Fitting the Electronics to the OpenRC F1 Car Build

by Jason King on February 6, 2016

OpenRC F1 ElectronicsAt the end of my Last Blog Post about this OpenRC F1 car build, I mentioned that I was about to pick up some of the electronics for the car.

I’d sourced them from two UK distributors and the first parcel was waiting for me at the Post Office. Well, it turns out that the second parcel full of electronics arrived direct to my house later the same day, so this was it, time for some horsepower!

As well as ordering the brushless motor, electronic speed controller, steering servo, LiPo battery and radio gear, I’d also ordered some gold plated connectors and heat sink.

My good old soldering iron was also sat next to me after finding it in the garage a few days ago, cleaning it up and doing few practice runs, so what better way to start? Time for some soldering…

Soldering Wires and Connectors

After all that build up, my soldering has never been world class. I guess that’s one of the problems with my ‘just get on with it’ approach to doing things. A little time learning how to solder correctly is time well spent, but I didn’t, as I’ve been soldering for years and thought I knew best.

You can see from the pictures where I soldered the various plugs so there’s no need for a detailed explanation of this. However, something you need to get right is this.

If you use these gold plated connectors (which are great by the way and we were using these 25 years ago too), then make sure you never use two male plugs at a power source, as they’re exposed and can easily short out your equipment.

What I mean by this (and refer to the pictures to help) is that the two power sources are the battery (to the speed controller) and the speed controller (to the motor). Short out either of these and you’ll at best damage your equipment beyond repair and at worse cause a chemical fire in the LiPo, which you really don’t want!

Gold Connectors Heat SinkAlso, use heat shrink around all of your plugs as in my pictures, leaving no exposed metal on the female connectors and when you plug them together with the male connectors no metal should be exposed at all.

If you don’t use heat shrink all of every plug will be exposed and will eventually short out whichever way you solder them on.

From the pictures you’ll see that the motor has orange, yellow and blue wires with male connectors and the speed controller equivalent wires have female connectors.

The speed controller red and black wired use male connectors, which can plug directly into the battery female connectors, or you can use the supplied battery cable and solder female connectors onto those.

I hope I got that the right way round, as I sometimes get male and female mixed up, but promise me you won’t quote me out of context on that 🙂 Anyway, that’s enough of the male/female thing or this blog post might start attracting the wrong kind of search traffic.

Initial Electronics Test

So, with all of the wires and plugs in place it was just a matter of plugging it all together (outside of the F1 car) and doing a quick check to make sure it all functions correctly.

Another quick note about Safety. To state the obvious, make sure you always connect the battery to the speed controller the right way around.

F1 ESC and ReceiverI guess you could use alternate male/female connectors on the positive and negatives to ensure this happens, but as my battery has female plugs built in for both, I’m already vulnerable to getting it wrong whatever I do.

I should probably think of a better way of protecting against using the wrong polarity (Tamyia connectors maybe), but for now I just need to be careful.

After connecting it all up I realised that I needed four AA batteries for the transmitter. A quick trip to the shop to buy these (and some chocolate) solved this minor hickup.

I always turn on the transmitter first, in case of interference. Next I switched on the speed controller and hey presto, it all seemed to work fine.

What was initially confusing is that the servo and speed controller plugs fit into the receiver either way around, both the correct way and the wrong way. A little research convinced me that if you get either of these the wrong way around it won’t cause any damage to the electronics.

For reference though, if you use similar equipment to me, the following may help:

  • Brown end wire = common (negative)
  • Red centre wire = positive
  • Yellow end wire = signal

With the positive being in the middle, it’s always correct so that’s partly why it won’t cause any damage by plugging in the plugs the wrong way around. If you have a red wire at either end, you might want to do a little more research and may have to rewire your plugs.

There’s a little procedure you can follow with the speed controller to calibrate the throttle neutral, full, brake and reverse but refer to your instructions for this. For my speed controller the English translation wasn’t fantastic but I still managed to complete the calibration in a minute or so.

All in all the electronics worked well together and as you should always store LiPo batteries with charge in them, I didn’t need to charge the battery before doing these tests as it was already charged. The receiver was pre matched to the transmitter too which meant that step wasn’t necessary either.

Fitting the Steering Servo

The steering servo fitted well in the car, as I’d already checked the measurements before purchasing it. It has metal gears which look quite durable too.

OpenRC F1 ServoI didn’t have a proper servo connector rod, so I used some copper wire for now. It’s strong enough to function correctly but will bend in the event of a crash, further protecting the servo.

For now it seems to work but I needed to make the servo arm hole a little bigger to cater for it.

The servo arm and rod is a little close to the bodywork when it’s fitted to the car, so I may redesign the servo holder to move the servo a little, but I think we might be ok. This is something that needs testing really so I’ll deal with that later.

The servo did need reversing using the little button on the transmitter. Make sure you check this before you do your first road test, but I’m sure you’d quickly notice if you turn left using the controller but the car goes right.

Also, I’d test the steering servo before you fit it to the car. This may sound obvious but if you plug it into the receiver the wrong way around it can behave erratically (as neutral and signal will be swapped). The server can usually cope with this but when fitted to your car the servo arm could spin round too far and hit the chassis causing some damage to the servo or car.

The reason I know this is because I did initially plug it in the wrong way (too impatient to check out the wiring) and it did spin erratically. Luckily it wasn’t fitted to the car at the time.

Fitting the Brushless Motor

Something I noticed about the brushless motor when I first tested it was how smooth and quiet it was. For a start (being used to old brushed motors) I though it wasn’t running at full power, but it is and it is very powerful. It’s just really smooth, quite misleadingly so.

Open RC F1 MotorThe pinion gear doesn’t fit though the motor mount hole so fit the motor first, then the pinion gear afterwards.

The pinion gear fits quite tightly, but just make sure that the flat side of the motor shaft aligns with the flat side of the pinion gear hole before fitting it.

I have been wondering whether a standard metal pinion gear would fit. It looks a bit like the 32 pitch standard, but it is a long time since I saw one of these so I’ll check and maybe buy one. It’d just be easier to remove for when the motor needs to be removed from the car.

The pinion and spur gears meshed well, but if it sounds noisy I found adjusting the motor so the gear mesh is closer together helps. Not so close it’s tight, but to reduce the slack which causes the noise.

In the old days of brushless motors the motor had to be run in before ever giving it full throttle. My research tells me that brushless motors have no parts which need to be run in, no brushes for a start.

Feel free to run it in a little before giving it full throttle if you want to be on the safe side, but there’s actually no need with a brushless motor. If you use a brushed motor then yes, you’ll definitely need to run it in well before giving it full throttle.

Future OpenRC F1 Car Plans

I think that pretty much sums up my experience of fitting the electronics, largely painless and successful I think. You’ll notice I haven’t mentioned where to put the battery, receiver and speed controller in the car and how to secure them.

OpenRC F1 LiPoThis is simply because I’ll be taking it for a test run first before I establish the best way to position everything.

One thing I would emphasise though is to ensure the speed controller switch is easily accessible during any testing or general use as it’s your main safety switch if anything goes wrong.

The components do all fit into the car (that’s a good start) but it will be a little tight with all the wiring too. The battery should be mid mounted for balance, as per the picture, with the other electronics fitting around it somehow. I’ll report back on how things are best positioned.

Next time, I’ll hopefully be reporting back on the first test run, which will be both exciting and nerve racking.

Should you wish to follow my progress with this Formula 1 car build then check out my OpenRC F1 Web Page where I publish all updates. To become more involved then feel free to join my new Facebook Group which enables you to comment, ask questions, suggest ideas and generally join in the fun.

Please help spread the word about this project by Liking and Sharing this article with your friends.

Thanks for taking the time to read this.

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