Hybred Boe Bot

Crazyrabbit · 2011-09-06 03:43

I finally completed my new Boe Bot. It was built up from just the body. I chose the Boe Bot because it is small and easy to add things without drilling holes. It is getting quite heavy though with 2 battery supplys and mabe 3 in the near future. I am planning on piling up the electronics. Here is a video with just the ping. It works OK but can see it will need more traction because of the weight. I am already using higher power servos. Here is a video of a trial run http://www.youtube.com/watch?v=VoYSpf0Inwo

Here is a video with some improvements I added to the bot. One was adding a speaker and volume control and the other was upgrading the wheels. Wheels do make a big difference. Haven't got to hacking the program yet.

http://www.youtube.com/watch?v=9kc3d8v40po

PJAllen · 2011-09-06 05:58

I was using a scanning/sweeping Ping as you are here, which has its evident shortcomings.
That's a numbers game, if you will, not infallible - a lot depends upon timing (clunk.)
My thinking, now, is to use IR for obstacle avoidance and scanning/sweeping the Ping to figure the next direction.

Please tell me more about your "higher power servos".

zappman · 2011-09-06 07:46

That is a great little custom "Hybred Boe Bot". Can't wait to see what you do with it next.

Bill Henning · 2011-09-06 08:03

Nice breadboard based bot!

The boe-bot chassis is a great platform for experimentation.

Crazyrabbit wrote: »

I finally completed my new Boe Bot. It was built up from just the body. I chose the Boe Bot because it is small and easy to add things without drilling homes. It is getting quite heavy though with 2 battery supplys and mabe 3 in the near future. I am planning on piling up the electronics. Here is a video with just the ping. It works OK but can see it will need more traction because of the weight. I am already using higher power servos. Here is a video of a trial run

http://www.youtube.com/watch?v=VoYSpf0Inwo

Bill Henning · 2011-09-06 08:06

I agree!

I tend to add (at a minimum) left & right front "virtual bumpers" (reflective IR sensors) good to at least 10cm as I'd hate for robots to run into something they just missed in the last sweep...

PJ Allen wrote: »

I was using a scanning/sweeping Ping as you are here, which has its evident shortcomings.
That's a numbers game, if you will, not infallible - a lot depends upon timing (clunk.)
My thinking, now, is to use IR for obstacle avoidance and scanning/sweeping the Ping to figure the next direction.

Please tell me more about your "higher power servos".

erco · 2011-09-06 09:00

Nice Bot, Crazyrabbit! Looks like it's struggling some on the turns due to to excess weight on the idler wheel since you added weight. If you shift weight forward onto the drive wheels, it will turn better. But keep the CG low, or it will tip forward when it decelerates. You might add another idler in front. Also, changing the idler ball to a real caster would help out on the turns. Keep it up!

Crazyrabbit · 2011-09-06 14:43

I do have plans. As far as shifting weight, where? It has a 6V ni cad pack on the bottom replacing the 4 pack of regular batteries. It also has a 6V ham radio battery for the electronics. Wait until I add a AA x 6 (7.2v) battery pack. It fits nicely on the aluminium bracket with out any mounting hardware. I agree that IR is needed to help with the ping as you can see with my other robots. I just got started on this one. As far as the servos, I am using cheap chinese servos modified to continious motion. They have ball bearings and double the torque of the Parallax version. A bit faster too. Can't wait to see this Boe run with 7.2V motor supply like my other bots, but one step at a time. I have alot of ideas with a shortage of time at the moment. If you want more details on the servos, contact me at Crazy Rabbit's Home Robotics on Facebook. I like Parallax and their forum alot and don't want to break any of their rules.

PJAllen · 2011-09-06 17:18

I think it's cool to link to the servos: I asked, they're part of your project, you're not running down Parallax and they don't have "higher power servos" anyway.
[I go to Parallax products first and foremost, nobody plugs the organisation more than I do.]

Publison · 2011-09-06 18:23

Yes, please..link to servo.

Spelling Police notice. Hybred should be Hybrid.

Organisation was going to be put on the missed spelling bee also, until i found:

Greek-derived spellings

[edit]-ise, -ize (-isation, -ization)
See also: Oxford spelling
American and Canadian[33] spelling accepts only -ize endings in most cases, such as organize, realize, and recognize.[34] British usage is split between both -ize and -ise (organize / organise, realize / realise, recognize / recognise),[34] and the ratio between -ise and -ize stands at 3:2 in the British National Corpus.[35] In Australia and New Zealand -ise spellings strongly prevail: the -ise form is preferred in Australian English at a ratio of about 3:1 according to the Macquarie Dictionary.
Worldwide, -ize endings prevail in scientific writing and are commonly used by many international organizations, such as the ISO and the WHO. The European Union switched from -ize to -ise some years ago in its English language publications, and this resulted in the coexistence of the -ize spelling in older legislative acts and the -ise spelling in more recent ones. Proofreaders at the EU's Publications Office ensure consistent spelling in official publications such as the Official Journal (where legislation and other official documents are published), but the -ize spelling may be found in other documents.
The same pattern applies to derivatives and inflections such as colonisation/colonization.
[edit]British usage
British English using -ize is known as Oxford spelling, and is used in publications of the Oxford University Press, most notably the Oxford English Dictionary. It can be identified using the registered IANA language tag en-GB-oed. The OED lists the -ise form separately, as "a frequent spelling of -IZE", and refuses to list the -ise spellings even as alternatives in the individual entries for words such as realize.[36] It firmly deprecates usage of -ise for words of Greek origin, stating, "[T]he suffix..., whatever the element to which it is added, is in its origin the Greek -ιζειν, Latin -izāre; and, as the pronunciation is also with z, there is no reason why in English the special French spelling in -iser should be followed, in opposition to that which is at once etymological and phonetic." It maintains "... some have used the spelling -ise in English, as in French, for all these words, and some prefer -ise in words formed in French or English from Latin elements, retaining -ize for those of Greek composition."[37] Noah Webster rejected -ise for the same reasons.[38]
The Cambridge University Press, on the other hand, has long favoured -ise,[39] as do some other references, including Fowler's Modern English Usage.[39]
Perhaps as a reaction to the ascendancy of American spelling, the -ize spelling is often incorrectly viewed in Britain as an Americanism, and -ise is more commonly used in the UK mass media and newspapers,[34] including The Times, The Daily Telegraph and The Economist. Meanwhile, -ize is used in many British-based academic publications, such as Nature, the Biochemical Journal and The Times Literary Supplement.
Exceptions
Some verbs ending in -ize or -ise do not derive from Greek -ιζειν, and their endings are therefore not interchangeable:
Some words take the -z- form exclusively, for instance capsize, seize (except in the legal phrase to be seised of/to stand seised to), size and prize (only in the "appraise" sense)
Others take only -s-: advertise, advise, apprise, arise, circumcise, comprise, compromise, demise, despise, devise, disguise, excise, exercise, franchise, guise, improvise, incise, merchandise (noun), revise, rise, supervise, surmise, surprise, televise, and wise.
One special case is the verb prise (meaning to force or lever), which is spelled prize in the US[40] and prise everywhere else,[41] including Canada,[42] although in North American English it is almost always replaced by pry, a back-formation from or alteration of prise.[43]

I guess it's the Aussie.

I learned sumthin' new today. (That's correct spelling for some of our under funded public schools)

GordonMcComb · 2011-09-06 19:36

British spelling. They also think color has a 'u' in it, and while is something that ends in 'st' (as in whilst).

Now you know why the Colonists broke away from England.

-- Gordon

PJAllen · 2011-09-07 05:57

It's while or whilst, but only when they're used as conjunctions. When your friend is late you wouldn't say, "No fear, he'll be along in a whilst."

Till or until, toward or towards, 6 of one and a half dozen of the other.

[Waiting for that servo link. Anyway.]

Crazyrabbit · 2011-09-12 03:14

I just added a new video with bigger wheels. Running better. See original post.

PJAllen · 2011-09-12 15:39

Clunk! (X2)

GordonMcComb · 2011-09-12 16:55

Cool looking bot. I watched the video whilst programming my own FrankenBoe-Bot.

You may want to think about adding this sensor on the turret with the Ping:

http://www.pololu.com/catalog/product/1134

(I'm hoping Parallax makes something similar, but for now Pololu is a good low-cost source.)

These are *digital* distance sensors, set to trigger on proximity at 4" or closer. Output goes LOW if there's an object within this distance.

Ultrasonic sensors are not very reliable if the robot or sensor is in motion. This is due to the dispersion of the sound waves and Doppler effects. The IR sensor is immune to these, so you can use it as a backup warning. You don't have to rely solely on the ultrasonic.

They're also handy because they have an internal 300+ Hz refresh rate, so they react to change much faster. You can even use this feature to slow down the samples from the Ping, and thus save some current consumption.

-- Gordon

zappman · 2011-09-12 17:21

GordonMcComb wrote: »

You may want to think about adding this sensor on the turret with the Ping:

http://www.pololu.com/catalog/product/1134

(I'm hoping Parallax makes something similar, but for now Pololu is a good low-cost source.)

These are *digital* distance sensors, set to trigger on proximity at 4" or closer. Output goes LOW if there's an object within this distance.

-- Gordon

Hi Gordon,

I am also working on a "FrankenBoe-Bot". I purchased four of the sensors to add to my BOT. The thing I noticed is that they don't seem to be able to detect black. I powered one up and held it up to different objects, there is a red light on the board that turns on when the sensor detects an object. When I held the sensor near a black plastic box, the sensor would not come on.

Regards,

zappman

GordonMcComb · 2011-09-12 17:27

That's correct; anything that absorbs IR will not yield a result. (Black conductive foam soaks up IR light almost completely, for example.)

Hopefully you don't have black baseboards in your house! Otherwise, you'll need to coordinate the readings with the ultrasonic -- that's what sensor fusion is for, after all -- and cross your fingers more tightly.

-- Gordon

PJAllen · 2011-09-12 17:31

Black baseboards... would that be cool or what?

Crazyrabbit · 2011-09-13 02:10

No IR detects black. I have some home made IR sensors that were pretty much right out of the parallax boe book. I am just getting started. You can see them on my Mini Hightower bot video. I used 3 with no Ping and it got around pretty fast and they are ajustable. I made an external ocillator to save on IO pins, I also have a few home made short range sensors, but they would need a comparitor circuit to work better. R & D still in progress. What I lack in programming, I make up with electronics. lol

http://www.youtube.com/watch?v=NWgUt0lFtEk&feature=mfu_in_order&list=UL

Hybred Boe Bot

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