- FLS aka Face Like a Shovel
- FLS vs Slash at Robowars Nationals 2012 Ipswich∞
FLS is a 150g antweight that was thrown together for a 2011 event. Since then it's had parts swapped out, tweaked and fine tuned and has gone from a rookie to winning several events including the 2012 nationals. The idea for FLS was to create a super reliable and fast wedge which could fend off the big spinners and push people into the arena's pit.
Here's the pile of parts (POP) that went into FLS along with costs (no shipping).
1: Two cell (2S) 180mah Lithium Polymer Battery Pack∞
2: 3 Channel Hobbyking Receiver∞
- $5 / Comes with Radio
3: BotBitz GM12 50:1 LV Gearmotors x 2 (30:1's shown in photo)∞
4: Lite Flite Wheels 2" Dia x 2∞
5: BotBitz 10AMP ESC x 2∞
6: 5mm thick strip of UHMW Plastic - Free!
7: Paint Scraper Blade - $1
8: Servo Mounting Screws∞
Not shown: GTX3 Radio Transmitter∞
Not shown: Botbitz ANTswitch∞
Total Cost (sans shipping): $98
FLS runs two 50:1 botbitz LV gearmotors. These have proven extremely powerful and provide the large 50mm diameter wheels with lots of pushing power and huge speed. It's important to note that all botbitz LV motors shouldn't be run on more than 2S lipo (7.4v) or they will burn up.
The drive motors in FLS are secured to the robot using a small piece of 0.5mm thick carbon fibre. The motors attach using their faceplate and two 1.6mm screws. This plate is screwed to the robots plastic sides using servo mounting screws.
The wheels on FLS use hubs from much cheaper, lower grip foam wheels from hobbyking with the lite flite wheels. These hubs have been carefully drilled with a 3mm drill bit and pressed onto the gearmotor shafts. With a tiny dab of superglue these have never come off in battle however removing them is quite a challenge!
FLS uses drive power and its bent paint scraper blade to control other robots and deflect spinning weapons. Scraper blades make perfect armour; they are extremely tough and hard to bend. To drill them, a centerdrill is recommended using a drill press on low speed. Bending scraper blades is tricky, as they will crack if bent cold. FLS' blade was bent to shape using a vice and a blowtorch to help soften the bend area.
Originally FLS had hacked servos for drive motors, which was terrible and it barely moved. Using the botbitz 10A escs it is very controllable and reliable. The pistol style radio is a personal preference, some may prefer a stick radio such as the popular T6A∞
To reduce the weight of the robot, the receiver was removed from its casing and wrapped in kapton tape. It's very important you make sure nothing can short out on the electronics! Sharp edges can break through kapton tape so be very careful. This is a sure way to release magic smoke from your robot and for it to stop working.
FLS also uses a botbitz ANTswitch∞
which allows easy, fast and reliable switching of power when it's time to go into the arena.
ADVANCED: The pistol radio used with FLS has been modified using custom firmware to allow tank mixing and advanced settings, competent electronics knowledge is required. The hacking guide can be found here: OverkillRC GT3B Firmware Hacking Guide∞
Any small two cell lipo pack will do. FLS uses less than 100mah of charge per 3minute fight.
If you're just starting out, a great low cost charger is the TG-3∞
balance charger, which can plug directly into the wall socket. Make sure you buy a battery pack with a balance lead if you intend to use this charger.
The main chassis of FLS is constructed from UHMW plastic. This plastic doesn't crack and is extremely tough but a little tricky to find. If you're located in Australia, your local CBC∞
store may have small offcuts at their counter and this is where I source my plastic for next to nothing (but be prepared to be ripped off if you intend to buy it from stock). HDPE plastic is also great for robots and sometimes easier to find. A substitute material is chopping board but make sure the plastic is PE and not PP, with the latter being very fragile and prone to cracking. 0.5mm thick aluminium sheet is used to cover the top and back, with servo mounting screws securing the whole machine together.
And the clear thing out the back? That's polycarbonate coreflute plastic often used for greenhouse and porch roofing. It's proven superior in its ability to keep spinning weapons away from the robot's frame and wheels and weighs almost nothing.