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1  Using Arduino / Displays / Re: Pervasive Displays [no power displays - e-paper] on: April 14, 2013, 05:08:02 am
More good news:

EA just released demo code for the 2.7"-EA-Board:

Demo code:

Edit: They also provide a library for the LM75A temp. sensor. Let's see if this works...
2  Using Arduino / Displays / Re: Pervasive Displays [no power displays - e-paper] on: April 06, 2013, 01:59:46 am
Good news! I just saw that the github code was updated some days ago (

There are two new examples:
1. amslide -> shows pictures that are stored on sd card using an index file stored on the card.

2. thermo -> Draw a temperature bar on the screen using Adafruit_GFX Library functions.

3  Using Arduino / Displays / Re: Pervasive Displays [no power displays - e-paper] on: April 03, 2013, 03:07:37 pm
And it worked, the temperature was around 24°C in a classroom.

But afterwards I used the code from repaper and it doesn't need any temperature.

Well the repaper-code is setting the temp fix to 25.

I tried your code, but i don't get any readings from my sensor. A look into the datasheet of the lm75b revealed that temperature is stored in two bytes. Your line of code " Wire.requestFrom(address, 1);" cannot work as it should request two bytes. Maybe you have another temp chip on your board??

I managed to squeeze three custom .xbm pictures onto my Leonardo. I'll have to get me a sd shield ( for more space ;( This means i have to multiplex the ssel pin, cause i'm running out of pins free...

For my matrix problem, I already got a NFC shield, because I'm sending data with an Android Application by the NFC transmission to Arduino, and I'm trying to display those information. And if I get a new shield, I will have problems with my chip selects.
Do you think there are no other possibilities?
Is it possible to write on an .xbm file?

I guess this needs a lot of changes in the current code. The image is stored at the beginning of the code with the PROGMEM statement. You could try to overwrite the .xbm file on runtime and see what happens. I'm not familiar with the progmem stuff - so I have to trial and error my way smiley-wink

4  Using Arduino / Displays / Re: Pervasive Displays [no power displays - e-paper] on: April 01, 2013, 07:25:05 am
I've been thinking about this problem. What about solving it by using a I2C-EEprom to store the matrix? Or use a Sdcard-shield on arduino? I think the only way of getting the necessary data for the xbm-files is to use an expansion. Arduino's mem is just too small.

I finally got the LLC from Sparkfun. Now I can try to talk to the display at last.

Currently I'm stuck with the I2C-Temperature sensor on the EA-Board. The sensor is a LM75B temp sensor and is using 3,3V on the I2C lines (so we need the Sparkfun LLC to talk to it from Arduino's 5V-I2C). The slave address of the LM75B is 1|0|0|1|A2|A1|A0 (where A2, A1, A0 can be set by the user). On my board, A2, A1, A0 are 0,0,1 - so the address is 1|0|0|1|0|0|1 (equals 73 DEC or 0x49 HEX).

But I cannot talk to the sensor. I tried with some easy code to get the values, but I don't receive anything. Anyone has more luck??
#include <Wire.h>
int t,l;
void setup()
void loop()
Wire.requestFrom(0x49, 2);
t =;
l =;      
Serial.print("temperature = ");
Serial.print("lsb = ");

As I already mentioned in my last post is that the temperature reading seems to be set to 25 in EPD.h. I'll just leave out all the temp sensor stuff and try to focus on the display.

I'll report as soon as i have more results.

@ThunderFT: Maybe you could post some code&infos on how you managed to get the display to live. I guess that would be very usefull for a lot of us smiley-wink Thnx.

EDIT: Got it to work using the gratis-master from the repaper site. It turns out that the temperature sensor is really not relevant for the code to run smiley-wink

5  Using Arduino / Displays / Re: Pervasive Displays [no power displays - e-paper] on: March 04, 2013, 03:54:43 pm
I wanted to finally power the display, but just ran out of level converters. Well - ordered a couple of 08745 Logic Level Converters and waiting for them (cause the EA-Board is using 3.3V and Arduino Leonardo supplies 5V).

Looking at the code reveals this line:
// configure temperature sensor

this will redirect to:
void S5813A_Class::begin(int input_pin) {
   pinMode(input_pin, INPUT);
   this->temperature_pin = input_pin;

As the EA has a I2C temperature sensor we need to play with those lines (remove analogReference).

After that the main loop wants to read the temperature:
int temperature =;

this will trigger:
int S5813A_Class::read() {
   return Tstart_C + ((this->readVoltage() - Vstart_uV) / Vslope_uV);

Again - as EA is using a I2C sensor we have to play withthe code. I think Arduino uses the Wire.h to communicate over I2C? But then we need the address of the temp sensor on the bus. EA writes "I2C address (0x92/0x93)" on the datasheet.

So we should be able to get the temp by modifying above code to:
Wire.beginTransmission(addr) <- (where addr is defined futher up int addr = 92;)
While(wire.available == 0) ;
int temp = Wire.receive();
return temp;

After reading the temp the code wants to run the setFactor funtion

This function is defined in EPD.h. But it looks like 25 is a fixed value here. Well maybe it works like that??
void setFactor(int temperature = 25) {
      this->factored_stage_time = this->stage_time * this->temperature_to_factor_10x(temperature) / 10;

I still have some questions concerning the code. But unless I have my logic level converters I cannot work on the display. Maybe someone can get that thing to work in the meantime.

Oh – I almost forgot! As the EA doesn’t come with a Flash chip, we'll either have to use the onboard flash, get a SD Shield or leave out the whole flash-code. At least the code is prepared if doesn’t find any flash chip (or a unsupported one):

   if (FLASH.available()) {
      Serial.println("FLASH chip detected OK");
   } else {
      Serial.println("unsupported FLASH chip");

6  Using Arduino / Displays / Re: Pervasive Displays [no power displays - e-paper] on: February 26, 2013, 01:03:36 pm

I started to compare the "EPD extension board" (EPD) with the embedded artists  E-Paper Adapter Board (EA)

Here are some of my results (not sure if i am correct, please confirm or correct me)

EPD: 5V, with serial flash, 5V tolerant, analog Temperature value
EA: 3.3V, no serial flash, not 5V tolerant, I2C Temperature sensor

Here is a table of matching pins (at least what i think). Please note, that the polarity might be different for EPD and EA.


Any luck with the above configuration? If yes, will the EA board work with the supplied example-code of

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