Hi guys, three questions.
1) How do i get very accurate odometry? IR encoders do not seem to give much accuracy, this is with regards to a micromouse by the way
2) I currently have TB6612FNG dual motor driver carrier but does it give me speed control? what would be a cheap alternative from pololu
3) Current usage is a big issue as i would be using a step up from a 1000mah lipo battery. Im not sure which step up to get. I am considering http://www.pololu.com/catalog/product/799 or http://www.sgbotic.com/index.php?target=products&product_id=70 or http://www.sgbotic.com/index.php?target=products&product_id=302 i guess the best and cheaper choice would be from the second link, any ideas?
By the way what it would power :
- http://www.pololu.com/catalog/product/993
- maybe 5 of these http://www.pololu.com/catalog/product/959
- or 6 photoresistors with ir leds to go with it( either one)
- and pic18f252
- the motor driver (not sure which one)
- odometry ( i dont what yet)
-couple of leds
thats all. Hope you guys can help. thanks!
1) IR encoders are usually
1) IR encoders are usually quite robust and accurate if installed correctly. By choosing the right part of the geartrain to measure and using an appropriate reflector/filter pattern you can have your IR encoder sampling at up to around 15kHz. Other similar options are mechanical and magnetic encoders, which pretty much do the same thing.
2) From Pololu’s website "Each of the two motor channels has two direction control pins and a speed control pin that accepts a PWM input with a frequency of up to 100 kHz."
3) 3rd option only sources up to 100mA.
2nd option is way more expensive than the other two, but it’s a good device according to the specs.
1st option can handle a good amount of current while still being reasonably efficient. Probably the best option in this case, since your motors can draw up to 360mA each at stall, which options 2 & 3 won’t be able to handle.
Good to see you telefox. If
Good to see you telefox. If u have seen, my previous attempt on a micromouse fail miserably . I decided to go step by step this time, not rushing things, just starting with basics like motor control, encoding.
However there is a question i need to ask:
4) what do you mean by installed correct? I am just using the geared motors hence the geartrain would be difficult to encode and i think that the resolution (e.g. 10pulses per round) needs to be relatively high, how do i achieve this? any ideas?
You can have the encoder
You can have the encoder work off the output shaft/wheel hub - Pololu makes a few devices that work this way. I suggest you take a look at either buying some of them, or using them as inspiration for your own encoder.
