Newbie Project - Radio controlled pop up targets


#1

I am a Windows based IT professional who is learning about Rapsberry Pi etc due to being involved in Linux based IoT projects at work.

I’ve bought myself a Raspberry Pi and have learnt the basics in the Raspberry Pi cookbook; however I learn better when I have a project to immerse myself in.

Rather than work on projects that don’t really have any use to me (other than technical exercises), I would like to build myself a set of pop up targets, which either pop in a sequence or individually and can also be knocked down after a set period of time if they have been missed. Kind of lack a “whack-a-mole” type thing

I’m pretty sure I can code what is needed and my cousin is an architectural blacksmith, so I am confident we can sort the engineering of the target mechanisms. I thought servo motors would be a good way of pushing up and knocking down the targets.

However, rather than being surrounded by wires, that get tangled or tripped over, I would like the targets to be wirelessly controlled, so that they can be individually moved around and repositioned.

Therefore (thanks for persevering), what would be the best hardware solution? I’ve seen the Adafruit 16-Channel PWM / Servo HAT which can control enough servos - however how would the radio transmitter/receiver work with this? Would Arduino be a better route?

I just thought it was worth getting some advice before I spend a load of time and money going down a dead end.

Any and all advice welcome :)


#2

Welcome! It’s cool you’re getting involved in linux-based IoT projects, and the Pi, plus the excellent learning-focussed community behind it ( tee hee! ), is a really great place to start.

I’ve not done much with wireless, but I’ll chime in with some pointers in what’s, hopefully, the right direction.

In this particular project I suspect you’d be best served by something Arduino-like. The cheapest wireless-capable device we stock that might serve your purposes is the Bluno Beetle: http://shop.pimoroni.com/products/bluno-beetle

It uses Bluetooth with a claimed 50m line-of-sight range and I suspect it would be possible to pair a multiple of these to the Pi using a compatible bluetooth adaptor with a good antenna ( not one of those ultra super mega tiny ones ).

It’s really thin on the ground when it comes to tutorials, though, with them tending to be as confusing and vague as this: http://www.dfrobot.com/index.php?route=DFblog/blog&id=283

I think @RogueM has one, though, so he might be able to shed some light.

For a power supply, you could use a regular 5V USB battery, the ones you might charge a mobile phone with on the go. This should plug straight into the Bluno Beetle, then you’ll get 5V from the 5V or VIN pin to power your actuator.

For an actuator, I’m not sure if a servo would cut it. How big/heavy are the targets? Could you, rather than lying them flat to the floor/lifting them up, rotate them through 90 degrees? Or is putting any of the mechanism in the line of fire a baaaad idea?

A linear-actuator ( a solenoid perhaps ) might work. It could push the targets upright and then just let them fall back down when it’s turned off.


#3

Many thanks for your recommendations - I’ll take a look at the Beetle!

The targets would be about 20cms square and would be plastic to start with, I thought I would put a spur on the mounting arm to lift and drop them (they should also fall when hit). I couldn’t find a solenoid that looked like it would be work (although my knowledge of solenoids is limited to little more than how to spell the word).

As you suggested, anything in the line of fire, is not a great design! (which would include cables!)

Thanks again and I’ll update this thread on how I get on!


#4

sorry I missed the summoning a few months back. Yes, I would highly recommend the Bleetle for most arduino based projects requiring BLE.

That said I have no experience inter-operating them with Rpi. I suspect their USB BLE-Link might be the best bet to communicate between them, and It seems there are some users that have had success with it: http://www.dfrobot.com/index.php?route=product/product&product_id=1220&search=USB+BLE+Link&description=true#.VjT-e19FuwA

that said, as much as I love me Bleetle, I am not clear on how or why you’d reach for one in this case, wouldn’t be more flexible to fit the Pi with a RasPiO Duino and access the Pi remotely? sorry if it’s a dumb suggestion, I’m not sure what the project limitations might be.


#5

hi
have u been able to make the pop up target system ??
pls do share
thanks