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RC Car

Mon Jan 15, 2018 9:23 pm

Hi, i am very new to projects with a raspberry Pi and have decided that i would like to turn one into a remote control car, i have been looking and possible waves i could use for the wireless transmission and i only seem to be able to find WiFi, bluetooth, or infared, and none of these really have the range i was looking for, i would like it to have a range of around 50 metres minimum, im not really sure if this is even close to possible but there is no harm in asking i guess. I am also uneducated in regards to how i should power this thing. i have established that the two motors will demand around 5ish volts, how do i go about solving this issue because i believe that the raspberry pi (very old i know, thats why im turning it into a car :lol: ) can only send 3.3 volts how do i go about changing this, it will obviously need to be powered without being plugged into a wall and am unsure how to setup a battery pack and raspberry pi without blowing it up. Thanks in advance

P.S sorry for my noobiness

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Re: RC Car remote control

Tue Jan 16, 2018 11:12 am

To drive the motors (assuming they are DC motors) you need an H bridge. Plenty of different types around for various voltages and currents. There are also some HATs around that make it really easy to interface to a pi - but check the motor's requirements against the bridge spec.

for example https://www.adafruit.com/product/2348 or https://shop.pimoroni.com/products/explorer-phat.

As for the distance, if wifi isn't congested where you are, then wifi should be OK for 50m line of sight - especially if you don't want to stream video.

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Location: Dorset

Re: RC Car

Thu Feb 01, 2018 4:18 pm

OK, I have done this. I picked up an old RC car at the tip and replaced the RC receiver with a Raspberry Pi. Here it is in action: https://www.youtube.com/watch?v=l8Xdn60 ... e=youtu.be

I won't repeat here all the things that I went through to get it going, But basically it uses a program called WebIOPi which unfortunately is no longer supported. It has been replaced by Cayenne. I'm not sure if you can get that to work. WebIOPi won't work with Stretch.

Because I always use a fixed IP address and WiFi ESSID on my R-Pi work, I got an old Access point and use it out where I want to play with the car.

Here is my writeup about it. You might want to find blogs 2-,3- and 4- on this as I tried different IOT programs.
http://madsmaddad.blogspot.co.uk/2016/0 ... c-car.html

Happy to respond to any questions. I would be interested to hear if anyone else has done similar.
Oh, and if anyone knows of a cheap Li-Po charger!

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Re: RC Car

Thu Feb 01, 2018 8:31 pm

If you want distance google "long range 433MHz transmitter module"

There is plenty around that will work over Kms

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Re: RC Car

Wed Feb 21, 2018 7:18 am

Bluetooth has the range upto 100 meter, you can use some high range bluetooth dongle with raspberry pi as discussed here viewtopic.php?t=97206.
Even RF has much higher range and as far as I know these are the only wireless technologies (Bluetooth, wifi, RF), which are easiar to interface with Raspberry pi. I have built this Raspberry Pi RC car and able to control with 10-15 meter with normal bluetooth phone.

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Re: RC Car

Fri Mar 30, 2018 8:09 pm

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Location: Dorset

Re: RC Car

Sat Mar 31, 2018 8:10 am

psvtg wrote:
Fri Mar 30, 2018 8:09 pm
And this is mine
Tell me more about how you built it? Is it off-the-shelf parts. What is the programming- an app or homegrown?


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Re: RC Car

Sun Apr 01, 2018 8:47 pm

I have done this, using wi-fi, and got a bit frustrated with the steering control, the original had plastic gears and a hair spring centring mechanism. I tried replacing this with a servo which worked better but still was imprecise and slow to react. The donor setup was very tight on space limiting scope to improve. Since then I have built a 'cambot' based on a tracked chasis which has proved much more controllable. After a lot of googling I have been able to set up a web server on the pi and an html/php front end which gives a camera image, pan/tilt control as well as forward/back/left/right buttons. The response times between laptop running the front end and cambot are very short and adequate for my purposes. I recently added a python flask script to gather distances from four ultrasonic sensors determine whether the way forward or back is blocked and send the result to the front end the results are included a 'post' of a hidden forms inputs (from the buttons) allowing the control script to, for example, stop the motors when the way forward is blocked and a forward button pressed. Initial results have been good with a blocked message doing the return journey in plenty of time to stop the cambot.

I have a set of three UnFi access points covering the three floors of our house, one is a more powerful weatherproof unit that has a range well over 50 metres - using a flat ethernet cable and poe I can hang it out of a third floor window which gives me plenty of coverage. I have just put a Pi 3b+ into the cambot because of the better wi-fi on it. However, as my earlier post indicates battery power is currently a problem as the regulators seem to cap current at 1.5 amps..

I expect there will be a solution to this before long. In any event the project has been a great way of getting to grips with python, flask, nginx, php, and Rpi_Cam_Web_Interface, and of course a limited appreciation of raspian.

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Re: RC Car

Mon Apr 01, 2019 4:30 pm

Hi. Again. I have got mine working free of my in-house Wifi by configuring the R-Pi as an Access point. I can give you the link to that if you can't find one. One problem that I found is that not all Wireless dongles will work in AP mode.
https://wiki.archlinux.org/index.php/so ... cess_point

Mine is not as capable as yours but is an AP and a webserver built using Flask, Python and HTML.

I would love to have an eye over your code.

Peter M.

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