Giving an RC tank a fire control computer


[Vincent] plays around with remote control tanks, and even though his current model is a WWII-era armor piece, he’d still like modern accoutrements such as a fire control computer and laser sighting for his main gun. His latest project did just that (French, Google translation) with the help of an Arduino, a few modifications to the receiver, and an IR rangefinder.

The stock RC tank includes servos to move the turret and the requisite electronics to fire an Airsoft gun. The precision of the mechanical movements inside the turret weren’t very precise, though, so [Vincent] had to gear down the servos to turn large movements into slight adjustments. After that, he installed an IR rangefinder and laser diode onto the barrel that allowed the gun to sight a target and read its distance.

After some experimentation with the rangefinder and laser, [Vincent] plotted data from firing a few BBs at a whole bunch of distances and targets. The graph came out fairly linear, and after plugging this into a graphing calculator, he was able to find an equation that took into account the distance and angle so the Arduino-powered fire control computer would hit its mark.

The accuracy of the gun is very impressive, all things considered. [Vincent] is able to accurately fire BBs downrange and hit an 8×12 cm target at five meters. You can check out that action below.

29 thoughts on “Giving an RC tank a fire control computer

    1. great work. And as to an arduino rant…
      Wonder if it might be possible for a skilled model engineer, to makes a miniature analogue mechanical fire control computer, that would be quite in keeping with WW2 era equipment

        1. yes they did require input via people, but only for continuous updating of target data, where shells actually landed, atmospherics and to input predictions of where the target might be going. That’s manly because the data was collected manually anyway I’m pretty sure even now tankers will sight their targets before pressing a trigger to let off a round! Once that round is off, updates are only necessary if you want to fire at that target again. range is almost certainly automated today but I figure there’s still 2 variables that are input by human (elevation and rotation). In this kind of application it would probably be easiest to think of a fire control computer to be more like a servo system, taking aiming information from a human (or a different sub system if the aiming is automated), and then figures out how best to get the round to the right place.

        1. I am surprised! I doubt it would need to be that complicated a gunnery computer. Distances could have been found using Coincidence rangefinders, simple enough to have that output on a dial( as a backup) and also as a shaft rotation. Then use the shaft output from the rangefinder to turn a cam. Depending on the shape of the cam, height of cam=elevation angle.
          If the range finder and gun are referenced to the tank hull there isn’t even any need to correct for the tank body going up/down/across slopes. With a power traverse(as many tanks had) it wouldn’t be difficult to rig up a servo system to keep the gun pointing in the direction needed to hit where the rangefinder is aimed/focused.

  1. That’s so damn cool. My favorite part is the graphing calculator. I carried a TI-83 for ages and it got used for games more than anything else, but it’s absolutely amazing what that little thing is capable of.

  2. hello everyone…
    i am new to this group.came across this project.a very honest and dedicated work indeed. i would like to dwell upon another way of using a ultracapacitor for RC heptrs or movable vehicles.since it can gets charged even wid a small battery and using LM317 IC this capacitor can greatly reduce the heavier bty load.At the same time if it is incorporated well,it can help in flying the RC heptr for hours non stop using smaller solar chips like plates as wings and body nd can slowly keep charging a set of two capacitors wid a transistor / 555 timer circuit whose task is to imdtly switch over to another bank when the first one gets discharged.

    i need somebody to help me in learning arduino board or rasberry pi……anybody pls help me….

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