DM42 with homemade printer

Discussion around the Swiss Micros DM42 calculator.
dk-
Posts: 16
Joined: Wed Sep 23, 2020 7:46 pm

DM42 with homemade printer

Post by dk- » Fri Sep 25, 2020 8:27 pm

Hi,

I got my DM42 the other day and I'm very pleased with it. Since I don't have a HP printer I cobbled together my own:
Image

I've had to use the printer modules default font for text since it was too slow to send the text. I'll have to do some translation to get the correct symbols, but other than that it seems to work.

Regards,
Daniel

Michael
Site Admin
Posts: 243
Joined: Wed Apr 05, 2017 11:31 pm

Re: DM42 with homemade printer

Post by Michael » Sat Sep 26, 2020 12:19 am

Very nice. Congrats!
I've been thinking of this too ...

User avatar
ijabbott
Posts: 191
Joined: Fri Dec 15, 2017 2:34 pm
Location: GB-MAN

Re: DM42 with homemade printer

Post by ijabbott » Sat Sep 26, 2020 12:27 pm

Michael wrote:
Sat Sep 26, 2020 12:19 am
Very nice. Congrats!
I've been thinking of this too ...
May 2021? :)

Maxdao
Posts: 4
Joined: Sat Sep 26, 2020 10:05 am

Re: DM42 with homemade printer

Post by Maxdao » Sat Sep 26, 2020 2:24 pm

Awesome !
Could you please post more details on how you did that, and more pictures ?

User avatar
chr yoko
Posts: 22
Joined: Tue May 05, 2020 11:23 pm
Location: France

Re: DM42 with homemade printer

Post by chr yoko » Sat Sep 26, 2020 8:02 pm

Fantastic job ! :shock:

Would you share the work ?

List of parts used into that built (printer model, IR led model, arduino type etc ...)

Software used to decode the Infrared data coming from the DM42/HPs and transcoding it to the printer via USB.

:ugeek:
DM41L SN01063 - DM42 SN05658

dk-
Posts: 16
Joined: Wed Sep 23, 2020 7:46 pm

Re: DM42 with homemade printer

Post by dk- » Sat Sep 26, 2020 8:37 pm

Hi all,

The project is not really in a sharing state, but please feel free to look at the code: https://github.com/dankar/redeye

Here's some quick documentation written on the fly:

The Arduino Uno reads input on pin 3. This is either the pure IR signal (32768Hz when transmitting), or just high when a carrier is detected and low when no carrier. To get this to the input pin I used a simple IR transistor and an opamp for amplification of the signal.

The code then does some error correction and processing of the IR data and then finally forwards the data to another arduino for printing. I had to use two arduinos since my code was too slow when both doing interrupts for the IR data and also handling the thermal printer. The data that is sent to the second arduino is either text, or bitmap data, based on what is being printed. I haven't uploaded code for the second arduino yet. I'm hoping to unify this to one device soon, and the code would depend mostly on what thermal printer you are using (I'm using one from Adafruit.)

I'll make sure to update here when I have a more "complete" solution.

Regards

toml_12953
Posts: 667
Joined: Wed May 03, 2017 7:46 pm
Location: Malone, NY USA

Re: DM42 with homemade printer

Post by toml_12953 » Sat Sep 26, 2020 9:42 pm

Wouldn't this be a good item for SwissMicros to sell? It would be a great addition to many of their calculators!
Tom L

If I buy someone a drink to congratulate them, is it a Mazel Tov cocktail?

DM10L SN: 059/100
DM41X SN: 00023 (Beta)
DM41X SN: 00506 (Shipping)
DM42 SN: 00025 (Beta)
DM42 SN: 00221 (Shipping)

c0rpse
Posts: 5
Joined: Tue Sep 22, 2020 4:04 am

Re: DM42 with homemade printer

Post by c0rpse » Sat Sep 26, 2020 9:54 pm

Do you think it would be possible to decode to a device that appears to the computer as a usb hid keyboard?
That way you could "print" to a text editor on your computer.

I'm sure the hardest part would be figuring out how to display the graphs.

dk-
Posts: 16
Joined: Wed Sep 23, 2020 7:46 pm

Re: DM42 with homemade printer

Post by dk- » Sat Sep 26, 2020 11:42 pm

c0rpse wrote:
Sat Sep 26, 2020 9:54 pm
Do you think it would be possible to decode to a device that appears to the computer as a usb hid keyboard?
That way you could "print" to a text editor on your computer.

I'm sure the hardest part would be figuring out how to display the graphs.
That should be fairly easy, but I don't think you'd gain much by doing that. You can already get the prints as an image or text directly on the calculator and transfer to your computer.

toml_12953
Posts: 667
Joined: Wed May 03, 2017 7:46 pm
Location: Malone, NY USA

Re: DM42 with homemade printer

Post by toml_12953 » Sun Sep 27, 2020 2:29 am

dk- wrote:
Sat Sep 26, 2020 11:42 pm
c0rpse wrote:
Sat Sep 26, 2020 9:54 pm
Do you think it would be possible to decode to a device that appears to the computer as a usb hid keyboard?
That way you could "print" to a text editor on your computer.

I'm sure the hardest part would be figuring out how to display the graphs.
That should be fairly easy, but I don't think you'd gain much by doing that. You can already get the prints as an image or text directly on the calculator and transfer to your computer.
But why have an intermediate step? I may not always have access to a computer. Besides, the nostalgia factor is huge!
Tom L

If I buy someone a drink to congratulate them, is it a Mazel Tov cocktail?

DM10L SN: 059/100
DM41X SN: 00023 (Beta)
DM41X SN: 00506 (Shipping)
DM42 SN: 00025 (Beta)
DM42 SN: 00221 (Shipping)

Post Reply