Introduction: Easy, Affordable Way (guide) to Homemade RC Car.
/* THIS IS MY FIRST INSTRUCTABLE. SO BE GENTLE WITH ME. I AM BIG FAN OF INSTRUCTABLE FROM A LONG TIME, IT HELPED ME LOT. NOW POSTING MY OWN SO IT MAY HELP OTHER READERS LIKE ME. PLEASE GIVE ME SUGGESTIONS .I WANT KNOWLEDGE FROM EVERYONE TO IMPROVE MY WORK.*/
In this instructable I’m going to show you all how to convert old cheap china RC car to a powerful Bluetooth controlled RC car. Since this is home made fun project, I will keep this project as simple, cheap as possible. They are many other instructables for RC car but this is my way of making and representing. I am going to use Arduino for this project. So let’s get started.
BENEFITS OVER TRADITIONAL RC.
1. This has range of 15 to 20 mts.
2. Has bright lights.
3. More power and speed.
4. Can be controlled by any android phone. No need to handle a specific frequency remote controller.
5. Has horn
6. Speed control.
7. Battery level indicator.
“ABOUT SOFTWARE AND ARDUINO CODE.”
This car uses an android app and Arduino code which is developed by ARDUinoautoMOTIVE for their site click here.
Thanks to the author ‘Vasilakis Michalis’ , for his work.
Step 1: BILL OF PARTS
recommend eBay.in/ site for buying parts which u don’t have. Because there u find them cheap.
· Any type of electronic RC car. (Had one, so it’s free.)
· Arduino Uno board (₹300-500 for a clone)
· 1x L293D H-bridge IC (₹65)
· HC 06 or HC 05 Bluetooth module (₹300) [if u have HC 05, I’ll show u how to configure]
· 2x bright white led and 2x red led. (Salvaged so free for me otherwise cost 2₹ for each approx.)
· Male header pins.
· 1x speaker/ buzzer for horn. (₹5)
· Resistors 1M Ω and 100k Ω for battery level (₹1 each)
· Veroboard (₹20-50)
** The price of components is mentioned in Indian rupees. 1 US dollar $ =67.035 Indian rupees ₹.
Tools and others supplies.
Soldering iron, soldering wire, insulation tape, wires, super glue (fevi kwik), glue gun, etc.
NOTE: Arduino board, Bluetooth module and probably the h-bridge IC, accept these things u can salvage other parts from old electronics. No need to buy them. Buy an Arduino Uno clone if u don’t have one do not buy original made in Italy because it may cost u ₹1500.its up to you which one to buy. Clone works same as original. U CAN USE EBAY.IN FIRST TIME BUYER COUPON CODE FOR ₹ 100 OFF ON MINIMUM PURCHASE OF ₹ 300.
Step 3: ARUDINO AND CODE
Arduino is an open source electronics platform.
Their board can be used for fun projects and lots more. If u are new to Arduino platform and had never used it before, then learn about it by googling or read other instructables on how to use Arduino and program it. It’s fun! Visit there official Arduino site here.
Upload the attached code to Arduino. Now your Arduino board is ready to be used with RC car.
Step 4: MOTOR DRIVER SHIELD /CONTROLLER BOARD.
So what is motor driver and why we are using it
Before that u need to understand what is h-Bridge. In an RC car they are two motors. One for driving the car forward and backward and another for direction left or right. To achieve this we need to rotate motor clockwise or anticlockwise accordingly. This is done by using h-Bridge. The h bridge is designed to drive motor clockwise and anticlockwise. To reverse a motor, the supply must be reversed and this is what the h-bridge does. Read more here. H-bridge can be made with switches, transistors, relays. We are going to use h-bridge IC. You can use transistors for this, but it takes more space. L293D IC occupy less space. And easy to mount. Arduino output pin can supply only 50 mA of current. But we need more current to drive motors. Which is done by this motor driver IC.
You can design PCB and solder everything together. But I have used Veroboard.
I have attached L293D IC datasheet refer it for details.
Step 5: LIGHTS AND HORN BUZZER.
You can connect horn buzzer directly to out pin.
But to light the LED’s to their maximum brightness u need a transistor, which will operate in switching mode and amplify the Arduino output pin current to lit LED's at their full brightness. Output pin current of arduino uno is 20mA.Read more about transistors here. I have used a BC547 transistor u can use any general purpose transistor like 2N2222 or 2N3904. U can connect 100Ω resistor in series with led if u wish. But I didn't add as my LED's were giving full brightness without resistor if i add then it may reduce brightness. But it is advisable to add one . But I used a 220 Ω resistor in series with back red LED's to limit current drawn by them, so front LED's light at their full brightness. I decided to use led strips which are mostly used in automobile lightning. because they fit nicely and looks good. see photos.
Step 6: BLUETOOTH MODULE AND CONNECTIONS.
BLUETOOTH MODULE AND CONNECTIONS.
They are basically two Bluetooth modules available for the purpose. HC-05 module which can act as both master and slave which u can configure using AT commands or u can use HC-06 module which act only as slave only. U can connect HC-06 directly and start using it no configuration required. You can use any one of them. But if u don’t have one and u want to buy one then I will recommend HC-05 because it is much cheaper and can be configured according your need (i.e. master or slave). Here we r going to use module in “SLAVE” mode.
Android phone will give command it will receive and will send it to Arduino. If you don’t know how to set the HC-05 module then refer this instructable very illustrative.
NOTE: THERE IS 'EN' PIN ON THE HC-05 MODULE,WHERE KEY PIN SHOULD BE THERE.THE KEY PIN IS USED TO SET HC-05 TO SLAVE OR MASTER MODE. U CAN SOLDER A SMALL WIRE TO '34 PIN' ON MODULE AND USE IT AS KEY PIN.
Step 7: BATTERY FOR POWER SUPPLY.
All china RC car have a battery compartment where u
can insert 4x AA 1.5volts cells. These can be rechargeable or dry cells. Anyone can use four NiMH cells to power your RC, which is in did easy and straight forward. But this may cost you. Since this car is going to be custom made I think we should use the things lying around useless.
That’s y I decided to make a battery pack from an old laptop battery. [This is optional. If u don’t have old laptop battery and have NiMH cells u may straight away skip this step. ;) ]
To make a battery pack from laptop battery,
· Break opened it and get all those Li-ion 18650 cells. In my case they were six. Each cell of 3.7volts and 2200mAh.
· We are going to make a pack of 12volts. So connect three cells in series. REFER DIAGRAM AND PHOTOS TO ASSEMBLE THE PACK.
· These cells when fully charged reach a voltage of 4.2 volts per cell.
· These cells are more capable of powering RC car like this.
Some advantages of Li-ion 18650 over NiMH.
1. High energy density-potential for yet higher capacities.
2. Does not need prolonged priming when new. One regular charge is all that’s needed.
3. Relatively low self-discharge, less than half that of nickel-based batteries.
4. Low Maintenance-no periodic discharge is needed; there is no memory.
5. Cells can provide very high current to applications such as power tools.
Because of all these reasons, I think it is always better to salvage those 18650 cells to flourish your project rather than throwing them to contaminate environment.
I used a 9 volt connector from old dead battery, for battery pack connection. Other four wires coming out of pack are for JST XH connector technically used for balancing the cells.
Step 8: MAKING a CUSTOM CHARGER FOR BATTERY PACK. [OPTIONAL]
Once you assembled your custom battery pack, you
have to charge it when it gets empty. i said this is optional because u may use NiMH cells and can use nickel metal-hydride battery charger or if u made above pack you can use a special balance Li-ion or Li-PO balanced charger.
These Li-ion cells are very special and they should be charged with a proper balance of current and voltage.
For that reason I decided to make a charger. THIS CHARGER CIRCUIT IS DESIGNED BY SCOTT HENION. THANK HIM FOR HIS WORK. For more details visit his site shdesigns.
Make the circuit as shown in photos and diagram.i have attached a file with diagram.
Step 9: PUTTING ALL TOGETHER AND MAKING RC READY.
Once everything, motor driver shield, Arduino,
battery pack, LEDs ready, put everything in its place. Fix properly. According to car body u have to arrange so it doesn’t reduce beauty of car. U can see how I arranged in photos.
I fixed the pcb with super glue below the car body.
Also i used female header pin connecting cable for motor connection so it become easy to remove.
i have used a buck converter (voltage regulator) to step down the voltage from battery to 7.4 volts, which i gave input to Vin pin of arduino uno so that it doesn't get too hot. i used it so my uno remains safe :)
Once all this is done, put on the switch and your RC is ready for a race with more power and awesome look.
Install the attached 'apk' file of android app that you can use to control your car. Also if u want u can use any other app from play store of your choice.
soon ill be comming with version 2 of this car. so stay tuned :)
Thanks for reading and paying attention to me.
If u liked my work then please vote me for contest.
Thanks again. Jai hind!
Step 10: Video.
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Please be positive and constructive.