Rainer Ilgen

The Frog is a Arduino powered RC-Car project of mine.

I bought an cheep RC-Car @ Zellers and removed the Toy-Brain and replaced it with an DFRobot Arduino FIO.

Following Control option are in my mind:

1. XBee and PC program
2. XBee and XBee-Web Server-Relay
3. BluetoothBee and Android phone
4. Autonomous mode

I will see if I get everything realized.

1. Hardware – Frog
   1. RC-Car
   2. DFRobot Arduino FIO
   3. Digi Xbee Series 2 or SeeedStudio BluetoothBee
   4. Sparkfun Serial Motor Controler
   5. SeeedStudio Ultrasonic Sensor
   6. Pololu S8V3A Step-Up / Step-Down Voltage Regulator
   7. SeeedStudio 3.7V 1Ah LiPo
   8. blue, red and green LEDs
   9. Cables
2. Hardware – PC
   1. SeeedStudio UartSbee
   2. Digi Xbee Series 2

Put some light into the Frog

I started with the easiest part. Lets drill some holes and put LEDs for Headlights, Break and Signals in.

Lets Test the Frog

One of the first tests with external power supply, SeeedStudio Seeeduino 328, Grove Shield, SeeedStudio Bees Shield, SeeedStudio RFBee and a simple serial control sketch.

Controlling the Frog only over Serial is boring

Ok then lets add a Ultrasonic Ping sensor and update the sketch.

After couple hours later it was done and the Frog was alive. Still not perfect but alive.

[Pics here]

Next Steps:

1. Add the Sparkfun Serial Motor Driver (I had to wait for the order)
2. Add the DFRobot Arduino FIO (I had to wait again for the order)
3. Finalize the wiring and put everything together
4. Finish the sketch.

Rewire the Gearbox

Next Step was to remove the cheep wires from the Gearbox. I took the Gearbox apart and rewired the motors. I put the Gearbox back together and tested everything.

The Serial Motor Driver and the FIO arrived

Finally the missing parts arrived and I could finish the wiring. After putting everything into the frog and uploading the sketch I recognized that the Motor Driver was talking to fast to the Arduino – 115200bps. So I checked on Sparkfun if there is an other firmware I could use with the Motor Drive. No wasn’t. OK then modify the firmware. Lucky me the Motor Drive has an ATmega328. Problem I never programmed an ATmega328 directly before – I’m just new in this area. OK I knew how to use the Arduino with ArduinoISP and had still an Breadboard wired out of my BlinkM project. I knew enough about avrdude and if you run into problems signature problems check out grellis blog. It helped me a while ago – THX grelli. After a couple hours Google and I knew what I had to do. Little bit later the Motor Driver was talking to the FIO in 19200bps.

Next small Problem I run into was that the Current Threshold of the Motor Driver was to low and once a while the Motor Driver stopped. OK back to modify the firmware and burn it onto the ATmega328. Cool now it is working good.

Now it only suckz that I can control one motor at the same time. I had to send two serial commands each time. And again modification time for the firmware. After this was done I could control both motors with one command. Then the next problem.

Every second serial command the Motor Driver was telling me “Incorrect Command Length” – Damn it. OK then change also this routine too.

Then finally the Motor Driver was working like I want it, everything back into the Frog. But … guess … yes another problem. The Power StepUp I want to use was limited to 100mA peak. But the motors were pulling at least 120mh peak, so only one motor would work.

Now I’m waiting for a Pololu S8V3A Step-Up / Step-Down Voltage Regulator.

• Typical continuous output current: 300 mA
• Input voltage: 1.5V to 12V
• Output voltage: : 2V to 12V

I hope that no new problems are showing up and I can run the Frog with my 3.7V LiPo. I still need to program an Android App to control the Frog over Bluetooth with my cellphone. And I’m still not happy with autonoumes mode … the Frog still has to learn, but without testing on a running Frog … no chance.

MotorDriver