WiFi or Bluetooth Control

[iamnotabot (adam)]

Hi folks,

Firstly an apology for asking a question on my very first post on your forum, poor form I know!

Secondly may I express close to shear joy finding an actual old skool forum for a hobby and not just a SubReddit or a Facebook group!

Moving onto my question(s), I have searched but haven’t quite got the confirmation of answer I was seeking, so without further ado:

Question(s):
Q1/ Are Bluetooth or 2.4 GHZ WiFi (which is really somewhere between 2.4 and 2.5) allowed for control in UK Ant weight events? i.e. are they close enough to the normative 2.45Ghz in the rules to be allowed?

Q1.1/ If so, is anyone doing so?

Q1.2/ Does the presence of so many much more powerful 2.4ish GHz transmitters cause significant issues for the weedy Bluetooth or WiFi signals in practice?

Question context:
I stumbled onto one of your videos on YouTube a few days ago and learnt of the existence of the Ant weight class!

Excellent thought I; as I was already thinking of building a couple of 3d printed ESP32+phone app controlled bots to battle my nieces and nephews with, for fun but also to sew the seeds of interest in science and engineering… Now slightly introduced to the nomenclature I believe what I was planning is best described as a couple of non-destructive plastic ants.

I have a bit of experience with microcontrollers and hobby electronics so my go to to keep costs down will be to use a small ESP32 devboard and an appropriate H-bridge breakout board and use mine and my wifes smartphones as the controllers with an app (possibly just blynk or remoteXY if I’m feeling lazy). A transmitted rolling alive counter from the phones and an if statement in the esp code should provide a reliable failsafing strategy.

If my low cost control strategy is legal I might well be inclined to follow the rest of the ant weight rules and one day popup at an event. Otherwise if my plastic ants will be constrained to the back garden arena I’ll give myself some freedom and probably package some larger batteries so we can play longer.

:+)

[iamnotabot (adam)]

Ok, scrolled down a few threads and found the answer I couldn’t with the search feature .

Bluetooth it is. Will try and keep the back yard bots Ant class legal incase we come to an event one day.

I do believe this will be my Christmas shutdown home project

[Joe (Joe Brown)]

Hey Adam,

Welcome to the forum! We’re enjoying the old school feel here too!

Bluetooth / Wifi both welcome - just need to ensure the bot failsafes if it loses connection (eg - bot doesn’t move if transmitter turned off)

We’re looking to test out and maybe stock some Robopads in the future which are a wifi based one just as an example

Definitely seen people use game controllers like PS4 over bluetooth before.

[IrregularJoe (Joe Earlam)]

Can’t speak for the rules, but I know you can pair an ESP32 to a bluetooth Playstation or Xbox controller. For the price of a couple of knock off PS4 Dualshocks I’d recommend that over a phone app!

Also a suggestion for casual ant play, if you can design around NiMH 1/2AAA cells they’re much safer than tiny lipos, we use them for Hackspace demo ants because you don’t need to worry about low voltage cutoffs or cell damage.

Finally, if you need any help making it all play well together please shout, I’m an electronics person and I’m already a couple of revisions deep on my custom Beetleweight controller! There’s also a great youtuber who goes by Haase Industries, he’s a teenager building antweight and sumo bot electronics around the ESP32 (including custom TX) and might give you some inspiration.

Love to see more custom electronics in robot combat

[iamnotabot (adam)]

What a capable little board! Assuming it can do pwm output on at least one of it’s gpio pins that’s close to an all in one solution. I’ll do a bit of more detailed research into them later.

Hmmm console controllers… the muscle memory carry over using a game controller would be certainly be advantageous…

[iamnotabot (adam)]

NiMH probably a sensible call I’d already jumped ahead and was planning to include a little 2S BMS board in the mix.

I’ve got 2 Xbox controllers staring my in the face will probs use them! I’d jumped to phone app as it’s my default lazy way of adding user interfaces with esp projects

[MarkR (Mark Robson)]

To answer your questions:

1. Yes, Bluetooth, wifi, or any other digital protocol which uses permitted frequencies is allowed. It must failsafe correctly, stopping if it loses signal.
   1A. Yes, I have done it in competition. I have also seen one or two others which use similar radios.
2. Does interference happen?

Not very much. I used a Bluetooth Playstation 3 controller and it was able to get a decent signal, even in the rumble with loads of other 2.4ghz transmitters turned on.

I would not recommend the PS3 controllers, but I heard that some of the Xbox controllers are better. The PS3 controller will not pair over Bluetooth, it needs usb.

Also bear in mind that most of the video game controllers (at least the ones I tried) are Bluetooth classic, not Bluetooth low-energy. Some chips only support BLE and won’t support them.

The libraries for firmware can also be a headache.

Good luck anyway.

[iamnotabot (adam)]

Thanks Mark, this is all very encouraging news.

ESP32 chipsets I think universally supports classic Bluetooth so I should be all good there. I’ve only once been forced to use Bluetooth LE on a ESP32 based project (for a friend’s iPhone compatibility) I was thoroughly unimpressed by it’s range and reliability v.s. the classic Bluetooth mode from the same dev. board.

With my limited sample of various ESP32 dev. boards used in hobby projects I’ve generally found:

Bluetooth Classic reliable even at ridiculous range well beyond quoted specs.

Bluetooth LE, disappointing in all regards.

2.4ghz WiFi hotspot from ESP32 reliable, though not quite the ridiculous range as Bluetooth Classic.

I’ve never implemented a project in such a noisy signal environment though hence my gentle worries re interference, these worries which are now nicely squashed thank you.

I think BT Classic will once more be my go to!

Really looking forward to this one, I can see I will as ever be fighting my tendancy to massively over complicate a solution . As with most things the possibilities are near endless!

Hopefully I’ll have the time over Christmas to relax in the zen like virtual bubble of FreeCAD & the Arduino IDE and get something printed-assembled-coded and vaguely drivable

[iamnotabot (adam)]

After a read arround the wiki and a chat with the robopad gang (Blaze) I’ve ordered 2 boards to try out in the backyard bots V1. Their new v1.3 boards and the upcoming features in their firmware has everything I was initially thinking of doing myself.

[MarkR (Mark Robson)]

You may want to look at Team Panic’s latest video, there he explains why he didn’t use the PS3 controller and why it doesn’t work with (most) ESP32 chips.

[iamnotabot (adam)]

Will look up team panic on YouTube!

V1 of the back yard bots is just going to use robopad’s boards with stock release firmware and possibly some beta releases when they release state of charge monitoring, along with their phone browser interface.

I’m still keen to do my own ESP32 setup though. I found plenty of prior art on GitHub to build on using Xbox One controllers with ESP32 boards. As I have both a spare undeployed ESP32 devkit board and an Xbox I’m deffo going to have a play at some point.

More than anything I’d like the excuse to learn kicad to design a nice custom all in one board. Previously my hobby electronics projects haven’t really had space or weight requirements so I’ve never strayed beyond strip/ protoboard and through hole components…

[iamnotabot (adam)]

RobotPad initial report: Extremely positive!
From first boot to motor control and servo control, about 10mins, truly impressively easy!

I was gifted an evening to tinker yesterday so I’ve made a start and got my Christmas holiday project a bit ahead of schedule

Forewarning, be kind… I’ve done negatable minutes of CAD in about the last 14years, and just started with FreeCAD about a month ago when I got my first 3d printer. Also it as too blummin cold in the shed to sit out with my soldering station so used a giant automotive wiring soldering iron that’s rather more portable to use at my cramped home office desk but even through hole soldering wires on a PCD with it is like hanging a picture with a sledge hammer…

Anyway, tadarrrr, half a plastic ant weight:

RoboPad v1.3
M20 500rpm drive motors
ALzRC Servo
300Mah Liperior 65C - 130C battery pack - (massively, massively, overkill, but struggled sourcing reasonably priced 200Mah packs from trustworthy sellers)
Printed for now in cheap JAYO PLA

Dimensions (once top half and wheels fitted), 100 x 100 x 33mm
Currently 93g so far

I’m going to do the wheels and the lifter arm next, before mirroring the chassis half (and adding screw head clearance) for the top. Also need to swap in my 0.2mm nozzle as the 1.6mm holes for M2 self tapping screws get lost in the slicing for a 0.4 nozzle.

Blaze (RoboPad) tells me battery charge monitoring is coming in a future firmware so I’m signed up to try it out when a beta release comes. Hence I decided to omit packaging SOC monitoring electronics LED’s etc.

There is also support for gamepads already so will play with that to benchmark drivability vs the phone, though need to make some wheels first

I might print the final chassis(s) in clear PLA so we can see the power / connection status lights without adding holes through the chassis, not sure…

[IrregularJoe (Joe Earlam)]

giant automotive wiring soldering iron that’s rather more portable to use at my cramped home office desk but even through hole soldering wires on a PCD with it is like hanging a picture with a sledge hammer…

Skill issue. (Sorry, any excuse to flex that clip.)

I would recommend against the 0.2mm nozzle, you’ll be waiting hours to iterate on your design, especially if you switch to printing a filament that doesn’t print as fast, like TPU. You should be good with the 0.4mm nozzle, although your slicer might need tweaking. You could also just design in a taper or countersink on the hole so you have somewhere to start a pilot drill.

Bot is looking good though! You’re doing extremely well having only a few weeks experience in FreeCAD, I didn’t enjoy that learning curve.

[iamnotabot (adam)]

Is that you in the YouTube clip?! If so bravo sir! I’ll not blame my tools again!

FreeCAD is an interesting beast isn’t it… I’m a big fan of open source stuff though so am stubbornly sticking to it!

What I thought was a slicing problem was actually entirely a comical user error… I imported the wrong step file into the slicer, one made before adding the screw pilot holes! So I am very happily staying with the .4 nozzle!

I had a bit of time this evening to fiddle so printed the last iteration of the chassis ‘lower’, mirrored it for the ‘upper’ added the screw head counter bores and moved the red power LED hole to show the blinking blue connection LED on the other side of the robopad.

Top:

Bottom:

Current weight 142g, not sure where to spend the 8grams!

The seam around the perimeter disappears with more screws installed, as pictured only 4 of 20 are installed which is probably enough for gentle flipper v.s. flipper home play. Anyway not fitting all 20 anytime soon, probably never, but maybe if I come to one of your events one day and send it in for comic relief in a full combat rumble match help it survive a few seconds longer…

For this evenings driving practice I’ve been driving with the top off and a 2S battery monitor board plugged in to keep an eye on the state of charge. The runtime is ridiculous, 300mAh is definitely way too big of a battery!

I’ve also refined the nodemap on the robopad a bit, got a flipper quick fire button, stick in place lifter slider, inverse controls button for easy both ways up driving. But currently using tank steer, which I thought would be easier than it is! Much respect to anyone who can master that! Think next on the list is to mix motor controls onto a single joystick style control, before moving onto making it work with an Xbox controller. Once working with an Xbox controller the phone display will be all instruments and no controls, that is the idea anyway…

[nevsie (Neil Evans)]

Probably way late to this party! But I have been putting in a bit of work with reference to gaming pads, and the ESP 32.
In short my aim was to go malenki sized.

The issues - most controllers are Bluetooth Classic, that means bigger older, ESP32 chip sets. So tiny S3 or C3 boards were out the window. You can use the old D1 Minis though if you have enough space… But these were still too big for my intentions.

So custom board was my plan. I got this far:

It uses a EP32 PICO chip - so we get BT Classic, and a nice small size.
I matched the Malenki format, input output where possible, and added a bunch of extra pin outputs on the back.

Software wise, I was using Bluepad32 for the controller connection. It basically supports everything, so yes that means you could use a Wii steering wheel, Ps3-Ps5, xbox, even a FireStick remote!!! I successfully got it locking to each transmitters specific MacCode, so no risk of it going wild. And likewise, I got a failsafe setup in place too.

I got the board priced and it was reasonable, but because it gets a bit hot, it was more expensive to make than a malenki - but chip wise, way more powerful!!! Costs are still about half the price of retail malenki.

And that is as far as I got.
The intention was to put higher amp motor drivers, handle higher voltage input current, etc, etc. I also wanted to remove the PCB antenna and put on a ceramic chip on, making it about 4mm smaller again. But this will be future steps.

Anyhow, I am happy to share this, and or work with someone on it, and get a few made… etc etc. but it lost momentum, so i might need a nudge!

[MarkR (Mark Robson)]

It looks good, but that regulator looks massive, I understand that you need more current than (e.g.) on the Malenki.

The esp32 chip looks like it uses a lot of space but it does the job of quite a lot of gubbins off the Malenki (crystal inside, radio inside etc)

[iamnotabot (adam)]

Excellent, if you open source your project I’ll certainly be copying bits!

I think for the next project it’s time to build something more involved and far more dangerous to come play with you guys! I’m keen to make an all-in-1 board of my own, preferably with brushed drive motor and brushless weapon driver all on board.

“Project update”
My starter robopad home bots are fully sorted and thoroughly kitchen battle tested now, Xbox controller controlled, speed sensitive steering etc etc super easy to drive.

Hopefully with some downtime over Christmas I’ll be sharing .step files, Bambu studio .3mf setup, writing up documentation for the ‘control code’ (nodemap), wiring diagram, wire lengths etc etc ready for the masses of people unwrapping 3d printers. Blaze is keen to feature my nodemap as a gamepad controlled example for the robopad wiki once I’ve documented it all up. Expect a forum post in the relevant BBB sub forum…

[nevsie (Neil Evans)]

Hey Mark,
100% the regulator is huge. This was a recommended one from the ESP32 side, I think for heat, and maybe as part of the fact they do USB C for power. Not 100% sure, but still overkill and another part I was looking to adjust.

You will also notice a large amount of familiarity with the Malenki, as that is what you taught me from! But why change a winning formula!

Lots to work on. I’ll get there eventually!

[nevsie (Neil Evans)]

Blazes pads are great, and to be honest, I am not up to date with them. I will need to read up on the latest version a bit more.