RF Frequency for remote

[prb238]

Hi all -

Does anyone happen to know at what frequency the RF remote for the Lawnbott operates?  I am cooking up a way to pause/unpause the robot when it is in the charging station through the internet. . . .

Thanks.

Paul

[jzawacki]

I'm not sure how easy that would be to do, It really depends on the protocol used over the RF.  But, I did think of a similar idea that I never followed up on, and the RF receiver on the LB3200 side is just plugged into the serial port (the one you use to update the firmware).  So, in theory, you may be able to capture the serial communication.  If it's using a standard emulation, you may be able to create your own serial device that you can plug into the bot side and it would give you full control over your bot using whatever communication method you choose (bluetooth/wifi/etc.).  Of course, you'd have to manually design/build it all.

If you have the time and knowledge, I would suggest you try plugging the RF receiver side into your computer (with and without a null modem cable) and see if you can read the output using all the emulation options your communications program will support.  Hopefully you would be able to capture the true output from the receiver (while you press buttons on the remote).. Then, in theory, using the same emulation settings, you should be able to then connect your computer to the bot and provide that same output and the bot respond.

[RobotLady]

jzawacki, I think your suggestion is a good one.  Paul, good luck making this work...  Can't wait to hear about it!

[prb238]

Good suggestions jzawacki.  I will be playing around with this and will let you know what I find out.  While the ideas about building a new serial device sound really cool, one of the challenges is battery life to support the communication methods.  I want to try and stay away from tapping into the robot battery which would mean having another battery pack to support wifi/bluetooth or some other communication protocol.  The plus to this method is that you are building something external to the robot and then just attaching it to the existing serial port so not really modifying anything to speak of.

I don't know what others have seen, but when I have used my RF remote with the robot, I have noticed the battery on the robot drains fairly quickly.  It may be a coincidence that each time I've used it the robot has been low on battery but I've noticed this on more than one occassion.

So, my goal here is to come up with a solution that needs very little battery power to support it and still accomplishes the goal.  I have some ideas .

More to come later.

prb238

[RobotLady]

A rule of thumb in RF communications: transmitters are power hogs, receivers don't take much power.  If you have a transmitter in your solution, having it run all the time could be a significant drain on power. 

Example, if I talk on my cell phone a long time, it even gets warm in my hand.  Note how cell phone manufacturers quote talk time separately.

Anyway, keep this in mind as you figure out the details of your solution.  Having to put a receiver on the robot is likely to be an insignificant power drain.

As for the drain when you use the remote with your Lawnbott, I find it hard to believe unless the robot starts transmitting something after receiving a command from the remote.

[prb238]

Interesting - good info to know.  Well, that may steer me back to doing something with RF.  I don't think I'll be using the existing RF module on the robot since I do not know the handshake but I could use RF with a simple relay mechanism to toggle the pause button.

[prb238]

Thought I'd post an update.  SUCCESS! I've made some great progress.  I actually am now able to pause/unpause my robot from my iPhone .  I first isolated the pins on the display board that the pause button closes and then I rigged up an X10 implementation where I pass a command from my iPhone (using X10 Commander software) to my home PC, which then sends an RF X10 signal picked up by an X10 transceiver, it passes that signal to a low voltage X10 relay module which I then have connected to the robot.  When the relay closes, it simulates pressing the Pause button on the robot .  BTW - I can also turn on and turn off the robot remotely as well.

My next step is to rig up a connection mechanism similar to the way the dome nuts connect to the charging plates so I can pause/unpause the robot when it is in the charging base. This method requires no extra battery on the lawnbott - just some wires that run from the charging station into the robot display board.

Oh - and the coolest thing about this is that I can do this from anywhere I have cell phone coverage.  I am connecting to my home PC through the 3G network, not through my home network so wherever I am, I can pause.

I also have some wireless X10 cameras that I will set up - one of which will be pointed at the charging station so I can verify that I have paused the robot successfully.

Once I have this mod completed, my next step will be to follow the suggestions that jzawacki had mentioned below.  I may try to isolate the serial commands that are transmitted to the robot when the remote control is used and then come up with my own RF module or some other remote communication method so that you could issue other remote commands to the robot when it is in the yard.  This would allow you to issue a charge command to the robot if it was done with a particular zone, force it to go back to base and then come out and do the next zone.  This way the robot does not waste time in a zone when it is done mowing.

I've also got another idea but still have to do a little research to see if it is possible .

[jzawacki]

HEY!  That's cheating! 

To bad the display doesn't include direction buttons, that would be the easiest way to "hack" into it.. Good idea.

Keep me posted, as I wouldn't mind playing around with an add-on "computer" that could control the bot as well.  You can get an accelerometer dev board for $30 that would make it so you actually know when the bot is stuck.  I don't know if you saw my data on the other board, I'll dig it up and add it to my wiki. (again, feel free to create an account on the wiki and post your findings)

[RobotLady]

Check the specs on the accelerometer.  Lawnbott goes pretty slow, iy might not be enough for the accelerometer to detect it's moving.  I love the idea, hope you figure something out!

[jzawacki]

Whoops.. I guess I should have posted a link.  I already ran the test a year or so ago.. here are the results:

Accelerometer Test

[RobotLady]

Cool!  There's nothing better than a test to resolve an open question.  I agree with your comments.  A cheap part on the motherboard would not add much cost.  At least they could use it to stop the motors to reduce wear and tear.

[prb238]

Hi all -

Thought I would give an update on where I am with my pause/unpause mod.

I am in the process of machining some stainless steel plates so that I can fashion some connector plates similar to the charging plates on the garage.  I will be adding a couple of dome nuts to the robot that will be connected to wires running to the display connector to trigger pause/unpause - the dome nuts will engage the new steel plates just like the current charging nuts.

Then I'll have wires running from an X10 relay switch to the plates and when the relay switch is triggered the robot can be paused/unpaused in the base.

I've got a camera set up to view the back of the robot and I can now view the robot from wherever I am just by connecting remotely into my home PC - this will allow me to verify that the robot is responding correctly.

I've had a couple of instances just recently where I wished I had already completed this mod - It rained overnight a ton and the grass was really too wet for the robot to come out at 9am as scheduled.  So, I manually paused him and then went into the office to work.  The grass dried out pretty quickly since it was hot that day so I probably could have unpaused him by noon if I could have done so remotely and gotten an extra cutting session and charge before I got home.

[lele]

I've had a couple of instances just recently where I wished I had already completed this mod - It rained overnight a ton and the grass was really too wet for the robot to come out at 9am as scheduled.  So, I manually paused him and then went into the office to work.  The grass dried out pretty quickly since it was hot that day so I probably could have unpaused him by noon if I could have done so remotely and gotten an extra cutting session and charge before I got home.

Last season I succeeded controlling the bot from a Laptop running a stack of BlueTooth software and Zucchetti's Remote Client on top of cell emulation package, all packages freeware.
I didn't go ahead because of lacking of real world application....
Maybe you can try that as a totally software-based solution for your porblem. Detailed info shoud still be ther in the other forum.

Regards,

[jzawacki]

I'm guessing, since he mentioned RF, that he doesn't have an LB3500 series, and the LB3200 series do not have bluetooth.

[prb238]

Hi everyone -

I have finished the Pause/Unpause mod.  I decided to go back to an RF solution since running wires to the charging base and installing extra plates got too complicated once I started doing it.

So, here is what I did:

- I have an RF receiver in the robot (separate from the existing RF receiver for the remote).
- I have an extra 12v battery rated at 7.5aH in the robot in the second battery bay.  This battery is not hooked up to the robot - just to the new RF receiver.  The RF receiver pulls 8mA when sleeping and 30mA when triggered so by my calculations the battery charge should last about 30+ days.  I don't currently have a slick way to charge the battery (sealed lead acid) while in the charging base, but I will figure out a way to hook something up.
- I have an RF transmitter hooked up to an X10 relay.  When I send an On command to that relay (from my iPhone), it triggers the relay on for 1 second and turns the transmitter on for a second as well. 

This actually works anywhere in my yard - the RF signal goes about 500 feet and will cover most of my yard.  There are higher power antennas available too but I think the base antenna will work for me.

I will also be adding the ability to trigger a Charge command to force the robot back to the base.  This will be useful to force the robot home to move to another zone.

I also will be looking for a lithium ion battery that is not too expensive that is 7.5A or higher.

Fun