This is only if you are using encoders on your wheels that have a very high count per revolution amount really. For SLAM to work for me the way I want it to, I had to make some logic divide by 2 circuits so that the count wouldn't be so high.

Unless you are in this same situation, no need to purchase the divide by 2 circuits. If you are, they can help a lot. The other 2 parts could be helpful though.

So I do need encoders but not sure what to use because I am using the same wheels and motor as Richard r and BHouston . Without encoders. Maybe You or RichardR could suggest what I should use?

My wheels are7" and I really can't go below 6" for clearance. Thanks

What kind of motors are you using?

I will have to look tonight currently at work right now

@David, here is the link to the motors and wheels I currently have.
http://www.ebay.com/itm/291057616929?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It looks like there is a shaft on the back of the motor but unless I had one, I don't know what it would take to add an encoder to the back of the motor. The other option is to add it at the wheel end of the motor. Without specs on the motor, I wouldn't be able to tell you if you would probably need a logic divider or not.

Here is what I mean...

If you had a motor that was geared 200:1 and you had an encoder on the back shaft of the motor that was a 500 count encoder, you would get 100,000 counts or ticks per revolution of the wheel.

If the encoder were a 100 count encoder and it were on the wheel end of the motor, you would get 100 counts or ticks per revolution.

The gear box and the placement of the encoder in relation to the gearbox has a lot to do with the level of detail by the number of ticks per revolution.

The issue comes in if the gearbox is say 127:1 and your encoder is before the gearbox, causing the encoder to spin 127 times per revolution of the wheel. This also gives you very accurate movement though.

Here is a photo of a sample of one of the boards. There is a modification to them to allow index to also be used, and will have thicker leads and less space on the sides, but this will give you an idea of what you would get to solve the high encoder count issue for these motors and these kangaroo.

I will start taking orders for these. Just send me an email. My email address in on my profile. They will be $8.00 each. If I already have an email from you then I already have you down for the number that you ordered. It will be about 2 weeks before I can have these made and shipped out.

This is a first come, first served deal. There will only be 20 available in the first order, of which 10 are still available.

Payment will be available through Paypal and the details will be handled through email for any orders.

i was able to squeeze 2 more of these logic dividers onto my board design. Because of this there will be 8 more of these available and it reduced the cost to $8.00 per board.

The order for the boards will go in tomorrow. It will take about a week for me to receive these boards, and then about a week to make and test them before shipping.

I will update this thread with the current status as I know more.

Shipping inside the US will be done through USPS. Outside of US, I will have to see who has the best rate available. I know some have different shipping methods that they prefer. We can discuss the rates and all through email when the orders are ready to ship.

Payment will be due when these are complete and I have tested them and know that each one is working correctly.

I will provide post headers but wont solder them so that you have the option of using something else in this location. If you want me to go ahead and solder the post headers onto the board, just let me know.

Thanks David