Automatic Litterbox Central

Are there any people interested in improving their LF?

Adding an optical sensor to set off a delay after which the LF will start a cycle should be easy to do with simple electronics.

Modifying the LF so it will only blow dry during the last cycle is a bit harder but no rocket science either. Besides preventing the smell, it will also save energy.

I'll be waiting for your detailed instructions and step-by-step photos on how to do it myself.

Well, I'm hoping to buy my LF next week. And since I'm an engineer, I will probably open it before I plug it in for the first time

I could easilly patch my unit to add the extra functionality and publish step-by-step instructions with photo's. But this will involve a soldering iron and electronic components.

Since we're all cat lovers here and only few of us are engineers, it's probably easier to design a new controller board. Anybody who could hold a screwdriver can open the unit and replace the board.

Any suggestions for extra functionality?

Sure - one very good change would be to modify the EEPROM such that one could select more than 3 cycles in a 24 hour period.

Well, if I can get away with changing the software only, I'll sure try. Though that complicates adding a cat-sensor.

But if it uses a crappy microprocessor or discrete electronics, I'll whack in a new board with a decent processor so it's just a matter of exhanging boards and connecting the sensor.

Well, I've opened up mine and I have taken a closer look.

The dryer fan is attached to the same pump as the drain pump. So it takes a lot of mechanical changes to make them work separatly. I will leave this modification to somebody else Removing the fan and puting in a fan with it's own motor shouldn't be too difficult, but I'd have to control it as well.

The good news is that the controller (called 'Wonder Box') uses an AtMel AT89C52 processor and plenty of documentation and tools are available about it. The good engineer even went through the trouble of wiring the program connector on the PCB. With a little effort I could rewrite the software and put in any features I want without modifying anything to the hardware. Nearly anybody who could hold a screwdriver could swap the processor.

I still need to investigate if the processor has a spare input I could use for a sensor. I have already put a sensor in the box and lead the start wires to the exterior of the box. But instead of connecting extra cirquitry, it would be better to use the internal processor with a software change.

WOW! I was just kidding, and I though maybe you were too. But you are really getting into it. As far as helping with the tech part .. I used to work in radio, but my expertise was limited to soldering in/out potentiometers, etc. I don't really have any electronic tech knowledge that would be helpful in reprogramming or hacking unfortunately (although I always wished I did). I'm more mechanically inclined, not electronically.

Well, the processor is socketed, so it's easy to replace.

The pins I've mentioned earlier aren't programming pins because this processor isn't in-cirquit-programming capable. I don't know what their function is then. I'll have to trace the PCB, but a spare unit would really come in handy here. But if they're regular input/output pins, they can be used to hook up the sensor to.

The processor is a 8051 family product. Damn, its design is older than I am! Luckily there is a pin compatible AVR processor with much more processing power. I'll keep you posted.

I also love my unit
I would like to add an automatic fan socket to the unit.
I am also a system (hardware based) programmer.
I have a spare unit that could be used for development.

Lets build new units (I wish)

Contact me directly if I can be of any help

Howard

Well, it would be of great help if you could reverse engineer the control unit. I just need to know what peripherals are connector to which I/O pins. In- and outputs are most likely multiplexed and there's at least one I2C bus on board for Non Volatile memory. I'd also really like to know what the small connector is used for. It looks like a programming port. You can contact me at mailto:robertdontspamme@delien.nl (leave out the obvious). I have made quite a lot of photo's of the units internals I could share with you.

Robert.

I just bought a used unit that was supposed to be opperational. All it does is click, fill with water, and run parts at random when plugged in. I pulled out the processor unit and there was nothing obvious like a chip that looked burnt. The woman who sent it to me said something about it needing to be programmed. I thought she meant programmed like some people can't program their VCR.

The point of this post is I have a unit I'll volunteer for experimentation if you can try to get the processor board opperatioinal. Just let me know if you want the entire unit or just the processor unit.

I can put together a computer, but I can't program a chip.