HP-41 GPS Module - True or fiction?

[Ángel Martin]

Well, fiction so far... but the question is could it be done?

I'm inclined to say yes, considering the impressive GPS tricks our Woodstock's resident expert PANAMATIK has achieved on his own, see the link HP-25E GPS ACT Version

It would be cool to read the lat-lon data on the 41 display, and even cooler to use that information in your navigation programs...so am I alone wishing somebody with the right wits should undertake this project?

Hey we could even write a version of Pokemon-GO with this module plugged in ;-)

[Bill (Smithville NJ)]

Hi Angel,

GPS with the HP-41 - very interesting idea.

I've been using a GPS kit to calibrate the frequency for a QRP ham radio transmitter. While this kit board is too large for a module, it might be a cheap way to play around with. It is really sensitive - I get 3D satellite signals inside my house. See following link:

GPS Receiver Kit

For any Ham Radio members, you might want to take a look at some of the other kits on the site. I've assembled most of them and can say they work great.

Bill
Smithville, NJ

[Otto55]

Sounds like an application waiting for the DM42 with its USB port.

[Maximilian Hohmann]

Hello!

The easiest and cheapest way would be to connect an arduino board via HP-IL (IIRC someone posted the necessary code here some time ago) and attach a GPS module to that. All that in a little box with a (rechargeable) battery should not cost more than 20 Euros/Dollars for the parts.

But what for? The HP-41 can hardly fit the longitude into it's display. My cellphone on the other hand, which cost a lot less than a good HP-41 these days, can display latitude, longitude, altitude, speed and one hundred more values including a moving map of our entire continent all at once. And provide a voice output of a nice lady talking Dutch (she has the most pleasant voice so I selected her...) who guides me home at night. Yes. At night, because that display is readable in the dark.

A GPS sensor for an HP-41 would have been an ultra-cool thing in 1980. Unfortunately, there was no GPS yet, then.

Regards,
Max

[Ángel Martin]

(11-06-2016 07:20 PM)Maximilian Hohmann Wrote:  But what for? The HP-41 can hardly fit the longitude into it's display. My cellphone on the other hand, which cost a lot less than a good HP-41 these days, can display latitude, longitude, altitude, speed and one hundred more values including a moving map of our entire continent all at once. And provide a voice output of a nice lady talking Dutch (she has the most pleasant voice so I selected her...) who guides me home at night. Yes. At night, because that display is readable in the dark.

I think that's an unfair comparison because it's a completely different ballgame; so while I acknowledge the quantum leaps in technology that doesn't prevent us from also enjoying the new tricks on old gadgets - remember, this is a MUSEUM forum!

So I contend the HP41 plug-in GPS module would be GREAT also today ;-)

[Maximilian Hohmann]

(11-06-2016 07:34 PM)Ángel Martin Wrote:  ... that doesn't prevent us from also enjoying the new tricks on old gadgets - remember, this is a MUSEUM forum!

Sure, I know :-) But attaching a GPS module, whose on-board processor alone has about 100.000 times the memory capacity and processing speed of an HP-41, is quite a violation of historic accuracy, isn't it?

What I would find more challenging is to implement the equations required to determine the geographic position (lat/long/altitude/time) from the pseudorange measurements of the GPS receiver on an HP-41. This would also require the almanac and ephemerides of the satellite constellation of course... If someone finds a way to fit that into an HP-41, I am going to be deeply, deeply impressed!

Regards
Max

[mfleming]

There's no shortage of small capable GPS units, like this little one:

http://www.sparkfun.com/products/13670

   

To quote the vendor

The GP-735 is a slim, ultra-high performance, easy to use GPS smart antenna receiver. With -162dBm tracking sensitivity and only 29 second cold start time, the GP735 is a tiny, yet powerful, piece of tech. The slim design makes it ideal for applications where you don’t have a lot of space to work in. Really it’s quite small.


At 35 x 8 x 6.5 mm, this can tolerate a 6V supply, but its TTL serial port has a 3.3V interface. Perhaps a battery-powered unit could be attached to the 41CL serial port using a proper level translator IC. Sort of an ultimate Time Module

Now if only something like this could be squeezed into a tall module case!

[Maximilian Hohmann]

(11-06-2016 07:43 PM)mfleming Wrote:  Now if only something like this could be squeezed into a tall module case!

That's absolutely no problem at all, size wise.

[HP-Collection]

I once built my own geocacher GPS when I was active there.... Very simple to do on Arduino.

[Paul Dale]

Most GPS module produce serial output. Shouldn't be difficult to hook up to a 41.


Pauli

[toml_12953]

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

I'm inclined to say yes, considering the impressive GPS tricks our Woodstock's resident expert PANAMATIK has achieved on his own, see the link HP-25E GPS ACT Version

It would be cool to read the lat-lon data on the 41 display, and even cooler to use that information in your navigation programs...so am I alone wishing somebody with the right wits should undertake this project?

Hey we could even write a version of Pokemon-GO with this module plugged in ;-)

There are GPS units that fit in an SD card slot. Is there an adapter to use an SD card with the 41?
Tom L

[hth]

(11-06-2016 07:42 PM)Maximilian Hohmann Wrote:  

(11-06-2016 07:34 PM)Ángel Martin Wrote:  ... that doesn't prevent us from also enjoying the new tricks on old gadgets - remember, this is a MUSEUM forum!

Sure, I know :-) But attaching a GPS module, whose on-board processor alone has about 100.000 times the memory capacity and processing speed of an HP-41, is quite a violation of historic accuracy, isn't it?

Regards
Max

Nah, all printers, computers, ... you name it, were peripherals to the HP-41 back then. Still is by the way, and will always be...

Håkan

[Garth Wilson]

Compare to older airplanes which are still in service after decades, by having new equipment installed. The Wikipedia article on the B52 bomber says, "Even while the air force works on a new bomber, it intends to keep the B-52H in service until 2045, nearly 90 years after the B-52 first entered service, an unprecedented length of service for any aircraft, civilian or military." The Boeing 747 was introduced 46 years ago. The 41 may not have a color graphics "glass cockpit" yet, but it filled rolls that no other calc has filled even in modern history, and continues to be expanded with hardware and software contributions from illustrious members here.

[Maximilian Hohmann]

(11-07-2016 05:40 AM)Garth Wilson Wrote:  Compare to older airplanes ....

I understand that reasoning, but there is another side to that as well: Especially pilots of historic aircraft often refuse to use modern technology when flying their antiques, because at the time their open cockpit biplanes were built, there was no radio and no radionavigation either. So they only use what was available then: Stopwatch, map and compass.

As I am more a collector of calculators than a calculator user (the ones I need at work are integrated into the avionics...) I tend to see it that way to: I only want to connect stuff to my HP-41 that is contemporary with the machine.

Regards
Max

[Ángel Martin]

(11-07-2016 11:52 AM)Maximilian Hohmann Wrote:  As I am more a collector of calculators than a calculator user (the ones I need at work are integrated into the avionics...) I tend to see it that way to: I only want to connect stuff to my HP-41 that is contemporary with the machine.

You should see the GPS running on the HP-25 with a new ACT circuit, maybe that would convince you that there's nothing wrong with spicing it up with modern tools...

[Maximilian Hohmann]

(11-07-2016 11:56 AM)Ángel Martin Wrote:  You should see the GPS running on the HP-25 with a new ACT circuit, maybe that would convince you that there's nothing wrong with spicing it up with modern tools...

I didn't say there's anything wrong! And as I tinker around with electronics in my spare time (maybe to 1/10 of Panamatik's level...) I may one day put an Arduino board an a GPS sensor into a dead HP-21 or 25. But this will be a completely different calculator then. Only the keyboard and display will be original, the "heart and brain" of the machine, which made it a priced collector's piece, will be gone.

It is like restoring the Mona Lisa to modern standards by painting a contrail into the sky. This will certainly appeal to some who like the thought of bringing old and new together, but the majority of art lovers will burst out in tears.

Regards
Max

NB: Out of curiosity, I wired together a little GPS receiver with stuff pulled from my box(es) with parts. This is a minimal Arduino based solution using a 10Euro Chinese GPS module and an 8 digit seven segment display. The module outputs a serial ASCII data stream (NMEA), libraries for parsing that stream can be found plenty on the internet. It took a couple of minutes after power-up to get a fix, but it hasn't been powered for months. If I switch it on and off again now, it should get the fix within seconds.



To see if it will fit inside an HP-41 module, i put it next to a printer connector (I misplaced my box with real HP-41 modules... but I know I have it somewhere). This module here, especially with the external antenna, is probably a little bit too large:



But I have smaller ones too (the one here is for my quadcopter drone), the antenna is fixed to the back of the PCB but can be desoldered and placed anywhere. A module like that might just fit inside a normal module, certainly so if the antenna is mounted on the outside.







Processor-wise, all that is required are two wires, TX and RX for a 9600baud serial connection. An ATTiny chip could possibly be used for that, it comes in an 8pin DIL package and would have 4 digital I/O lines left to communicate with the calculator.

[Garth Wilson]

(11-07-2016 11:52 AM)Maximilian Hohmann Wrote:  

(11-07-2016 05:40 AM)Garth Wilson Wrote:  Compare to older airplanes ....

I understand that reasoning, but there is another side to that as well: Especially pilots of historic aircraft often refuse to use modern technology when flying their antiques, because at the time their open cockpit biplanes were built, there was no radio and no radionavigation either. So they only use what was available then: Stopwatch, map and compass.

I know, as our company makes aircraft communications equipment (I design the electronics), and yes, some of these aircraft owners want things battery-powered and not attached to the aircraft, whether it's for a J3 Cub with no electrical system, an ultralight, or whatever. One of our intercoms went into an aircraft Amelia Earhart flew, and they put the controls where you had to reach between the seat and the wall to work them, because they wanted everything modern to be hidden. For others, they have their hand-held GPS, hand-held radio, and other hand-held things, because they want their modern electronics but they want to keep the antique antique.

I was not talking about the sport planes though. I was talking about military and commercial jets that are still in combat service and daily passenger service. These aircraft have been outfitted with new electronics and improved engines; but the aircraft themselves are decades old.

[Valentin Albillo]

 
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, 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.

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.

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 (same happened with the HP-71B, we saw and played with one at one of those meetings months before it was finally announced and released).

Best regards.
V.
 

[TASP]

BTW, I recently had a ride on a Stearman biplane. I didn't realize at the time (too damn scared from height, flimsy looking wing bracing, wind blast and other aircraft I was sure couldn't see us) but the pilot wasn't even using a stopwatch, map or compass. We were following highways.

Also, it was hard not to notice cars on the ground were going faster than we were.

I certainly would have been impressed had he pulled out an HP41 with a GPS module !!!!


We did finally land, uneventfully, and at the intended destination. I restrained from kissing the runway upon climbing out of the plane.

[Otto55]

(11-08-2016 03:26 AM)TASP Wrote:  I restrained from kissing the runway upon climbing out of the plane.

LOL - didn't know that the guy in white was you.

Seriously, some warbirds in WWI operated at 145 km/h - easily reached by today's cars.