Smart breadboard

[Andy Burns]

Plug in components and then "wire them up" in software

[John Rumm]

Mice...

How much I wonder?

[Andy Burns]

Rats ... £250

[Andy Bennett]

I would be very wary about using this for analogue experimentation and if playing with digital an FPGA is cheaper.

[Andy Burns]

When I looked earlier, I though it said the crosspoint switch chips were

75 milliohms, but it turns out to be 75 ohms which I'd have thought would cause havoc with many circuits?

[Andy Bennett]

Agreed, plus the leakage currents and crosstalk will be problematic in the analogue domain.

In summary I think it's an expensive inferior solution looking for a problem.

[Brian Gaff]

. Playing on words here, is this what is called using your loaf. #why have any hardware at all, there used to be software where you could draw a circuit complete with symbols then run it and be able to see what it does etc. The main reason for breadboarding would be to check any problems with interaction between normal sized components etc. Then I guess your original software would have been able to produce the mask to make the pcb. Brian

[alan_m]

It could also be a very expensive fuse if you accidentally try and pass too much current. Program in the wrong link and watch for the magic smoke.

[Theo]

If it's successfully shorted 12V, the current will be 160mA. The developer says they've successfully run 200mA through a connection for minutes, which have a max rating of 100mA per chip and 15mA per connection. They also say the switch chips are easy to change with a hot air gun, and offer to supply spares in the box. The CH446Q chips are $1.76 to buy.

A neat move would be to mount a temperature sensor under each chip and shut things off if they are getting warm.

Theo

[alan_m]

So the developer has done 5 minutes of testing and run a one junction at

12x it's specified rating. Does that switch now operate with the same insertion loss and speed etc. What happens if you overrun more than one adjacent switch in the package?

So, not only do you have to have the skills in designing but also the skills in changing 44 pin surface mount components without damaging the PCB that they are attached to.

It all depends what gets shut off.

I have the T shirt from 40 years ago where completely shutting off the

+ve supply to a VERY expensive IC that required a +ve and -ve supplies caused the magic smoke. Having too much complex protection can actually be worse than having no protection at all. Much like having a Built In Test (BIT) that is more complex than what you are trying to monitor is likely to have more bugs/faults than the rest of the design.

BTW, the on resistance of around 65 ohms is only when the power supply is at its maximum value. Take the supply to around 5V (as for a typical battery supply) and the on resistance is more like 180 Ohms rising to

225 Ohms as the chip temperature reaches 85C.