Re: [beam] Nv/Nu
> Barry Michels wrote:Hi, Barry.
> I've just recently gotten started in BEAM. I've been interested in
> robotics all my life, but haven't built any because of my budget. Now
> that I've found BEAM, I've built a working biocore, but haven't made
> it into a walker yet. I'm glad I kept a junk box even when my parents
> tried to get me to throw it out!
> Anyway, I was wondering what the difference between a Nu and Nv was.
There are two "flavours" of each neuron. I'll discuss grounded neurons
Schematically, both neurons have the same 3 components -- capacitor,
resistor, inverter. One lead each of the capacitor and resistor connect
to the inverter input, but ...
Nv: neuron input is to the capacitor. Resistor is grounded.
Nu: neuron input is to the resistor. Capacitor is grounded.
Functionally, the neurons behave very differently.
Nv: - off condition is a high output.
- a rising transition at the input causes the neuron
to fire (switch on) instantly.
- after a delay, the neuron switches off.
- OR, "on" first, then a delay, then "off".
Nu: - off condition is a high output.
- a high input causes the neuron to fire -- after a delay.
- the neuron remains on as long as the input stays high.
- OR, delay, then "on", stays "on".
The other "flavour" of each neuron involves connecting the resistor or
capactior to Vcc instead of ground. In this case, input and output
conditions are the reverse of what I just described.
The Nu neuron is potentially a very complex device because you can have
multiple inputs, each with a separate resistor, and you can put diodes
in series with the resistors to create separate "on" delays and "off"