Build Diary and some questions that may appear - BW/MW

[Merkabah_PT]

Body build day 3:
Now this is starting to look like a combat robot!








(Don't mind the sandwich, working makes me hungry )

Today i also ordered my radio system, a FlySky CT6B 2.4Ghz 6-Channel Transmitter+Receiver, and a bunch of Deans Ultra Plugs (60‚/£50 with registered shipping).
(review some guy made)
http://www.youtube.com/watch?v=BbjfC2ecWt8



Cheers!

[Merkabah_PT]

I received my package today, just 1 day after making the order!

6ch 2,4Ghz FlySky Radio System, 5 Deans Ultra Plugs and some Futaba connectors.









I haven't tested the radio because i will buy the batteries support this afternoon.

Yesterday i worked a little more on the robot body, i made 2 axel supports and added 1 triangle on each side so the robot doesn't get stuck if it lands on its side.




Later today i will update this build diary again.

Cya later! :wink:

[Merkabah_PT]

Radio system tested and every thing appears to be good, still have to try the software to program the TX from the computer (elevon mixing to control the robot with just one stick).

I also finished building the H-Bridges, they don't look very good but they work great. I have to find a small plastic box to put them in.

(The two relays at the right are old ones, 5/6 years old, i was a kid and didn't know how to properly solder )







Small video of the first test drive (my smartphone sucks at filming...).


The robot is much faster than i tought it would be. It's running at 6V at the moment, but i might use a 7.2V battery because my cells haven't been used for 5/6 years and they don't hold the charge (1/1:30minutes of use and they go empty).

The robot weights around 2.2kg with the batteries and all the electronics. It can't be a beetle but i will make it an mantisweight with active weapon. Now i can because of the 6ch radio. But i will leave that for a near future, now i have to save money to buy two 6/7.2V batteries and a proper charger.

I have a 550 motor from a broken 12/18V drill, i am thinking of using it to power a vertical spinning bar/disk.
Maybe something like this:

(I know the disk teeth are wrong )

Cya.

[Merkabah_PT]

So, i forgot that i should put a protective diode on my relays coils to protect the servo pcb/receiver.
My circuits look like these, how should i install the diodes? Any help? I don't want to destroy my receiver.


(It was drawn very quickly on paint)

[daliad100]

Reverse bias parallel to the coils (backwards across the coils)

[Merkabah_PT]

Like this?



The two relays are connect to a servo pcb, instead of the servo motor, and the two wires change polarity. Will the pcb/receiver be protected this way?

I have seen some people from RC forums doing this exact same schematic (without the protection diodes on the coils) without any problems. May be the protection diode only works/is requiered when using microprocessors and such? I don't see how the diode will protect the pcb on a changing polarity circuit like this...

[Merkabah_PT]

Tomorrow my 7.2v 1800mah battery should arrive, so i am checking my wiring. Currently its done with 22awg (0.644mm) wire, but it looks to thin for me. I was thinking of replacing all the wires with 18awg (1.024mm) i have.
Holding the wheel on the motors they pull about 10A each, will wiring be fine with the 22awg or should i really replace with 18awg?

Every thing i find on the web is different from site to site, some say 22awg only handles 1A, other say it handles 7A others say it handles around 14A.

You guys have personal experience, so i am asking you.

[Bodge Job]

i use something overly thick (after all my wiring melted at an event) , i use 2 mm wire (i dont know the gauge) but if its only 10 amps, the 1mm would probably do as its a lighter weight robot

[Merkabah_PT]

So, today my new battery should have arrived, but the mailman didn't ring my appartement bell and forgot to leave the warning for me to withdraw my package at the postoffice. Tommorow morning i will go to the postoffice with my delivery code and try to withdraw it, but i expect it to be a pain in the a**, as portuguese workers tend to over complicate things...

Today i replaced the wiring with 18awg just to be shure nothing melts and couses a short-circuit. Better off this way.

My build it on standby until i get my battery, and 3 days doing nothing is killing me.

After this first fase of building Primogenito as a wedge robot, i will have to save some money to get 2 pulleys, a belt and a 12v battery to power the weapon (vertical spinning bar). After that i will start to design and build the upgrade so i can have some fun with the robot destroying things.

Cheers.

[Merkabah_PT]

Phase one at 95%!

Primogenito is as compact as it could be, it was almost impossible to fit the receiver batteries. I am considering making a BEC so i only use the main battery and it's much smaller than 4AA batteries. What amperage you guys think i should chose on a voltage regulater to build the BEC? 1, 2 or 3amps?

Just need to make the main battery removable link, program the elevon mising and sand/paint the steel bottom and wedge (their surface is rusting pretty bad).

My father showed me a trick to remove rust using lemon juice, but i will sand the metal so that the paint will adhere better.

I was going to make a small test drive video, but batteries only come with a little charge and it died on me...
I will leave you with some photos (this time they were taken with a digital camera ):