Intro: Epic Fail Shovel
It is one of my hobby to hack my kids' toys. They are getting bored easily and so I am. It was end of May last year when I picked this shovel and intended to control it with a smartphone. And the story began ...
Step 1: Dagu Mini Driver
I found this on the market which sounded promising. All-in-one Arduino compatible microcontroller for robot supporting 2 DC motors and 8 micro servos. It is said that there is an english manual but searching through the web I got little information about this driver. Yes I found pinouts and some stories from some guys using this driver for their project, but little detail about how to connect and how to code. Then I had to figure it out myself by testing on it.
Step 2: Wiring
I cut half two female-female jumper wires and soldered it to two DC motors to run the wheels. Then connected them to the Dagu Mini Driver along with three micro servos which were intended to move the shovel's arm. There are pins to plug JYMCU-Bluetooth module directly on board. I an Arduino Uno R3 as an ISP programmer to program this Dagu Mini Driver and it was uploaded successfully.
Step 3: Then I Cry... I Cry... I Cry...
Singing the song "Crybaby" by Mariah Carey was just my runaway from the sadness. At first it was not working. After that I tried to directly connect the MCU through UART to my USB port for programming (without Arduino as ISP). For not knowing what had happened, it just smoked on the MOSFET transistors side.
Then I tried my second board, the same thing happened, on the same transistor side.
I desoldered the good transistor from one board to replace the burnt one on the other board and tried to plug it the third time and guess what?? The same thing happened (-.-")
I gave up. Both my boards were badly burnt at the MOSFETs side. Three times... those were BAD.
I just knew about Arduino for the first time about a few months before I started this Shovel Project. That was my first robotic project. Luckily it didn't kill my heart for knowing more about microcontroller. Until today, writing this epic fail instructables, I just thinking that my first run didn't burn the board, because I powered it with 7.4V 1A battery. When I plugged it in my USB port, it needed more power, so the MOSFETs were working hard to double the power until they got burnt. What a three times lucky it didn't burn my USB port fiuh... I just bring the negative thought into positive :D
But just my thought anyway. If someone have better explanation please kindly share it with us in the comment section ^_^
Step 4: Happy Ending
When I got my new motor driver, I tried to re-connect the motors and servos to the new board. Using Arduino UNO R3 as the processor I did run the bare wheels. I've lost the photos of the wheels. I had drilled the wheel base and plugged the motors in. Then guess what? When I put the rubber treads on, it just didn't move. The standard 3V DC motors couldn't move the stiff rubber treads. It moved when the treads were removed, but what's the fun a shovel without treads?
Giving up with the shovel, I turned it into a tank just by replacing the arm with a pipe. My kids loved their new toys [er.. the tank went back in the box of leftover two months later ha..ha..]. The hack itself was successful. Everyone's happy ^_^
This fail then leads to my successful Android Controlled Arduino Bluetooth Panzer.