TechTank C/w Coilgun




Introduction: TechTank C/w Coilgun

First images of what has been a work-in-progress for 6 months. The construction is almost complete and 2015 is the year to focus on the programming and electronics side.

Coil-Gun... This is what has inspired the tank as when the coilgun was first tested I was so surprised at the power I thought I would have to incorporate this onto some tracks. It fires a 20mmx6mm steel slug. Have had a number of test fires, it charges to about 340VDC in about 10 seconds and then use an opto to trigger an SCR. Now its all encased I feel its a lot more reliable and less dangerous than having the HV circuit board lying around the table. It has a 1500uf photoflash capacitor.

Tracks and motor have been purchased from hongkong and the body has just evolved over time.

The turret has 2 servos, gyro, ultrasonic and 2 IR distance sesnors and the camera.

The motor controller has an arduino nano plugged into the top and provides PWM, direction and amps for the two drives. The motors have a hall effect speed sensors circuit as well, which Im not sure where to integrate this function, arduino or raspberrypi.

The rear of the unit has a raspberrypi and 3.2" toushscreen + an IR distance sensor.

Power: 2 off 11.3V 3300ma batteries in the undercarriage.

Sound is yet to be completed however have a small amp and a 40mm speaker which will be printed into a holder to look like a satelite dish.

Now whats bought me here is I need help planning the software side which I would like some input from those who have done it before....

Aim of the project

Search autonomously, find a target, aim and shoot. the target could simply be a coloured block in the first instance. Would also want to control everything via smartphone and some functons from the touchscreen

Thoughts soo far :

Raspberrypi running the expanded Firmata.

OpenCV for object detection

All code running in python

Gyro, which I plan on using to keep the barrel straight when the tank is traveling up/down would direct connect to raspberrypi with servo control through firmata.

Smartphone app could use touchOSC, however I would really like to see a streamed image from the camera with range bearings superimposed over the image, so maybe a custom html page served direct from the RPi.

My biggest dilemma at the moment is I would really like to use a Speed PID for each of the motors as I have a speed pulse, however understand firmata does not support this so really torn. I truly believe the 2 motor PID function should belong in the arduino and not the RPi. As the tank is about 200gm heavier on one side I really think I need some low level speed matching so it will track straight.

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    7 years ago on Introduction

    Whoa, this looks cool. Any more info on how you made this (photos of the process, for example?) It would be interesting to see more on how this came together!