OK my subject is a little misleading, but only a little. What I wanted to do was get opinions in that DT might take notice of (or maybe they already have).

As I see it there is 2 current ways of expanding a DT80/85:

1. Analog MUX and drive this from the digital outputs (cheap, but code to develop).
2. Hang a DT5xx/8x etc off the serial sensor channel (costly, complex code).

I see four ways that DT might deliver dedicated expansion in purple:

1. New DT analog MUX with seamless interface (cheap?).
2. "Smart" expansion, linked via Ethernet/serial/SDI-12 maybe (cost more, but opens up longer cable lengths, wireless links etc).
3. Hang a DT5xx/8x etc off the serial sensor channel but with the code built in (costly, but same possible advantages as 2 plus redundancy of sorts).
4. Network multiple loggers (everything from 3 but oh my goodness, look at those $$$$$).

My personal tech preference is #2, but when it came down to laying out money I wonder if I would just go the cheapest route that actually works.

Anyone got other thoughts or brilliant proposals?

SuperMono

Good afternoon SuperMono,

To add my little bit. Being a bit of a Techno Geek I would personally like to see a smart expansion unit. One we have the channel expansion unit on an Ethernet connection distance become a non issue.

For example if the units were NTP enabled we could then put the CEMs any where. One CEM in Melbourne, one in London, One in LA etc. and they would all read at the same time.

The cost would be higher and development time greater but the flexibility of a not being tied to a length of copper cable. My views only, but I don't make the decisions.

Cheers,
Roger

Hi SuperMono, Roger, all.

By "Smart" expansion I gather you mean has intelligence whereby the slave unit can be sent commands and respond to the DT?

I am developing such a device out of necessity - DT, while exceptionally powerful and a fantastic product, is a pig on power consumption so needs to be put to sleep to save power (where no mains power is available) but is incapable of processing fast counts while asleep.

My project will continuously count wind speed and perform a rolling average while storing gust values until commanded by the DT with a digital output, to stop and send the data serially (all counts then reset, start again, etc,).

Wind direction is also catered for with a rolling average also processed, additional analog channels could be added if the box was expanded (currently one quad opamp takes care of 2 wind instruments' speed and direction while the processor handles the math and serial output/dig input). A 2x16 LCD gives continuous indication of values.

The beauty of all this is the sample period is set by the request rate from the DT and the slave draws only 4 mA allowing the DT to sleep for as long as required, wake, do its analog things and then get the serial data from the slave - all in a blink then resume sleeping...

The DT will basically be used only for modem/comm access and data storage/display.

It can be done - what do you think so far? The code is already written and a PCB design knocked up but I haven't had the time to make a prototype to test yet. Soon maybe!

Cheers,
Bill

Hi Bill,

U must be brilliant.. why don't u try selling that to DT or even make it a 3rd party product. Power hungry? so u are putting it to sleep so u can save power? If u wanna use the DT only for "..modem/comm access and data storage/display.." then u must be wasting a whole lot a $$$.

If u are brilliant to be doing the prototype then a simple modem control via serial ports, an LCD and an SD/MMC should be easy for you...

Anyways.. out of curiosity.. what do the guys at DT hafta say bout Bill's idea?

jn_marinengineer

Good morning jn_marinengineer,

There are a number of people who make add-on for our products. Some to fill very specialized needs while others are more general. For example we have a couple from Pacific Data listed in the FAQ under third party products.

We are always interested in what people would like in a new product and that is part of what this forum is about. And yes the ideas are passed on to management and engineering.

But there is a big step between a prototype and a fully commercial product. There also needs to be the volumes to make the product viable. If people have developed small modules and add-on then please let us know and may be even supply us with a sample to evaluate it.

Cheers,
Roger

Well I promoted a little discussion, which was my intention in the first place.
I understand the points made by Bill and Roger, using something like a PIC or similar micro is OK for a specialist task, but difficult to build as a general purpose 'super interface'.

I've just been looking at a couple of jobs and in one case a simple analog mux would be fine and suit as the application is cost sensitive, in the other the performance and flexibility of having something a bit more 'intelligent' would be more important than the difference in price.

So horses for courses, I need/want both.

Hi jr_marinengineer,

Thanks for the compliments but I don't consider myself brilliant, far from it...

Yes, I'm doing this to run a DT from solar power in locations where the size of the panel is limited and in places where wet season has very dark clouds for days on end.

dataTaker are smart enough to do what I'm doing without me selling the product to them, but the concept is good and one of these days I will offer all of my designs for whoever has the need. For the moment I'm busy enough making solutions for problems that seem to arrive almost daily.

I don't consider the $$$ wasted in purchasing the DT - it is a very capable instrument indeed, just uses too much power. I spent many years in the marine industry with remote instrumentation that had to run from batteries so mA and sleep states are important to me still.

I wasn't going to mention the microSD with DOS file structure, USB comms, graphic LCD, multi UART, multi speed, multiple interrupt and analog/digital IO possibilities yet, but now that you have... Hey, SuperMono, who said making a "super interface" was hard with a PIC? You're talking to the wrong people.

Don't worry DT I'll still buy loggers because they are still the best bang for the buck in my opinion, your service is excellent and it is not my aim or intention to compete. But you do need to address the power consumption issue.

Kind regards to all and no offence intended.
Bill

Hi Bill,

No offence take at all. It nice to see some good spirited debate happening on the forum rather than simple question and answer.

This is all really good feed back and I do pass it on.

Cheers,
Roger

On the PIC or any other micro being hard, I meant the user interface (Host Software) requirements more than the hardware and dedicated firmware. The more dedicated the design to a particular application the simpler (or even non existent) the user interface can be.

Bill, got a link for the microSD with the lot? Sounds interesting.

Sure, try...

http://chipdos.com/ for the blurb and...
http://www.sparkfun.com/commerce/product_info.php?products_id=8215 for the purchase. Let me know how you go.

Bill

Hi Members,

I'm back after a 3 year absence due change of employer and location - I'm now in the Middle East for at least another year.

I just wanted to let you know SuperMono and anybody else interested I have completed the prototype wind speed/direction slave but no longer have a use for it until I return to Malaysia and take up active use of DT's again...

Note: I could not access as user wjs so have re-registered as wjsm.

It's nice to be back on the Forum again and I will keep an eye open with a view to help where I can or keep my finger on the pulse until I have a DT80 in my hands again. I have some applications in mind but these are for personal use and not my employer unfortunately.

Kind regards,
Bill

Hi Bill,

Welcome back. There have been a number of changes here over the last couple of years and the DT80 has been coming along in leaps and bounds.

Looking forward to your input into the forum.

Cheers,
Roger