Mini Motor Driver with nrf24l01 socket.

I made a little motor driver /servo controller with a nrf24l01 socket for small dc motors.
Can handle a 1.5 - 2 amps.
It about the size of an arduino pro mini and meant for little coreless motors for boats cars mini helicopters and indoor planes or whatever you want.

If you have a nrf24l01 it is a complete rc unit.
Otherwise the socket is used to burn the bootloader and then can be used for other things.

I made mine with an atmega8 but any 88/168/328 will work. (I don’t recommend using the atmega8 as it does not have hardware pwm on the pins connected to the driver).

Note: the Atmega is running at 8Mhz as the voltage regulator is a 3.3 volt. This is so the nrf24 module can be powered from the same source.
If you don’t use a Nrf24 radio then you can use a 5 volt regulator and run at 16mhz. You can also use the internal oscilator and put a pin header in where the xtal would be.
(thats why its a big through hole part)

Will work between 3.5 and 9 volts depending on parts and setup. The servo is powered right from the raw input voltage so should not exceed 6 volts if you want to power the servo through the board.

I will post the gerber files here in case anyone wants to give it a go, I make up stuff like this to fill up board space when I order pcbs and have room left over.

Here’s the drawbacks…
This is a circuit designed to be as small as possible… there is no reverse circuit protection. I use polarized rc plugs on all my things… There is also nothing to stop you from turning on both sides
of the bridge in your sketch and blowing the bridge I haven’t done it yet but you must keep this in mind.

My schematics are terrible. I use diptrace and it makes ugly schematics and mine are the worst. If anyone wants to make a more legible schematic that would be awesome!
I’ll put up the diptrace schematic too.

So if there is interest I will keep posting what i can.
I didn’t know where to post it, Its not good enough to be a finished project but it works well for small motors, haven’t tested it to breaking point yet.
I am having fun with it so i figured I would share.

Here are a couple videos of it in action.

It can be made for about $2 with ebay bits! Canadian!

Parts List
Atmega8 /88/168/328
sot-223 voltage regualtor LDO
2 each AO3402/3401 mosfets and 2 MMBT2222A transistors
bunch of small 805 resistors ( see picture… you don’t have to be exact).
2 10 uf caps
1 0.1 uf caps
smd 0805 LED
1 220 uf cap.

I’ll put up my simple sketch that I use to control it when I get it cleaned up. Otherwise just remember DO NOT TURN PINS 5 and 6 HIGH AT THE SAME TIME.

I’ll try and keep this updated… any suggestions and improvements are greatly appreciated.
Cheers
IMG_20160218_191138.jpg


Alka

schematicDiptrace.zip (17 KB)

sot23allinone.zip (9.2 KB)

Nice videos

Can you make a pdf-file from your schematic? Now the diptrace is needed and I don't want install it now. I have another.

What libraries you use with the NRF24L? I would like use that chip but there are too many libraries.

I am using TMrh20 library for the nrf24l01.

I am not at home now but I will try make a pdf later , the problem is my schematic is hard to read. Opening it with diptrace ( its free for under 300 pins) allows you to follow the connections a little more easily. Also I am terrible at laying out schematics that look nice.

I did a second version of this board that is for controlling 4 motors (single direction), with the nrf24l01 socket and a socket for a 6050 gyro/accelerometer. its a little smaller than this one and can be used in theory for a small quad ( although I never wrote code for this). I'll try and get that up here too ( I would love to see someone smarter than I use it for a little quadcopter).