Using $5 Photo Frame LCD with Arduino

Other Hardware Displays
1

Ten years ago in the age of the point-and-shoot camera, everyone thought they needed a digital photo frame, now these LCDs are at thrift stores and are very inexpensive. I picked up this Coby DP730 photo frame for $4.99 and am considering integrating it into a project just by replacing its buttons with transistors or relays: previous photo, next photo, and that's pretty much it.

I understand that an Arduino will likely not be able to drive the pins for this screen natively, but I'm wondering if there'd be a way to interface this LCD with a commonly available driver board (or: somehow use the one already on this PCB?) to do more with it.

After shucking the cheap plastic frame, there's a nice 480 x 234 7" LCD in here. It is so sad to think that these components will all go an e-waste pile! Can it be reeused? What would be involved in experimenting to find a way of driving the LCD programmatically?

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2

Here's a closeup photo of the board. Looks like it's a custom ASIC that was made especially for these digital picture frames, and it has been reverse engineered pretty extensively, this looks promising, although not clear if you could get from here to an arduino: GitHub - mikeferguson/libam7xxx: fork http://git.ao2.it/libam7xxx.git, intended for packaging for Ubuntu 12.04

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3

Well demonstrated! :rofl:

Vastly too much effort I suspect. :roll_eyes:

It is vaguely similar to asking how to re-use a laptop screen with an Arduino.

I am wondering why it has a rechargeable battery in it?

Dead duck! Use it as is - with the case - or forget it. I tried using one of these as an office door sign. It did not last; I replaced it with a full size LCD monitor connected to a PC on the wall beside. Cumbersome but reliable.

I may have actually tried a second one of them in between - this was quite a long time ago. :thinking:

4

Darn okay, I was hoping maybe there'd be some standard shortcut to getting a bare LCD to do something basic without using all its pins.

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FWIW here are some photos of the LCD module. It appears to have a 26-pin ribbon cable.

5

The AOTOM chip is the FLASH memory so the other chip is the processor and LCD driver.

It's probably running Linux. I don't see any obvious test points that might be the console serial port. There are only 128 pins so it shouldn't take too long to check each one for a signal that looks like serial logging on startup. :slight_smile:

6

Thanks everyone for your replies. So, okay, new approach: I think I have an idea to use this frame just by getting the Arduino to click "next" and "previous" using the existing buttons. I presume I could use relays... but would a simple transistor work? How would I wire this up, and what sort of transistor would be needed?

7

Yes, in short that is the only plausible chance of making any use of it (other than as a photo frame) using all of the original hardware.

You first need to know how the buttons are wired. If each is simply between a pin and ground, then a 74HC4066 is simple to use. Not a relay.

Actually, a 74HC4066 will emulate a button no matter how it is wired. You need to use the same ground as the photo frame, should not be a problem as it obviously runs on 5 V.

8

OK, thank you. Confirmed as expected that shorting the two pins of the white tactile buttons causes that button to "press". The 74HC4066 certainly looks like it'd do the job although you're correct that this picture frame runs on 5V so... a thought: could I drive the pins of the button directly from my Arduino?

Here's the code suggested in that stackexchange post, the idea is to connect pin D2 through a resistor to the + side of the tactile button, and to move pin D2 through high and low states in high impedance and low impedance states (by getting the arduino to change Pin D2 from "output" to "Input" with its own pullup resistor added). The poster notes that this is effectively all that the microcontroller is looking for to decide the tactile button was pressed. The 300ms delays are just to assume the picture frame is doing a generous amount of debouncing.

For this to work, presumably Arduino and picture frame have to be on the same ground, but that's fine.

I only barely understand this... but it's wonderfully elegant! Does it make sense?

void loop() {
  pinMode(PD2, INPUT_PULLUP);
  digitalWrite(PD2, HIGH);
  delay(2000);
  pinMode(PD2, OUTPUT);
  digitalWrite(PD2, HIGH);   
  delay(300);
  pinMode(PD2, INPUT_PULLUP);
  digitalWrite(PD2, HIGH);   
  delay(300);      
  pinMode(PD2, OUTPUT);
  digitalWrite(PD2, LOW); 
  delay(300);
  pinMode(PD2, INPUT_PULLUP);
  digitalWrite(PD2, LOW);    
  delay(5000);
}