Hall Effect Sensor?

[David Schwab]

Joe, not sure what you mean about it not being AUD $60-$100. If you look at my post above, you'll notice that it is the total cost including shipping and the international processing fee. I recalculated it today and the total is AUD$72.59

When I do the conversion from USD$31.32, I get AUD$39.736.

[mkat]

When I do the conversion from USD$31.32, I get AUD$39.736.

That's what I got too:

CUB3: USD$31.32, AUD$39.74
Shipping to Aus (USD$18 - $32 depending on destination, estimate only): USD$20, AUD$25.24
Processing fee on all international orders except Canada: USD$6, AUD$7.57
----------------
Total: USD$59.32, AUD$72.55

[Joe Gwinn]

Joe, not sure what you mean about it not being AUD $60-$100. If you look at my post above, you'll notice that it is the total cost including shipping and the international processing fee. I recalculated it today and the total is AUD$72.59.

Hmm. I see that I misread your posting.

Also, the cheapest shipping Digi-Key offer is via United States Postal Service Global Express Mail @ USD$18. As you say, shipping in bulk may be cheaper, but it's relative. There is no way we're are going to get it cheaper than that (shipped to Australia) from Digi-Key. Local to the US is cheap for this product, not here.

The point being made is that shipping and handling is partly per-order, not all per-gram, so it makes sense to make fewer but larger orders.

I agree with this [about local sources] to a certain extent and possibly in this case. But, what I've seen, is that it is rare to get a really good deal here at all.

That's what I've heard too, so while parity with sources on the other side of the world will never be achieved, one can greatly reduce the impact.

War story: In the 1970s I worked in Sweden on and off, and then for a year. On 12 December 1973, I bought a HP-45 calculator in the US, for $400.00 (which is $1,816 in 2007 US dollars). Shortly after arrival in Stockholm, I went to some kind of industrial show, where the local HP Rep had a HP-45 on display, held down with a clear plastic collar bolted to a heavy podium. The price seemed a little high to me. The claim was that this was due to shipping. I did the exchange-rate conversion on the HP-45, and determined that for the difference, one could fly from Stockholm to New York, run into the city and buy a HP-45, run back to the airport and fly back to Stockholm, and be money ahead. The Swedish price was about double the US price. Oops. The nice salesman was not happy with me. My business partner was laughing through the whole episode. This kind of gross overcharging was typical in Sweden.

I have a quote for a HP-65 from HP Sweden, in Stockholm, dated 18 March 1974. The quoted price is 5,275 SvKr (excluding taxes), and the then exchange rate is 4.67 SvKr per USD (hand annotated by me on the quote), so this is USD $1,295.55 (1974 dollars). At the time, the US price was USD $795, so the ratio is 1129.55/795=1.42. Only a 42% markup from US retail price. At least it wasn't 100%. We didn't buy the HP-65.

[mkat]

There are hall sensors (from Allegro and others) that contain the necessary logic and yield a binary output signal, well suited to driving a counter (if the voltage levels are matched).

What about the counter debounce with a hall sensor, will this come into play as with the reed switch? Can you provide more info on an appropriate sensor for this kit?

[Joe Gwinn]

What about the counter debounce with a hall sensor, will this come into play as with the reed switch? Can you provide more info on an appropriate sensor for this kit?

There is no bounce with a hall sensor, and counters like the CUB3 are pretty tolerant anyway. The key is the minimum pulse width that will register: It needs to be no shorter than five or so milliseconds. This will allow reliable counting with a reed switch, and if a counter can handle a reed switch, it can also handle a hall sensor (assuming you are using one intended for this purpose, not a linear sensor).