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From: Bill BiggeSent: Sunday, November 17, 2002 11:35 AMSubject: RE: [beam] bi-lateral switchesSo, when can we expect to see Solarbotics stocking them?
In fact it might help matters if there was a basic bot design that demonstrates their use, I mean in the way that a 2 motor walker demonstrates Bicore use and a photopopper demonstrates SE use.
Any ideas? – I’m keen to get some more ‘advanced’ beam circuits like the BEAMAnt ones I did, produced as PCB’s.
Incidentally, I can’t remember if I posted this before but I have a short(ish – 5.75Mb) video clip of the advanced BEAMAnts I made a while ago:
http://www.cogs.susx.ac.uk/lab/adapt/aslab/robotgallery/movies/BEAMants.MOV
Bill
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Bill Bigge
Autonomous Systems Lab
Cognitive and Computing Sciences
Pevensey-II
Sussex University
Brighton +44 (0)1273 877621
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www.cogs.susx.ac.uk
-----Original Message-----
From: Wilf Rigter [mailto:wrigter@...]
Sent:17 November 2002 19:30
To: beam@yahoogroups.com
Subject: Re: [beam] bi-lateral switches
I am a great proponent of using these devices because they are the simplest, most Beamish of all CMOS ICs. Bilateral switches are the closest thing to simulating a mechanical switch or relay contact. Most people don't realize that the bilateral switch, aka transmission gate or analog switch or mux, is the most common building block inside logic ICs. The CD4016 quad bilateral switch was used as the original "reverser" circuits for microcore designs.The CD4016 is obsolete but the improved 74HC4066 is alive and well.
There are some variations configured as multiple pole analog multiplexers like the 74HC4051,74HC4053 and 74HC4053. Of all 74HC ICs the bilateral switches are the only ones rated at Vcc=12V. I have used these parts in a number of BEAM designs that didn't get much attention probably because not many people have these chips on hand. If there was more interest, it would open the door to improved versions of almost every BEAM circuit and countless new BEAM designs. These are the basic elements of more complex analog switching networks such as 8x8 crosspoint switches with memory at each node.
wilf
----- Original Message -----
From: Bill Bigge
Sent:
Sunday, November 17, 2002 8:29 AM Subject: [beam] bi-lateral switches
I bought a few 74HC4066’s the other day. These are called ‘bi-lateral switches’ and, in very simple terms, are a bit like an electronic relay, i.e. you can activate them and they will pass current in either direction.
I’m mentioning this because they might have some neat uses in BEAM robots. I wired one up to a pair of bicores so that the two bicores were coupled with 1M resistors in parallel with the BiSwitches. This meant that when the switches were off the two bicores were coupled with the 1M resistors and when the switches were on they were coupled directly – with a resulting change in behaviour.
I also tried a circuit with a grounded bicore with all the grounding resistors going to a BiSwitch, again with another resistor bi-passing it to ground – this made a ‘two speed’ bicore so by activating the switch the resistance to ground was decreased and the bicore speeded up.
Although I haven’t worked out any practical applications in robots for this device it seems like it could be quite useful for getting more complex behaviour out of robots – actually, thinking about it you could apply them to a BEAMAnt as a way of altering the phototropic behaviour – you could switch between low and high PCore resistors to reduce or increase the amount of attention the bot pays to light sources – the switch could be activated when the battery or capacitor charge drops below a certain level.
I imagine there may be some useful applications in learning circuits as well . . .
Bill
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Bill Bigge
Autonomous Systems Lab
Cognitive and Computing Sciences
Pevensey-II
Sussex University
Brighton +44 (0)1273 877621
-----------------
www.cogs.susx.ac.uk
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