USB OPTO UART (RS232 but TTL levels)

This is an adapter for USB to TTL levels serial port
It also have optocouplers. Your computer should be safe even if you make wrong connections.

fig 1

fig 2

fig 3

Bill of material

Product numbers are from: www.elfa.se

M1

USB-modul USB, UB232R
elfa: 73-206-72
q: 1
price: 186 SEK

IC1, IC2

Optokopplare DIL-6, H11L1M
elfa: 75-204-08
q: 2
p: 12 SEK

C1, C2, C3, C4

Keramisk kondensator 33 nF

R1, R2

470 Ohm

D1, D2

"Zenerdiod 15V 2W"
ELFA:70-064-93
q: 1
price: 3 SEK

F1, F2

Säkring Polyfuse 0.2A 60R 60R010XPR
elfa: 33-238-70
q: 2
price: 6 SEK

J1

Molex Stiftlist, Vinklad 1x4P, 7395-04B / 2205-7048
elfa: 43-810-18
price: 16 SEK
q: 1

misc

Labbkort Fenolpapper FR2
elfa: 48-329-79
price: 27 kr
q: 1

Pres.-IC-sockel, DIL 6
elfa: 48-156-60
price: 5kr
q: 2

Elektroniklåda PC 100 x 50 x 25 mm, 1591ATRD
elfa: 50-236-01
price: 48 SEK
q: 1
fig 4

How to use

fig 5

linux:
picocom -l -b19200 /dev/ttyUSB0

Where 19200 is desired baudrate.
ttyUSB0 is the serial port. If you have more than one usb serial port you may need to use ttyUSB1...

Windows:
Hyperterminal or something

Disclaimer and copyright

Copyright Henrik Bjorkman 2012

This is a prototype, all the above are ideas subject change, no responsibilities taken.