HP-41 GPS Module - True or fiction?

[Ángel Martin]

(11-07-2016 10:53 PM)Valentin Albillo Wrote:  Back in the 80's, a number of HP calc fans, myself included, used to gather late in the evening in the Ateneo de Madrid building, to show off our 41's and new synthetics and such to one another, and discuss anything and everything HP-calc related.

Ah the Ateneo... I was there just a few weeks ago reminiscing about the good 'ol days ;-) Unfortunately not back when you saw that black swan!

(11-07-2016 10:53 PM)Valentin Albillo Wrote:  Among those people there were some that worked at HP and/or had some insight as to new products, modules, etc., and lo and behold, at one of those gatherings someone wished to show us all an HP-41C fitted with a beta GPS ROM module.

We gasped in amazement and tried it, watching the coordinates in the display and even considering taking it for a short walk to see the display change accordingly and such. Everyone was quite impressed though it would lose the signal at times and required careful positioning within the Ateneo for optimum signal reception.

If it weren't coming from you I would think this to be a belated April's 1st. (or an early December's 28th ;-) joke, but I fully acknowledge the veracity of your report. Wow! I'd guess that was a Corvallis prototype and not a local variety, but it's uncanny it never got sighted or reported elsewhere.

(11-07-2016 10:53 PM)Valentin Albillo Wrote:  Perhaps it was some elaborate joke but I don't think so, no one seemed to be making any lame attempt at humour and the fact that it was an experimental, beta product with still many rough edges was made perfectly clear.

Perhaps it existed but was never released and eventually abandoned. Anyway, I saw it that one time, and never again...

Maybe the issue was related to accuracy or signal stability. I'd imagine there could have been issues with the circuitry used back then, but still it's a wonder that it would have fit into the reduced constrains of a 41 module.

Honestly I don't see how this is not eliciting more interest amongst the forum readers - it's got to be relatively simple to develop and the idea is hands-down superb...

Best wishes,
Ángel

[4ster]

(11-07-2016 10:53 PM)Valentin Albillo Wrote:   
Hi, Ángel:

(11-06-2016 03:49 PM)Ángel Martin Wrote:  Well, fiction so far... but the question is could it be done?

I wouldn't be so sure about the "fiction" part.

Back in the 80's...

Among those people there were some that worked at HP and/or had some insight as to new products, modules, etc., and lo and behold, at one of those gatherings someone wished to show us all an HP-41C fitted with a beta GPS ROM module.


Best regards.
V.
 

I'm a little light on my history but I recall that Corvallis Micro Technologies (CMT) was started by ex-HP Corvallis engineers. They made at least 2 products that plugged into HP-41 ports, the CMT-200 Data Acquisition and Control unit, and the CMT-300 Multimeter. As the market changed they started making Field Data Recorders for harsh environments, the MC-V was a staple in the forest industry in the Pacific Northwest. The MC-V morphed into the MC-GPS, a very capable mapping grade GPS receiver. One of the options for the MC-V/MC-GPS was HP-41 emulation firmware.

Speculation: Perhaps CMT was experimenting with GPS in the late '80s and you saw a very early version of CMT's work on the 41.

More on topic:
Instead of trying to fit a GPS receiver and antenna into a module, how about using a defunct card reader case? It would provide better options for an optimal antenna mount and provide more room to fit the GPS engine, including space for a separate battery for the GPS.

[Ángel Martin]

(11-08-2016 03:51 PM)4ster Wrote:  Instead of trying to fit a GPS receiver and antenna into a module, how about using a defunct card reader case? It would provide better options for an optimal antenna mount and provide more room to fit the GPS engine, including space for a separate battery for the GPS.

Not a bad idea either, I'd go for it either way - although if the HP-25's GPS can manage without a card-reader sized extension one wonders why wouldn't that also be applicable to the 41's. Of course it might well be there are reasons to make it more reliable or stable, I wouldn't really know...

[Garth Wilson]

Heck, if you're going to use a card-reader shell, you could put a graphic LCD in the top too. I got a working card reader on eBay a few years ago to put an MLDL2000 in it, and then found out the MLDL2000 is more or less obsolete because of NoV64 not to mention 41CL. I have two tape drives, and I've never had a tape failure. What do I need a card reader for. (OTOH, what do I need a GPS for. I'm all for extending the life of the 41 with new technology though.)

[hth]

(11-08-2016 07:38 PM)Garth Wilson Wrote:  Heck, if you're going to use a card-reader shell, you could put a graphic LCD in the top too. I got a working card reader on eBay a few years ago to put an MLDL2000 in it, and then found out the MLDL2000 is more or less obsolete because of NoV64 not to mention 41CL. I have two tape drives, and I've never had a tape failure. What do I need a card reader for. (OTOH, what do I need a GPS for. I'm all for extending the life of the 41 with new technology though.)

A bit off topic, but I found the MLDL2000 to be the perfect companion for testing MCODE on the HP41 hardware. It has RAM pages and a USB port! Just hook it up to the computer and download images in virtually no time. No need for serial ports, flashing, HPIL or whatever, just hook up the HP41 using USB and run MCODE. You do not even need to disconnect it!

Håkan

[Luigi Vampa]

(11-06-2016 05:15 PM)Otto55 Wrote:  Sounds like an application waiting for the DM42 with its USB port.

It is clear a GPS module for the HP41 could be an interesting project just either for the fun of it, if you love electronics and calculators, or simply to increase the number of optional modules for such a venerable machine.
[OFF TOPIC] Nevertheless, I wonder whether the prospect price of the DM42P (ca. $275) would be no stopper for a pro, like a surveyor. If the latter model gets a plain USB to talk with an inexpensive external GPS USB module, wouldn't it be of interest to today's surveyors? I am sorry to think out loud in solo-brain-storm mode, I am an absolute ignorant about Civil Engineering :O.

[Otto55]

(11-08-2016 10:14 PM)Luigi Vampa Wrote:  ... the prospect price of the DM42P (ca. $275) ...

The last figure I remember was 250€ - let's wait for Wall Street tomorrow.

[Csaba Tizedes]

Just an idea:

If you have a problem with the GPS modul thickness you can use the ports 1+3 OR 2+4 together. You will loose one port but maybe you can fit all the parts inside. The required double thick box probably can be manufactured with 3D printing.

Csaba

[Ángel Martin]

(11-08-2016 08:23 PM)hth Wrote:  A bit off topic, but I found the MLDL2000 to be the perfect companion for testing MCODE on the HP41 hardware. It has RAM pages and a USB port! Just hook it up to the computer and download images in virtually no time. No need for serial ports, flashing, HPIL or whatever, just hook up the HP41 using USB and run MCODE. You do not even need to disconnect it!

100% agree! Nothing beats the feeling of editing the MCODE in real time ;-)

[MeindertKuipers]

Thanks for the enthusiasm for the MLDL2000. I might almost be tempted to realize a new version ....

As a proof of concept I made the HP41 (with the MLDL2000) to interface with SD cards, USB sticks and the internet itself (loading a ROM image from a website), so getting a GPS connected would be trivial. A serial port was also used for communication. I must admit that I did connect an ARM based controller to the MLDL that actually did the hard work, but it worked quite well.

The demo I did is still on youtube.





Today, this would all fit in a cardreader housing, with wifi, bluetooth and the so desperately needed GPS

Why there is no new MLDL version? I get a request to buy an MLDL about once a month, so there could be a business case. But all I can do on the HP41, I can do much better on my phone, and although it is truly fun to create all the modern stuff to support the good old '41, the energy to put into a project like that is also well spent on many other fun aspects in life. If someone wants to take up the challenge to design and produce the hardware, I will gladly share experience and support this project.

Regards,

[Massimo Gnerucci]

Astonishing, Meindert.
So... when will we have a new MLDL version?

[Ángel Martin]

(11-10-2016 05:25 PM)MeindertKuipers Wrote:  The demo I did is still on youtube.

Mind blowing demo... what do we have to do to make you change your mind about not making it happen? Will serious arm twisting do? ;-)

[Michael Fehlhammer]

We have to convince Meindert by setting up a preorder list.

I'll take five of these super-MLDLs.

When the list counts above 100, we have a chance that it might be realized. :-)

[Ángel Martin]

(11-10-2016 05:25 PM)MeindertKuipers Wrote:  I must admit that I did connect an ARM based controller to the MLDL that actually did the hard work, but it worked quite well.

Would it be possible to get it done without the ARM controller (which I assume increases the current demands?), I guess I wonder about the additional complexity of either option, not sure what's the simpler approach. Imagine the SD slot into a module case... dream time again?

Also how much software did you have to write to get the communication to happen at the point where you took it - which looks to me quite well along to a complete solution, judging by the file handling it does/did.

Cheers
'AM

[MeindertKuipers]

This project was done as part of a design challenge, and all information is online:
http://circuitcellar.com/contests/nxpmbe...DE3668.htm
I won a little pat on the shoulder with it, and the amount of software was really not too bad, thanks to the various libraries that were available.

For handling the file system, USB and network I do not think it is an option to work without a microcontroller, and if power is a concern, it can be switched off when not needed.

[mfleming]

Here's a fun little project I've been playing with the past couple of months that at least provides GPS for the 41CL using its serial port. Something more along the line of the HP-25 ACT + GPS would naturally require a little more work!



Going clockwise in the above photo montage, the upper left photo shows the GPS assembly connected to an HP-41CL serial port. The 41 shows the menu of the GPS FOCAL program. The upper right photo is a close-up of the menu, with labels for Time, Latitude, Longitude, Altitude and number of Satellites. The photo below is the 41 reading back the Latitude string and processing the result. The photo below that is the latitude in the X register, and the bottom right photo is the latitude string in the Alpha register. The result for the commands is always returned in the X and Alpha registers.

The final lower left photo shows to scale some parts that might actually bring to life a GPS module for a regular HP-41. As shown by Maximilian Hohmann in a previous post, a printer module shell might hold a smaller GPS module. The board in the picture is a Teensy 3.2 SBC that might do the needed transformation from 41 I/O bus to GPS module.



This montage shows the top and bottom view of my current assembly. It consists of a Maxim RS232 interface chip, an Arduino Pro Mini SBC, and a Ublox M8N-based GPS module. All components are through-hole for easy soldering. Both the Arduino and the Ublox M8N GPS module are cheap and easy to find on TAS. Three AA batteries provide power to the Arduino, and it supplies regulated 3.3V power to the GPS module.

The logic analyzer display on the bottom shows a key contribution the Arduino makes; proper serial communication with the 41CL board. A ten millisecond delay is introduced between reception of a command from the 41CL and the sending of results. The delay is needed for the time needed between the YEXP call sending a command and a YIMP call capturing the result. A four millisecond delay between bytes sent is needed to avoid serial port overrun. Perhaps the 41CL v5 board could provide serial input buffering via a deep FIFO?

I think in the last and final iteration I'll go for the smallest feasible board, with perhaps the footprint of a four AA-cell battery holder in a 2x2 stack arrangement. Use a Teensy LC SBC for easy programming via USB port, and a GPS module of any sort mounted separately. The GPS module I'm using is battery backed for quick re-acquisition when powered back on, and can be programmed to log position, heading, speed, etc. Might be interesting to dump a log of my morning walk to a 41CL RAM page, but I'm stumped at the moment as to how I might show Google Maps on the 41 display

~Mark
(Well, not surprisingly, inserting a google drive image doesn't work, so I'm back to using attachments!)

[Ángel Martin]

Amazing... way to go!

I tell you what, you complete the project and I'll see to the GoogleMaps UI, and will throw in a Pokemon_GO applet as well ;-)

Seriously, hope to see the final result - will love to have one of those if they ever become available.

Cheers,
ÁM

[Dave Frederickson]

(06-27-2017 01:28 AM)mfleming Wrote:  (Well, not surprisingly, inserting a google drive image doesn't work, so I'm back to using attachments!)

Did you try Permalinks?

http://www.hpmuseum.org/forum/thread-173...l#pid30656

Dave

[mfleming]

(06-27-2017 08:15 PM)Dave Frederickson Wrote:  Did you try Permalinks?

http://www.hpmuseum.org/forum/thread-173...l#pid30656

Dave

Yaayy! Thanks Dave!

Not to worry Ángel, but I think you'll be appalled by how slow it is in FOCAL using YPEEK and Alpha register operations. Stay tuned for the next iteration...

~Mark (waiting for Pokemon)

[rprosperi]

(06-27-2017 09:43 PM)mfleming Wrote:  Not to worry Ángel, but I think you'll be appalled by how slow it is in FOCAL using YPEEK and Alpha register operations. Stay tuned for the next iteration...

Once the design is stable, I wonder if there is anyone around that could translate a slow FOCAL program to MCODE....