://community.particle.io/u/nrobinson2000)
#### Post date: [October 7, 2016, 1:38pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/3 "2016-10-07T13:38:30Z")
You need a way for the Photon to read strings properly from Serial:
Have a look a this:
```cpp
String readString = "";
void setup()
{
Serial.begin(9600);
Serial1.begin(9600);
}
void loop()
{
while (Serial1.available()) // While receiving characters over serial...
{
delay(3); // Necessary delay
char c = Serial1.read(); // Read the character
readString += c; // Add the character to the string
}
readString.trim();
if (readString.length() > 0) // If a string has been read...
{
Serial.println("Received: " + readString); // Send the parsed string to Serial for debugging
parseCommand(readString); // Do something with the string...
readString = ""; // Clear the string
}
}
```
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 7, 2016, 7:33pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/4 "2016-10-07T19:33:04Z")
Hello,
Thank you for your response-
This is the data which is coming via the RX pin. I have read this via my terminal but even after following your method, I am not able to read anything. The data is empty.
Please help me out!
Data coming in-
[mightyohm.com](http://mightyohm.com) Geiger Counter 1.00
> **[Geiger Counter](http://mightyohm.com/blog/products/geiger-counter/)**
>
> Introducing the MightyOhm Geiger Counter kit! Assembly Instructions Case Assembly Instructions Design Files Source Code Usage Instructions Support Features: 100% Open Source Hardware! LED and piezo…
CPS, 2, CPM, 2, uSv/hr, 0.01, SLOW
CPS, 0, CPM, 2, uSv/hr, 0.01, SLOW
CPS, 1, CPM, 3, uSv/hr, 0.01, SLOW
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 7, 2016, 7:39pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/5 "2016-10-07T19:39:11Z")
I had given all the code which I had written for the RX/TX pins-
This is the new code which I am running but I am still having the data as empty/null.
Do we have to initialize RX/TX pins before reading from Serial1? Or does the data automatically transmit to Serial1?
```cpp
while (Serial1.available()) // While receiving characters over serial...
{
delay(3); // Necessary delay
char c = Serial1.read(); // Read the character
readString += c; // Add the character to the string
//snprintf(payload, sizeof(payload), "Radiation Speed: ", readString);
client.publish("TRY1: ", readString);
}
readString.trim();
if (readString.length() > 0) // If a string has been read...
{
Serial.println("Received: " + readString); // Send the parsed string to Serial for debugging
client.publish("TRY2: ", readString);
readString = ""; // Clear the string
}
```
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 7, 2016, 8:08pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/6 "2016-10-07T20:08:12Z")
> [@skasat](#):
>
> The data is empty.
What does that mean? What _data_ is empty?
You say
> [@skasat](#):
>
> This is the data which is coming via the RX pin. I have read this via my terminal but even after following your method, I am not able to read anything.
Did you now read _this data_ or are you _not able to read anything_?
That's rather confusing 😕
I'd say that `delay(3)` in that loop is rather long.
You could go with [`Serial1.readStringUntil()`](https://docs.particle.io/reference/firmware/photon/#readstringuntil-) instead, since you know what data you're looking for.
* * *
> [@skasat](#):
>
> I had given all the code which I had written for the RX/TX pins-
That's assuming that there is no issue burried in supposedly unrelated areas of your code.
> [@skasat](#):
>
> Do we have to initialize RX/TX pins before reading from Serial1?
That's done via `Serial1.begin()`.
> [@skasat](#):
>
> Or does the data automatically transmit to Serial1?
That depends on your wiring and your datasource (sensor).
Some sensors transmit unasked others need a request command.
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 7, 2016, 8:11pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/7 "2016-10-07T20:11:25Z")
Okay, so 2 scenarios-
1. When I connect my Geiger counter to my computer via a FTDI I am able to get information transmitted on Putty.
2. When I connect my Geiger Counter to Photon via the RX pin, I am trying to read that data, it is coming as null/empty.
What can I do?
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 7, 2016, 8:19pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/8 "2016-10-07T20:19:08Z")
You’ve got TX of the sensor hooked up to RX on the Photon and vice versa?
Try this most simple sketch
```cpp
void setup() {
Serial.begin(115200);
Serial1.begin(9600);
}
void loop() {
static uint32_t ms;
while(Serial1.available()) {
Serial.write((uint8_t)Serial1.read());
}
if(millis()-ms > 1000) {
ms = millis();
Serial.print(".");
}
}
```
and see what your serial terminal gives you then.
BTW, why were you using 8E1 for `Serial1` while the sensor seems to require `8N1` (which is default for `Serial1` anyway)?
> **[Usage Instructions](http://mightyohm.com/blog/products/geiger-counter/usage-instructions/)**
>
> How to use it! Easy, turn on the switch and listen for clicks! Watch the LED, it will flash every time a beta particle or gamma ray hits the tube! (Note: The tube that comes with the kit is not sen…
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 10, 2016, 7:14pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/9 "2016-10-10T19:14:20Z")
Hello,
Thank you for the reply. I tried those things and I get these two errors. Please help me out. And yes I made it to the default for Serial1.
weather\_station.cpp:127:17: error: cannot convert ‘USARTSerial::available’ from type ‘int (USARTSerial::)()’ to type ‘bool’
// attach external interrupt pins to IRQ functions
weather\_station.cpp:128:40: error: invalid conversion from ‘int’ to ‘const char\*’ [-fpermissive]
attachInterrupt(RAIN, rainIRQ, FALLING);
^
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 10, 2016, 7:30pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/10 "2016-10-10T19:30:28Z")
I forgot the `()` at the end of `Serial1.available` - it should be
```cpp
while(Serial1.available())
```
And the other one needs a type cast
```cpp
Serial.write((uint8_t)Serial1.read());
```
* * *
I’ve updated the code above accordingly
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 10, 2016, 7:45pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/11 "2016-10-10T19:45:49Z")
Thanks for the quick reply.
Getting this-
weather\_station.cpp:130:11: error: ‘unit8\_t’ was not declared in this scope
delay(10000);
^
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 10, 2016, 7:47pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/12 "2016-10-10T19:47:57Z")
Because it’s `uint8_t` and not `unit8_t` 😉
But here the error message was quite clear about the reason
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 10, 2016, 10:36pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/13 "2016-10-10T22:36:55Z")
Thank you that worked, but I am still not receiving what I am expecting-
Input-
static uint32\_t ms;
String res="";
while(Serial1.available()) {
res+=(uint8\_t)Serial1.read();
}
client.publish(“TRY”, res);
if(millis()-ms \> 1000) {
ms = millis();
Serial.print(".");
}
Output-
TRY 000000000000000000000000000000000000000000000000000000000000000
Whereas I should have got-
TRY [Mightyohm.org](http://Mightyohm.org)…(it goes on)
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 11, 2016, 4:57am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/14 "2016-10-11T04:57:11Z")
The reason why I suggested `Serial.write()`ing the received data over `client.publish()`ing it was to cut out one possible cause of that issue, especially since I’m missing the info what that `client` actually is. You only revealed part of your code and not the bit that actually shows where you instantiate the `client` object.
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 14, 2016, 8:26pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/15 "2016-10-14T20:26:47Z")
I tried using serial.write() but it is giving me non-supported characters but the periods appear. What do you think I should do? Is there any other method to read from serial1?
---
### Author:  [@nrobinson2000](https://community.particle.io/u/nrobinson2000)
#### Post date: [October 14, 2016, 8:47pm UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/16 "2016-10-14T20:47:14Z")
What if you use `Serial.print()` instead?
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 15, 2016, 6:20am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/17 "2016-10-15T06:20:53Z")
`Serial.write()` gives you back what you receive, `Serial.print()` will “translate”.
So when you expect readable characters via `Serial1.read()` but get gibberish back via `Serial.write()` I’d say you’ve either set the wrong protocol parameters or your wiring is messing things up.
Can you post your current code again?
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 15, 2016, 7:09am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/18 "2016-10-15T07:09:24Z")
Serial.print() doesn’t seem to work either.
---
### Author:  [@skasat](https://community.particle.io/u/skasat)
#### Post date: [October 15, 2016, 7:10am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/19 "2016-10-15T07:10:37Z")
I checked everything again and everything looks good on the wiring part. Here is the code and different options that I have tried using. Nothing is working.
```cpp
static uint32_t ms;
while(Serial1.available()) {
Serial.write((uint8_t)Serial1.read());
}
if(millis()-ms > 1000) {
ms = millis();
Serial.print(".");
}
/*Serial1.println("TEST");
static uint32_t ms;
String res;
int cnt=0;
char chr;
while(cnt<100){
while(Serial1.available()) {
chr=Serial1.read();
res+=(String)chr;
//client.publish("TRY", res);
// Serial.println(Serial1.read());
cnt++;
}
}
client.publish("TRY", res);
res="";
if(millis()-ms > 1000) {
ms = millis();
Serial.print(".");
}*/
/*String part1,part2,part3,part4,part1val,part2val,part3val;
while (Serial1.available()){
char c= Serial1.read();
if (c=="\n"){
part1="CPS";
part1val;
part2="CPM";
part2val;
part3="uSv/hr";
part3val;
part4;
int comma=res.indexOf(",");
part1val= res.substring(comma+1,res.indexOf(", CPM"));
part2val= res.substring(res.indexOf(part2)+4,res.indexOf(part2)+6);
part3val= res.substring(res.indexOf(part3)+7,res.indexOf(part3)+11);
part4=res.substring(res.indexOf(part3)+11,res.length());
res="";
}
else{
res+=c;
}
*/
/*
char res;
int chr;
while (Serial1.available()){
res=Serial1.read();
Serial.print("--");
Serial.println(res);
//res+=(String)chr;
}
*/
/*
char storage[7];
int count=0;
String str="";
while ((str = strtok(res, ",", &res)) != "\n"){ // delimiter is the comma
storage[count]=str;
count++;
}*/
```
---
### Author:  [@ScruffR](https://community.particle.io/u/ScruffR)
#### Post date: [October 15, 2016, 7:38am UTC](https://community.particle.io/t/read-from-rx-tx-pins/26375/20 "2016-10-15T07:38:52Z")
That’s only a part of your code, I’d like to see all of it - including `setup()` and all definitions/declarations.
[Next page](https://community.particle.io/t/read-from-rx-tx-pins/26375.md?page=2)