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Messages - Chuchaki

Pages: [1]
Android / Re: Faulty Transmissions
« on: October 23, 2016, 04:15:03 AM »
Hey, thanks for the reply. I'll try that out!
I thought this was the company's support forum. :-) This explains a lot ;-)

Android / Re: Faulty Transmissions
« on: October 22, 2016, 10:45:37 AM »
This is a support forum isn't it?

Android / Re: Faulty Transmissions
« on: August 08, 2016, 11:22:03 PM »
Honestly I would have expected a comment from the rfduino crew by now.
Is this a known error? Does it usually work and I must have faulty code?

This is quite an easy application. Every 128ms 40bytes of data. Thats really not that much...

Any comment would help. Debugging ideas, someone who got something similar working?

Android / Re: Faulty Transmissions
« on: August 03, 2016, 02:51:28 AM »
Additionally I tried to lower the sending power to minimum. Without any improvements.

I also tried different connection intervals. I have new data every 128ms. This limits the max. connection interval. All changes did not help at all.

Does anyone have an idea? I mean it must be possible to send 40Bytes every 128ms.. thats not that much...


I've read, that the BLE radio priority takes about 5-6ms and that there is a 6 Byte buffer for data. Using 9600baud this buffer overflows.

I havent looked for sources to those statements yet, but lowering the baud rate to 4800 seems to solve the issue with the faulty data.
Still this is no satisfying data rate...

Is there anyone who found a solution to for this issue?


Android / Re: RFduino to Android BLE communication weird behavior
« on: August 02, 2016, 07:16:16 AM »

I'm sorry nobody answered!
 I wanted to ask, if you found out what was wrong. I might have a similar issue myself.


Android / Faulty Transmissions
« on: August 02, 2016, 07:12:50 AM »
Hello Everybody,

I have a project, where I send data to an Android phone. I get data via the serial port to the rfduino and then send this data to the phone.
First I had 20Byte Data Chunks. I use "Serial Event" to set a Flag and then read and send the data within the main loop.

Now I have 40 Bytes of data. The Rfduino reads 40Bytes of serial data and sends it in two parts (see code). The first byte of each part is an identifier used to distunguish between the different packets.
After some successful transmissions the data becomes corrupt.

This is a basic idea of the code:

Code: [Select]

void loop() {
  if (mData)
      mData = false;
      Serial.readBytes(data, 40);
      while(!RFduinoBLE.send(&data[0], 20));
      while(!RFduinoBLE.send(&data[20], 20));   

void serialEvent(void) {
  mData = true;

I checked the serial data with a logic analyzer and there is nothing wrong with it.

I also used wireshark to check the ble transmissions. Both 20 Byte chuncks are send within the same connection interval.
The data sent by the RFduino becomes corrupt after some time.

The serial baud rate is 9600.

When I omit the second .send command and just send 20 Bytes, the problem does not occur.

I assume, that the radio interferes with the reading of the serial port. I tried to use "while(RFduinoBLE.radioActive);" before the, but I think the data is buffered before that. So this did not change anything.

I would apreciate any thoughts on this problem!
Does anyone have an idea what is going on?

Support / Re: Data Throughput Rate
« on: May 20, 2016, 11:55:38 PM »
I'll look further into it! I wont have time the next few days, but I'll report if it works and what speed I could achieve :-)


Support / Re: Data Throughput Rate
« on: May 19, 2016, 12:05:45 PM »

if I understood it right, the serialEvent is used on the RFDuino to receive a Byte. I use the RFDuino just for sending: |Arduino Due|---UART--->|RFDuino|---BLE--->|Android|.
Sorry if that was not clear. I'm not that used to express myself in english. But maybe you have another thought? Apreciate it :-)

Thanks & Greetings

Support / Re: Data Throughput Rate
« on: May 19, 2016, 06:18:05 AM »
Ok, I tried something out.
 I had an Arduino Due send five 100 Byte packets with a distance of one second in between. The RFDuino splits each packet into five and sends them with   "while (! RFduinoBLE.send(buf, 20));" . If I use a baud rate of 9600 for the UART connection, it works. If I switch to any higher baud rate, rarely all packets are received by the android phone. Mostly 2 packets.... Locking at the BLE transmission with a sniffer shows that the missing packages were never send.

For me this would mean, that a higher UART rate is not possible at all(without significant data loss).

Support / Re: Data Throughput Rate
« on: May 18, 2016, 05:26:43 AM »

thanks for the fast reply.

So basically there would be no difference ( besides the protocoll itself of course) using UART, SPI or I²C regarding the stability at certain speed?

I will try out what is possible and report my findings :-)

Thanks & Greetings

Support / Data Throughput Rate
« on: May 18, 2016, 03:21:14 AM »
Hello everyone,

I am trying to develop  a platform for the measurement of biopotentials. The RFDuino is supposed to connect the board to an Android device. One mode is the transmission of raw data, which would make it necessary to transmit 750B/s to (best case) 6kB/s.

I'm aware that the BLE Protocol depends on connection intervals, packets per connection and so on. The bulk transfer gave me 1.6 to 2 kB/s. Its not great, but its something.

Until now I wasn't aware of the 9600 Baud limit for the serial interface if used with BLE. This limits the data input to about 960 B/s, which would be just enough for one data channel.

I'm going to try using the I²C or SPI Interface for better data rates.

Does anyone have some prior experience about the use of SPI or I²C together with the BLE Stack?

Is there a similar issue with the interference?

I would appreciate any thoughts on this :-)

Thanks & Greetings

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