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Build Log - Bread Dead Redemption (FW) - First Build.

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  • #16
    Definitely winging it, my CAD skills leave a lot to be desired. In that sense, I'm quite glad I'm using a toaster as it gives me a physical baseline to start with. It's tough to get an idea of what I want, because I want to make it as strong as possible, but also want to avoid it looking like a HDPE box with a surprise toaster center, like the worst kinder egg ever made.

    My options in my head at the moment are as follows:

    Option 1: Cut the bottom half of the sides off the toaster to put the wheels through, then build a wider base out of the HDPE and build wheelguards and armour supported on that. The toaster itself is probably >1mm stainless steel, so I would need to reinforce the inside of the toaster as this wouldn't support things being mounted to it very well.

    Option 2: Attempt to fit all the motors and electrics inside the toaster by ditching the drill chucks/casing and getting some custom motor mounts made (probably advisable in the long term), but could be a tight squeeze regardless. From there mounting the HDPE to the outside, but I'm considering rubber washers (?) on the bolts in between to act as a shock absorber. Again, inside the toaster would need reinforcing to "sandwich" the panels together. Not sure how practical or effective this would be, so I'm leaning toward option 1 at the moment.

    The back panel with all the toaster buttons needs to be visible in both options. It still needs to look like a toaster, after all. I'm considering getting some 10mm polycarb for this as it is transparent. Any leftovers could also be used for the internal reinforcement mentioned above, saving space compared to using the 20mm HDPE. However, I've read in a couple of places that polycarb isn't suitable armour anymore, but haven't listed why. The front panel will have the dustpan mounted to it, either to HDPE, polycarb or both.


    That's where I'm at at the moment! Not sure if what I've written makes any sense whatsoever, but it makes sense in my head at least. The HDPE has arrived and is in the garage waiting to meet the bandsaw. Just need to decide on one of the above options and go for it.


    Also, side note: I also put the above test videos on my Instagram and got likes from Daniel Freitas of Riobotz, Will Bales of Hypershock and Calvin Iba from Mad Catter. Not particularly relevant to the build, but I'm still having a massive fanboy moment about this and need to express it to people who will know what I'm talking about . I've only been building for two weeks and the support and enthusiasm I've had from family, friends and you guys on here has been so encouraging. I'm absolutely loving it so far. Thank you so much.

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    • #17
      I think I'd go for option 1. It would look less like a toaster overall but way more durable.

      However, I've read in a couple of places that polycarb isn't suitable armour anymore, but haven't listed why.
      Mounted incorrectly, polycarbonate can be brittle but I disagree that it is not suitable armour mounted right. I used a 10mm polycarbonate wedge on my old Middleweight and stood up to a lot though I doubled up on the leading edge to 20mm for increased durabilitity. Jibril uses polycarbonate as its top armour as well, hasn't really let me down yet.

      Armour smarter, not harder etc etc.

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      • #18
        I'm thinking Option 1 too, Lucy. I've also changed my mind on winging the design, Toaster CAD is underway!

        Toaster CAD.png

        Good to know about the Polycarbonate, cheers! When you say mounted correctly/incorrectly, what would be the correct way to mount it? I know it gets less durable when you start drilling holes in it, but that seems unavoidable in building robots?

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        • #19
          When I say mount it, I mean the angles. Polycarbonate, in my experience, doesn't stand up well when the leading edge is exposed. Spinners tend to cause it to shatter. You are correct that when drilling holes, the area around it does become less resistant. I tend to use large roofing bolts to cover the holes to offer more resistance. Comes down to planning really as to where the holes go and what reinforcement is needed.

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          • #20
            Good to know, cheers! I'll get some polycarb and aim to attach it to the base to avoid any catch points for potential spinners.

            Gradually getting the hang of CAD. It doesn't look massively glamorous, but it tells me all I need to know so far.

            Toaster.JPG
            Toaster 2.JPG
            Toaster 3.JPG

            I now know what size panels I need to cut from this, so that will be the next step. I've also discovered that the thickness of the base panel may not give enough ground clearance with the wheels that I have. They are quite hard plastic anyway, so attaching some bits of rubber tire could help give extra grip and ground clearance.

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            • #21
              If you need some custom motor mounts for those Aldi motors, I’m happy to assist with that. I sell the mounts for Argos and black decker motors too.

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              • #22
                Originally posted by Mr Manuva27 View Post
                Good to know, cheers! I'll get some polycarb and aim to attach it to the base to avoid any catch points for potential spinners.

                Gradually getting the hang of CAD. It doesn't look massively glamorous, but it tells me all I need to know so far.

                [ATTACH=CONFIG]9139[/ATTACH]
                [ATTACH=CONFIG]9140[/ATTACH]
                [ATTACH=CONFIG]9141[/ATTACH]

                I now know what size panels I need to cut from this, so that will be the next step. I've also discovered that the thickness of the base panel may not give enough ground clearance with the wheels that I have. They are quite hard plastic anyway, so attaching some bits of rubber tire could help give extra grip and ground clearance.
                Good work. Even a very basic CAD model is really useful I find, just to see how things will roughly fit together and how big various bits need to be. I don't think I could make anything other than boxes without CAD.

                Starting off with hard wheels/low ground clearance is a good bet, you can always try it out and add the bike tyre afterwards!

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                • #23
                  Not updated for a while, but work is still ongoing, just slowed down a bit! I would have been pushed for time anyway, but life stuff means that I won't be able to make the October Robodojo, even as a spectator. That means it is full steam ahead for the December Robodojo and Manchester Extreme Robots events!

                  The HDPE and Polycarb have arrived and the HDPE is all marked up with panel sizes from the CAD ready for cutting. Unfortunately, the garage is a proper mess right now, so I'm waiting to get space to mount the bandsaw so I can use it safely. Before I start constructing, I'll be working to remove the chucks from the drill motors to make sure everything still fits (Nat, I will likely be in contact when I've done this to discuss ordering mounts from you ).

                  I've also got my LEDs for power light and decoration. I've gone for orange, so it will look like it is toasting while in battle (although I am concerned it may be against the rules as it may look like the robot is constantly on fire? I could always go with red if needed, they weren't exactly expensive). Aside from that, I'm trying to get my head around LiPo batteries and what I require. I've seen that 3S is quite common for 2WD on the Argos motors, but with my motors being 20V, I'm not sure if that still applies?
                  Last edited by ; 22 September 2019, 19:54.

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                  • #24
                    I've also got my LEDs for power light and decoration. I've gone for orange, so it will look like it is toasting while in battle (although I am concerned it may be against the rules as it may look like the robot is constantly on fire? I could always go with red if needed, they weren't exactly expensive).
                    Orange is fine. The FRA rules specifically state that it has to be a solid, contrasting colour to the rest of the robot (rule 6.4).

                    Aside from that, I'm trying to get my head around LiPo batteries and what I require. I've seen that 3S is quite common for 2WD on the Argos motors, but with my motors being 20V, I'm not sure if that still applies?
                    LiPo cells are 3.7v nominal, so 3*3.7 = 11.1v. If your motors are rated for 20V, I'd recommend 5 or 6S (18.5 or 22.2v) LiPo in that case but I would think would still move with 3S, just be underpowered in that case.

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                    • #25
                      I've just checked the prices of 5-6S LiPo and they seem expensive for a first build. I reckon it would still move on a 3S, it has been running pretty well on an 12V drill battery in testing.

                      Considering that I only bought the 20V motors because they were cheap in Aldi and Argos only had one drill in stock at the time, I may ditch them for some Argos motors and run on a 3S. I already have one Argos 12V motor in reserve, so would just need one more. They would be easier to replace in the inevitable event that they break and it would be less hassle to get mounts made too.

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                      • #26
                        Probably a good plan - it would be a real pain if one of your Aldi motors breaks and they've stopped selling them. Seems like the Argos ones are here to stay.

                        The other advantage of 12v is you can use more hobby RC ESCs, which tend to cap out at 3 or 4s. Note that the 12v motors will run quite safely, and a bit faster, on 4s, though 3s is fine. I've find two drill motors is more than powerful enough though, so it's probably a matter of whatever is easier to get hold of and fit in your machine.

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                        • #27
                          In my experience, RC Hobby ESCs (such as the "320A" types you see floating about on eBay) that tend to not be very robust. The Honey Badger 1.0 used to use them for both it's weapon and drive and it was forever blowing them up on 12V 1.2aH SLA batteries. I really should rebuild that one day.

                          That being said, they can work in Beetleweights (The Honey Badger 4.0 uses them) so I guess it depends on the load through them and what application they are being used for.
                          Last edited by Ocracoke; 24 September 2019, 11:03.

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                          • #28
                            So it has been a few weeks, but the work has not stopped! I hope everyone had a great time at Robodojo on Sunday, I definitely wished I was there.

                            After a relaxing holiday in Center Parcs last week, I found myself with 4 days off to do nothing but work on the robot. Perhaps you may want to put the kettle on, this could be a long one, we have a lot to catch up!

                            Pre-Holiday

                            A few bits sorted before I went away. I bought some 12v Argos drills and ordered some motor mounts from RoboteerNat. Also, having seen that some events require a "Team Shirt", I got on Spreadshirt and started designing a jacket. I'm really pleased with how it turned out :

                            IMG_20191011_185258.jpg

                            IMG_20191011_185328.jpg

                            Saturday

                            Plan for Saturday was to strip down and modify the drill motors and see if everything fits on the HDPE baseplate I measured out. Unfortunately this was scuppered by the drill chuck, with the reverse thread screws not budging no matter how much I tried. I wasn't too happy with the situation. After sending the below photo to my Dad, he offered to lend me his impact driver.

                            IMG-20191012-WA0001.jpg

                            Determined not to let a day be ruined by a single screw, I grabbed the cutting table and a hacksaw and set to work cutting the HDPE panels outside, as the weather was lovely. Due to a lack of space in the garage, we still hadn't mounted the bandsaw. After about an hour, my Mum's boyfriend Roger came to see how I was getting on.
                            "Isn't it a bit of a waste doing this by hand if you have a bandsaw?" he questions. "Do you really think we will find enough space in there to mount a bandsaw before the start of December?" I reply, gesturing broadly to the bulging garage.

                            What resulted from that conversation is probably one of the most absurd and potentially dangerous contraptions that Rog and I have ever rigged up, much to the horror of my Mum:

                            IMG_20191012_165158.jpg

                            Portable Bandsaw! With the bandsaw securely mounted to the cutting table, it made short work of the rest of the panels. Time to see if my CAD designs and measurements were accurate!

                            IMG_20191012_171919.jpg

                            Oh, heck.

                            Not so much slightly out, more like miles away. With the light fading, I had two options. Either be sensible, pack up and go inside, or make a rough estimate of how much to cut it further and just go for it. Naturally, I went for option 2.

                            IMG_20191012_175526.jpgIMG_20191012_175513.jpg

                            RESULT! A tad rough around the edges, but it all fits! Pleased with my progress, I packed up for the day.


                            Sunday

                            Sunday progress delayed due to collecting the impact driver, which made short work of the screws in the drill chucks. One of the 3 drills I had dismantled no problem. The other two were a different story. Unscrewing the clutch changer on both drills released the spring, pushing the chuck up and releasing the ball bearings underneath, jamming them both.

                            I grabbed a hacksaw and started slicing away at one of them to try and free the ball bearings. The result was no different, any twists to the chuck just turned the drill shaft. We were back to this again:

                            IMG_20191013_202449.jpg

                            After attempting several different tactics, I wedged an M8 bolt in to the drill chuck and attached the impact driver to try and shock it free. No luck. The final straw came when I lodged a screwdriver in the gearbox to try and lock it, but just shredded the gears and ruined the gearbox. Oh well.

                            Lesson learned: When dismantling a drill, remove the chuck first.


                            Monday


                            Fresh start on Monday. Attempted the M8 bolt in the chuck/impact driver tactic with the third drill that I hadn't butchered with a hacksaw. Success! The ball bearings flew everywhere, but I wasn't bothered by this point, just relieved. I locked the clutch off on both drills with grub screws and fitted the mounts. Ready for use!

                            IMG_20191014_153414.jpg


                            Tuesday

                            Today consisted of a trip to Halfords to buy a bike tyre and some safety glasses. From the information that Nat gave me about the mounts, it would give me precisely 0mm of ground clearance with 100mm wheels and a 20mm base. The bike tyre should give extra grip and clearance from the arena floor.

                            I cut the polycarbonate on the bandsaw for the front and back panels and then set about marking up the layout of the internals on the HDPE baseplate.

                            IMG_20191015_174806.jpg

                            With a LiPo battery still to add, It's going to be cozy in there!

                            Final action of the day was to mark up the wheel holes and line up the motors for mounting to the base.

                            IMG_20191015_191151.jpg

                            Now all I need to do is get my hands on a jigsaw to cut the wheel holes, then I can start putting the finished robot together! It's all getting very exciting.
                            Last edited by ; 15 October 2019, 20:38.

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                            • #29
                              Looks like good progress so far. I don't think it'll be that cozy though, Azriel is pretty tight in there for the moment with 2x batteries, a block of ESCs and still need to fit in an axe mechanism, all in a 270x270mm space :P Your photo looks pretty spacey but if it does become a problem, think vertically maybe?

                              When do you plan to debut this?

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                              • #30
                                First and foremost: that jacket... is. Ace.

                                Secondly: that’s a lot of progress, making me look lazy, looking good too, I second Lucy’s suggestion of going vertically, something like a mezzanine floor can add tons of space.

                                Third: that rear tyre looks interesting (and similar wear to mine, lots of motorway?)... yours?

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