Kosmos Build Diary

[Rocketeer13]

I thought I should start one of these, despite having already begun the robot's chassis. It's my first ever build, so please feel free to comment and critique as much as you like! My plan is to have the robot ready for the next AWS, whenever that is organised, but it will certainly be done by the end of the year. I'll post some photos this evening!

Kosmos is a front-hinged flipper, as after watching footage from several AWS events, I decided that this would be a very effective way of making good use of the low walls and open areas in the arena. The shell is 2mm Polycarbonate, and will have 1.5mm polycarb as internal supports. The drive motors are speed modified servos, and the Tx and Rx are the HobbyKing T6A. I'm still in the process of choosing the weapon servo, but I'll link the most likely option, a 2.5kg Goteck Metal Gear Servo, below, while I'm planning to try 3 AAA batteries as a power source, but will change to lipos if necessary. The name and colour scheme came from an early Russian space rocket, an idea that I think was partially inspired by bots such as Apollo, or the antweight Vostok. The aim has been to keep it relatively low budget, and I'm very pleased with the results so far!

Kosmos CAD.jpg (41.77 KiB) Viewed 17475 times

NB: The computer I'm currently on doesn't have CAD software. The current version of the chassis has a small 45° angle at the rear, like many similarly styled flippers, to allow it to roll back onto it's wheels.
More pictures of the build so far will follow this evening.

http://www.robotshop.com/uk/25kg-goteck ... servo.html

[ShootyMcExplosion]

Nice to see more front hinged flippers! Just be careful when designing the flipper that you leave enough room for the servo to fit and to allow the machine to self right, for my ant it was a very small window indeed!

[Rocketeer13]

Nice to see more front hinged flippers! Just be careful when designing the flipper that you leave enough room for the servo to fit and to allow the machine to self right, for my ant it was a very small window indeed!

I was very impressed with Sioc! It was nice to see someone else with a similar idea! Yeah, self-righting is definitely an important feature, and slightly more difficult with front-hinged designs! (hence the fins on top, to keep the flipper flat to the floor when it's overturned, which should hopefully make s/r easier - that's the plan, anyway! )

There's a bit of a delay with the photos, as I've had to order a slightly bigger battery holder: once that's sorted, I'll post them on here!

[AntRoboteer]

I've tried going with AAA batteries before and trust me, you will want to go with a lighter battery for sure. The AAAs are really heavy and restrict the design so much due to their size and weight. Also, with 3 AAAs, you will only be at 4.5V with alkaline cells or 3.6V with NiMH cells which is way lower than the specification for the servo.

I've used these batteries for quite a while: http://www.componentshop.co.uk/6v-1-4aa ... -pack.html

They are 6V, 120mAh batteries which are small, quite inexpensive and have a resonable current specification. That should do the trick nicely.

Really nice design, looking forward to seeing another front hinge flipper as they've become much rarer recently. Best of luck with the build!

[peterwaller]

They do quite a range of cell sizes and you can get them with the JST red connector see them on ebay.
http://www.ebay.co.uk/itm/4-8v-6v-120-4 ... yXTZtwbf9Q

[Rocketeer13]

They do quite a range of cell sizes and you can get them with the JST red connector see them on ebay.
http://www.ebay.co.uk/itm/4-8v-6v-120-4 ... yXTZtwbf9Q

I've tried going with AAA batteries before and trust me, you will want to go with a lighter battery for sure. The AAAs are really heavy and restrict the design so much due to their size and weight. Also, with 3 AAAs, you will only be at 4.5V with alkaline cells or 3.6V with NiMH cells which is way lower than the specification for the servo.

I've used these batteries for quite a while: http://www.componentshop.co.uk/6v-1-4aa ... -pack.html

They are 6V, 120mAh batteries which are small, quite inexpensive and have a resonable current specification. That should do the trick nicely.

Really nice design, looking forward to seeing another front hinge flipper as they've become much rarer recently. Best of luck with the build!

Thanks for that! Battery weight is definitely a concern I had with the alkaline option, but I was going to finish cutting my body panels, to get a better idea of the overall weight first, and whether or not I could use them. However my receiver arrived at the start of the week, and requires 4x AAA batteries - 6v - minimum to run. Luckily, a larger battery holder is very cheap and should arrive tomorrow, but that will almost certainly have a significant affect on the weight! I'll probably just use it to get the robot up and running for now, then look at those battery packs. I'm guessing 120mAh is all the capacity I'll need? Any idea how long that will last without a recharge?

But thanks for the encouragement! Once I get the new battery holder, I'll post a proper build update for everyone to see, as at least I'll have got the servos running by that point! (fingers crossed!)

[AntRoboteer]

Absolutely, that's great. The AAAs will be more than enough to get you started and then you can easily switch over when you like.

I've found that the 120mAh batteries tend to be good for 5-6 full length fights but with speed hacked servos and weapon probably closer to 3 fights. Of course you can just leave the battery topping up in the pit area during fights so it's no big concern. At AWS 52 one of my machines lasted all through the day (making it to the group final) only on a single 4 cell 120mAh green bar battery. You won't have any problems at all.

[Rocketeer13]

Hi everyone. Here's what I've managed to do so far. Let me know what you think!

IMG_20170921_183149947.jpg (223.6 KiB) Viewed 17337 times

IMG_20170921_182824754.jpg (198.68 KiB) Viewed 17337 times

IMG_20170921_182842894.jpg (195.88 KiB) Viewed 17337 times

I should get the rest of the body panels completed soon. I think they'll probably be mostly super-glued together, if the plastic will stick, with the top panel screwed on. My main issue at the moment is the reciever: I can't get it to power up! It might be that I need new batteries, but I suspect not, as the light has blinked at me while plugging it in, then it died again once it was properly connected. My soldering seems solid, so my guess is it'll either be a dodgy connector or a faulty transmitter (though again, I suspect not for the latter). Please feel free to leave your thoughts!

[Rocketeer13]

IMG_20170921_183052713.jpg (177.61 KiB) Viewed 17337 times

(Forgot to add a photo!)

[Occashokka]

If that's polycarb then I would advise against super glue and go for nuts and bolts