AN AMERICAN company, Mindware, has produced a blue-ink-on-plain-paper printer for the ZX-81. Having 16 characters per line, it cannot produce the full screen picture like the Sinclair printer but the user can set various modes to give the display he wants by POKEing a system variable 16417 with the mode required.
After that the printer will react like the Sinclair printer to COPY, LLIST and LPRINT. The port used is the same as the Sinclair printer and an EPROM in the printer controls its operation without taking up any memory space.
Mode 1 is the screen split in half, the left-hand side being printed before the right-hand side; Mode 2 will be used for extra character sets in the printer, Mode 3 is for a 16-character line LIST and Mode 0 is used for LLIST.
The paper used is the same type as for till rolls and the ink cartridges are easily available. All graphics are printed. The printer costs £65. Mindware is at Wayland, MA 01778 U.S.A.
ZXED d'Ktronics Basic editor is now available on EPROM for those with the graphics board from the same firm. Instead of a long wait for the cassette to load, it is available instantly by typing in RAND USR 16025.
It will then provide facilities such as a full renumber of GO TOs, as well as GO SUBs and line numbers, Find, Insert, Delete, Move, Copy and Keep Basic lines within a program. Keep and Insert store program lines above RAMTOP to be Inserted into another program. Alter allows you to search the program for a string of characters and replace them. A help instruction is also included, giving instructions on using ZXED.
The 4K EPROM is in the RAM socket provided on the graphics board and does not affect the use of the other EPROM. The cost of the EPROM is £9.95 from d'Ktronics, Great Yarmouth, Norfolk. A keyboard is also available for the Spectrum complete with numeric pad for £30, plus £15 for the case, but you have to add £1.50 for postage and packing.
CHESHIRE Micro Design has produced a temperature sensor for the ZX-81. The device, called the ZR3, plugs into the EAR and power sockets of a ZX-81 and can measure temperatures from -5 to +100 degrees centigrade.
The measurement time is one second and a USR machine code routine is provided as a listing or on cassette. The unit is hermetically sealed and the probe can be up to 35 metres long; two metres is provided.
The probe returns a number between 500 and 2000. Accuracy is claimed to be to one degree centigrade.
The ZR3 can be obtained from Cheshire Micro Design, Stoke-on-Trent. It costs £17.50 including post and VAT for the U.K. Foreign orders should add postage for 240 grammes.
A GRAPHICS plotter sheet for the ZX-81 is available from Ad-Lib for formatting your screen display. It consists of a plastic-coated paper sheet 8 by 11½in., with the screen PRINT squares on one side and the PLOT squares on the other.
On the PRINT side there is also a list of the graphics symbols. The sheets are supplied with an overhead projection pen which must be used. They can be reused by erasing the drawing with a damp cloth.
The cost of five sheets and one pen is £2.50 and a pack of coloured pens for formatting on the Spectrum is available at £4.75 from Ad-Lib, Hitchin, Herts.
TAURUS Computer Design has produced two EPROMs on a board for fitting inside the ZX-81. The first contains a monitor plus an added disassembler in 4K. The second contains an assembler for rapid translation of machine code programs into bytes on which the Z80A can run.
Together they make a very powerful machine code facility which is available at switch-on by using a USR routine. The board fits underneath the keyboard and resides in the memory from 8K-16K.
There is also a word processing EPROM (4K) which will provide up to five character sets, including lower-case characters. The monitor, disassembler, assembler and character set are also available on cassette.
The board and monitor disassembler costs £30, the character set EPROM £10, and the assembler EPROM £12. Cassette versions - monitor £8.75, disassembler £6.50, character set £6.50, assembler £6.50; a user manual is provided with each. Taurus is at 47 High Street, Baldock, Herts.
GORDON Electronics has produced a keyboard in a case which requires no soldering to attach it to the ZX-81. The pins provided on the end of the ribbon cable push into the keyboard sockets on the ZX-81 printed circuit board.
The cost of the keyboard is £25.50 and in its case it is £37.50, including VAT and postage.
Gordon Electronics, Braintree, Essex.
MEMOTECH has added three new black boxes to its range. A hi-res board - 192 x 256 pixels - can have its memory page anywhere in RAM and it can also have more than one of the 6.5K pages stored in memory for rapid graphics. The hi-res can be used with any of the company's RAM packs, including the new 32K.
The 32K RAM pack can have an existing 16K RAM pack - not only from Memotech - added to give 48K of usable memory.
The black box is a Centronics-parallel port plus driving software to run a printer. The 32K RAM costs £49.95, Hi-res £61.80, Centronics port £41.90.
Memotech Ltd, Oxford.
MANSFIELD Computers and Electronics now supplies printer paper at £10.95 for six rolls, as well as software and books for the ZX user. Mansfield Computers and Electronics is at Mansfield, Notts.