IR serial port interface circuit for PC
"Glenn Meader" <starnet!apple!bedford.progress.COM!glenn.meader>
Message-id: <9311101718.AA26445@progress.progress.COM>
Date: 10 Nov 1993 12:20:50 U
From: "Glenn Meader" <starnet!apple!bedford.progress.COM!glenn.meader>
Subject: IR serial port interface circuit for PC
To: "Zoomer list" <zoomer-list-1993@grot.starconn.com>
Status: OR
I'd like to build a similar device
>>>for a generic PC. Radio Shack has a cheap IR receiver that is well
>>>suited for this, and IR transmitters at 40KHz are quite easy to
>>>build.
>If you made a product that was SMALL and could plug into the parallel port
>of a laptop (serial port option) and could send/receive IR to a nearby
>printer (modem), and make it inexpensive, I think there would be a good
>market for this! I know I'd like to avoid all the plugging/unplugging that
>goes on when I take my laptop away from my desk.
The following is a letter I got from Tony something, a PDP11 hacker...
It is a PC IR interface for the HP 48SX, which I gues works with the HP 95LX.
It costs #30 uk. to build.
I enclose the letter. A circuit board ;layout will be posted in about
a week. It is send AND recieve, unlike the Jeteye.
>From ARD@siva.bris.ac.uk Tue Jan 26 11:06:21 1993
Date: Tue, 26 Jan 93 11:14 BST
From: "PDP11 Hacker ....." <ARD@siva.bris.ac.uk>
To: PHUDL@csv.warwick.ac.uk
Subject: RE: Digital Circuit Simulator
Status: OR
INSTRUCTONS FOR THE HP48SX IR DECODER
1) The circuit diagram is attacted to this message, as a printable
ASCII TTYpic. I should be printable on _any_ printer.
2) Construction and layout is not critical and any metohd should work.
I used Verowire self-fluxing wiring system. I also socketed all the IC's,
but that too is up to you!
3) De-coupling capacitors and power connections are not shown on the circuit
diagram. Place a 0.1uF ceramic capacitor across the power connections on each
IC. Also place a 10uF tantalum capacitor across the power connections close
to the IR transmitter.
4) The IR LED and IR phototransistor should be mounted on the front panel of
the unit. The LED goes on the Left, looking at it from outside. They must line
up with the ones on you HP48 for transmission to occur at all. The range of the
unit is about 2".
5) The IR LED and phototransistor are critical. I used ones available from
MAPLIN (see my earlier messages for the address), but the equivalents are:
Phototransistor Maplin YY66W (Infra Red Sensor) = TIL78
LED Maplin YH70M (Infre-Red Emitter) = TIL38
6) The RS232 port links to the PC, not to the HP48 of course.
7) The circuit as given requires a +5V supply only. The MAX232 device (which
is expensive and hard to obtain) can be replaced by a 1488 (transmitter)
and 1489 (receiver) devices but then +/-12V are required for the 1488
8) Each section of multiple ic's is numbered. 'xx means 74lsxx. A total
list of ic's required is:
MAX232, 2*74ls393, 7425 (or 74ls25 if you can get one!), 74ls74, 74ls08, 74ls14
74ls04.
9) A list of symbols used is: (as some are non-standard to get them into
printable ascii)
-\/\/-- resistor
!
\
/
\ resistor
/
!
!!
--!!-- capacitor
!!
!--!
+! !+
-!! !!- Quartz Crystal
+! !+
!--!
!/
! NPN transistor
!\!
-
\\
>>
! /
!/
!\ IR phototransistor
! \!
-
! >>
V//
--- IR LED
!
!\
-! >o- NOT gate
!/
-!\
! )- AND gate
-!/
-)
)
-)--\
) >o-- NOR gate
-)--/
)
-)
Good Luck!
I am on ARD@UK.AC.BRIS.SIVA (JANET) = internet ARD@siva.bris.ac.uk
+5
----
! -----------------------------
! ! !
/ ! ----+ o '74
\ 10k '04 ! '04 '04 '08 /// ! ---------
\\ / !\ !\ ! !\ !\ +-!D S !
>> !--------! >o---+--! >o-+-! >o--! >o--!\ ! Q!
! / !/ ! !/ !/ !/ ! )-+ ! !o------+
!/ IR 74ls14 ----------------------!/ ! +- !> R ! !
!\ P/transistor ! ! --------- !
!_\! ! ! o +5 !
! ---------------------------- ! ! ---- !
! ! ! ! ! !
--- ! ! ----- !
/// ! ! !
'393 ! '14 ! !
---------- !\ ! !
! R ! +- ! >o-+ '25 ! !
! A!-+ !/ +-----) ! !
! ! ) +---+ !
! B!---------------)--\ !\ ! !
+---!> ! ) >o--! >o--+ !
! ! C!---------------)--/ !/ !
! ! ! ) '14 !
! ! D!---------------) !
! --------- !
+-----------------------------------------------------+ !
'393 '393 ! !
2.45MHz !----! !----! ! !
'04 !--! '04 '04 ! A! ! A! ! !
!\ +! !+ !\ !\ ! B! ! B!--+ !
----! >o-+-!! !!--+---! >o-----!--! >o---!> C! +-!> C! ! !
! !/ ! +! !+ ! !/ ! !/ !R D!-+ !R D! ! !
! ! !--! ! ! !----! !----! ! !
! 1k ! ! 1k ! ! ! ! !
-/\/\----+ 2n2 --/\/\-------! --- --- ! !
! ! ! ! /// /// ! !
------------! !-----------------+ ! !
! ! ! !
+5 ! !
---- !! !! 4*22u ! !
! +-!!-+ +-!!-+ ! !
! ! !! ! ! !! ! ! !
! ! ! ! ! ! !
! ------------------- ! !
! ! C1 C2 ! +---------------------------------)---+
+----!Vcc ! ! !
--- ! ! ! ! +5
---+ ! ! ! ! ----
+----!+10v ! ! ! ! >>
! ! ! +-----------------------------+ V //
PC ! ! ! ! '393 ---
RS232 ! ! ! ! !----! ! IR
>-----!TxO1 TxI1!--+ ! ! A! +-/\/\---+ LED
Tx ! ! ! ! B! 2N3904 ! 56R
!TxO2 TxI2! +---!> C! !/
! ! +-------!R D!----/\/\----!
>-----!RxI1 RxO1!--+ !----! 1k2 !\!
Rx ! ! - !
!RxI2 RxO2! !
! ! ---
>--+ ! -10V Gnd ! ///
Sg ! -------------------
! ! !! !
! +--!!--+
! !! !
--- + !
/// !
---
///
--
*----------*-------------------------------------------------------------*
| Sam Jam|"Never underestimate the importance of a cheap laugh"- |
| Liddicott| phudl@csv.warwick.ac.uk Plucky Duck TTA |
*------------------------------------------------------------------------*