sorry, you are right, i
sorry, you are right, i never got my ping to work at those ranges though…
Now we’re getting somewhere
Now we’re getting somewhere (well you lot are), i like the idea of this - any thoughts of where it would be possible to find a directional antenna ? Cheers.
Hmm, the problem with your
Hmm, the problem with your typical reflective ultrasound is that there’s no real way to tell which object is your intended target. Has anyone ever tried using a discrete transmitter and receiver pair? The target could have an ultrasonic transmitter in their pocket, and the bot would then ‘home in’ on the broadcast signal using a sweeping ultrasonic scanner, or a pair/cluster of receivers. You could even encode a password into the broadcast signal as some sort of basic ID check.
Theoretically you’d also get twice the maximum distance from the usual hardware, since the ultrasonic pulse only has to travel one way, not to the target and back again.
You might find it’s easier
You might find it’s easier to just make one from some schematics on the net. They use them in ‘Amateur Radio Direction Finding’ events and for tracking tagged wildlife etc.
they also don’t seem to be
they also don’t seem to be too costly http://www.rainbowkits.com/kits/sdf-1p.html
The above one is quite big though, but you get the idea…
But maybe you could use a
But maybe you could use a simpler solution : you carry several IR leds as a beacon and your bot has two IR receivers to seek it, and you use the ultrasonic rangefinder just to be sure your bot stay at a safe distance…
Thanks, but would that work
Thanks, but would that work reliably in both light and dark conditions i.e. in sunlight ?
You’re right, i have to stop
You’re right, i have to stop thinking only indoor…
Maybe with a strong beacon? But i don’t think so…
(jeez, i just keep being wrong on this thread!)
No thanks for your efforts !
No thanks for your efforts ! I can’t believe how quickly people have contributed and replied, I’ve got so much food for thought now. Much appreciated.
The project is an
The project is an interesting one, it makes it easy to want to contribute =D
BTW Totoro, I almost suggested using an IR beacon + a pair of receivers too. You could modulate the IR signal to provide good sunlight immunity, but the main problem I thought of (just before I posted) was that it would be hard to get the bot to see you from all directions, unless you had several IR emitters over your body… I don’t think it would really work from an aesthetic perspective…
I would think so, with a
I would think so, with a pack of 5 ir emmiters I think it would be possible to get some good range. heck with a pack of 3 emmiters you should be able to get some decent range…even in sunlight.
As mentioned before, you
As mentioned before, you could use a grouping of 5 with one central and the other surrounding emmiters flowering out. this would give a slightly wider coverage. Since the design is to follow you, I would imagine that one direction should be good, maybe with a 3pack of emmiters to cover the sides just in case. As far as the following part, 3 sensors would give low resolution, but it really depends on what you are looking for. 5 would give you some pretty decent resolution as well as giving a bit more coverage.
just my 2 Cents…
If you plan on going this
If you plan on going this way you could use LED strips, maybe tape them to a waist. If needed you could lens them to output a narrower beam. (i do that for my lasertag project so if you need help just ask)
Mummy where are thou
You could have the following setup.
1) The robot sends an ultrasonic pulse at a certain frequency (it’s basically yelling ‘MUMMY WHERE ARE YOU?’. This pulse will take a certain time to travel to the receiver of mummy
2) Mummy receives this message and …
3) responds by sending an ‘I am here you little twit’ back (same distance, same time lapse).
4) twit receives the signal and calculates the distance to mummy. If distance to big, than move, if too small then just stop/slow down.
If 2 doesn’t happen then mummy is out of range and the robot has to stay put. (mummy is in the shop just wait until she’s back).
I am not sure about the directional stuff though …
YCD
P.S. Sigh… replied to the wrong message in the string… sorry
I am doing the same type of project
My TOBI will do something similar that you are wanting to do. I am going to be using 3 Ping)))'s and two IR on sweeping servos for distance detection, object avoidance and keeping the proper distance behind me or the next TOBI [in the chain] that it is following. For homing in on me, I am planning on using a Thermopile, IR Beacons and RF for getting a heading of my location [2 out of 3 provides a heading]. For the RF part I am going to use an array of 4 antennas that measure signal strength with reflectors to affect the signal.
My page is here: https://www.robotshop.com/letsmakerobots/node/7025
A similar project is here: https://www.robotshop.com/letsmakerobots/node/8527Nice bot and very nice page!
Nice bot and very nice page! Thanks for the info…
Got a feeling from your trials and tribulations that this is going to be a little more involved than i first thought - A challenge no less !
Hi all.I have managed to
Hi all.<o:p></o:p>I have managed to find circuit diagrams for both an ultrasonic transmitter and receiver. Unfortunately I have little to very little knowledge of electronics and have a few questions regarding the circuit if anybody has time to have a peek.<o:p></o:p>The circuits
http://www.reconnsworld.com/ir_ultrasonic_ultraswitch.html <o:p></o:p>I think the circuits may be a little old as I am struggling to source the SL100 NPN & SK100 PNP transistors, will there be an alternative to these?
Also the relay is stated at 6v 200ohms I can only seem to find 6v 100ohms, will this be ok?
And finally the 560n ceramic capacitor, I also can’t seem to source this - would the closest to this suffice?<o:p></o:p>Maybe someone has an ultrasonic transmitter and receiver circuit diagram already that they could share with some more readily available components?<o:p></o:p>Thanks for any help !<o:p></o:p>
• Plenty of alternative
• Plenty of alternative transistors will work for driving the emitter speaker
• The 100Ω relay will just consume more current, but will work the same
• That capacitor just looks like a filtering capacitor, anything in the neighbourhood will do the job
There are several pre-made ultrasonic units on the market, they may be more useful to you than trying to build your own, especially if your electronics skills need touching up. Have a poke around LMR and a few robotics parts stores and check out the options.
im pretty sure you can make
im pretty sure you can make a system that follows humans heat signitures cant you?
or maby have an infra red beacon on your shoe that it follows? also i think humans emit IR light from heat aswell if im not mistaken. supose you could look into that too
grim