DerpBOT Arlo chassis

Shocken_Awe

Hello everyone today marks day... -1 of my new robotics project, DerpBOT which will be based off the Arlo chassis. About three years ago I discovered Parallax and played around with the BOE Bot, from there I tried using the Propeller microcontroller. That did not go so well, SPIN and I did not agree well. When I saw that the Prop controller now uses C I picked it back up and found it to my liking. Now I am starting on a new project. once I start getting my components in I will make sure to take pictures and document the building and programming. Already have a project board and two motor controllers shipping, and have 3 PING))) sensors sitting in a box from a few years back. Heres to a new year with a new toy!

Shocken_Awe

Got my activity board, HB-25 controllers, and Parallax was feeling Christmasy and threw in an RGB LED module for free, thanks guys! Now to get started with some practice programs.

Shocken_Awe

Picture of the circuit in action

the C version of the code for it DifferancePING(((.c
This is the first test circuit and program. Its fairly simple, it just polls two PING((( sensors, gives distance to terminal and compares the distances measured. If the same it will also emit a tone. Found I had to add pause commands between the two sensor polls to keep sensor 1 from hearing sensor 2 and another pause after to get accurate longer range measurements, but all in all its only a 175 millisecond pause for the entire script, more than fast enough for what I plan to use this for. These sensors will be my primary short range distance reading and be part of a directional decision tree. once I get more of the Arlo chassis I will program these to detect edges of walls/door frames/etc. and decide if the robot can continue forward just by turning to the side alittle. I hope the code is useful the forums would not take the .side format. If not its a simple code and I can type it out longform, not sure what I will do once the code starts growing though.

dgately

Shocken_Awe,

I assume that you are using SimpleIDE for your project (if not, please ignore me)...

In SimpleIDE's Project menu there is the "Zip" item. Once you have your code compiling, you can use the Zip command to archive a copy of your whole project as a .zip file, which can be easily transported through the "inter webs" i.e. attached to the forum thread!


dgately

Shocken_Awe

I am useing SimpleIDE (I probably should have mentioned that) and that is a very handy feature. Thanks dgately!
So now here is the more usable ZIP file of my simple test program: DifferancePING(((.zip

Shocken_Awe

I just got the Arlo base and power distribution board and have ran into a small problem. I hooked up my motor controllers and Propeller activity board and ran power from a large 12 battery I have laying around. The distribution board seems to be working fine, I get 12,6.5, and 5 volts out of where I should. However, when I connect the activity board to either 6.5 volt supply it turns on fine (actually it turns on and lights setting 1 light), but I only get 3.2 volts off of the servo headers. I checked the 5volt supply and I get a steady 5 volts from there. Its only the headers. Interned moving the jumper between the two positions but that does nothing. I do have 8.2 ohms of resistance on the wire and plug connecting þe board to power, hopefully that's the issue, I plan to redo that anyway. Anyway! I'll have pictures of my progress later today, thanks!

Duane Degn

The switch on the Activity Board has two positions. Did you move the switch to the "full on" position? Full on is the position furthest from off.

BTW, see my comments in this thread about using the distribution board while also using USB.

Shocken_Awe

I tried all three positions even off, and the board still turns on glowing the position one led and only supplying the 3.2 volts to the servo headers. Also thanks for the link, that is going to save headache later on!

Duane Degn

Shocken_Awe wrote: »

I tried all three positions even off, and the board still turns on glowing the position one led and only supplying the 3.2 volts to the servo headers. Also thanks for the link, that is going to save headache later on!

Are you measuring the center pin on the headers?

Shocken_Awe

Duane Degn wrote: »

Are you measuring the center pin on the headers?

Yes the center (V+) and the lower (gnd) pins.
Glad I forgot to send this...I belive I found the problem. I just tried measuring voltages again and my battery only reads 9 volts, I feel abit silly but I'm sure it wont be the last time I chase ghosts.

Shocken_Awe

Ok! I got the Arlo base and power distribution board and attached my motor controllers and activity board to it all. That and some wire and heat shrink and its starting to look like... a Frisbee. I actually love the look and motor controller placement, almost like little jets on the back. Sadly the base came abit scratched up on the bottom and top, thankfully once I get everything set up I was planning to paint the base anyway. It still does not come with the standoffs for the control board, so I made due with rubber feet and a few spare screws, seems to hold just fine. Also.... I think I'm going to need a bigger pony to pose the robot with now.

Shocken_Awe

My god, already nearly 4 years have past, and Parallax has updated EVERYTHING but through all that I finally have an update:



You will notice I abandoned the Arlo chassis, I never could afford the wheel and motor set but was given an old Roomba to mess around with and remembered this project. I never did figure out why I am not getting proper voltage at the servo headers but took a risk and ran a wire from the 5 volt output of the Power Dist board and am using that to back feed the header which is working just fine. So for only have a few test programs checking the PING))) sensors, motor controlers, and LCD which all seem to work just find after 4 years of collecting dust on a shelf. Hopefully now I can actually get this thing up, running, and scaring the cats!

erco

Welcome home, Shocken_Awe! Good to hear you're back in business. Hope to see more of your build soon. How about a figure 8? You may be our first Roomba.

https://forums.parallax.com/discussion/138125/erco-s-figure-eight-challenge

Shocken_Awe

erco wrote: »

Welcome home, Shocken_Awe! Good to hear you're back in business. Hope to see more of your build soon. How about a figure 8? You may be our first Roomba.

I will have to try that after I get it up and running.
Also its continuing to throw little issues at me. The Roomba motors have non-quadratic motor encoders based on hall effect sensors and I am getting signals from them but am not having luck turning it into something useful, I probably just need to toy with it more but wondering if anyone has any idea how to get usable ticks, the encoders pull low on each pulse and give 508.8 (yay even numbers) for each wheel rotation. I got close using a variable in the X=X+1 format but most of the time the variable will continue counting up even though the wheel is stopped. I'm just using BlockyProp at the moment as I need to relearn SimpleIDE and I'm just doing rough test programs atm.

Shocken_Awe

Here is a test of a simple program I threw together, very far from perfect but all the hardware seems to be working, other than encoders.

https://youtube.com/watch?v=Qw-pYkKygXE