2017-11-07

Very few things didn't work when I moved to Linux. Now there is one less...

There are things that couldn't work. There were things that I didn't need. Then there were applications or hardware that just didn't work, try as I might.

I still haven't got round to writing a driver module for my Microtek slide scanner. I kept a Windwoes 98 PC alive just to use it to scan slides.

Then there was the QX3 Intel microscope. This had nothing for Linux. It would only grudgingly work in Windows XP. When reading glasses and magnifying glass did not work, I would reach for the QX3. Only to find that I had put it on the top-most shelf. Out of reach...

Now I have a fully working QX3. With pictures of transistors and high precision voltage regulators. That I could not read satisfactorily with reading glasses and magnifier.

It is all thanks to the Linux community. Persistence pays off.

This only 10 times magnification. Makes them easy to identify, even when the paint is obscure.

The link? Sure! Here it is :-

Whoopee!

This is the latest thing to make me realise that moving to Linux was a good idea! All those old USB and Serial/SCSI scanners? Try 'simplescan' under Linux...

In fact if your are like me with a Windows 9x PC just scanning, try booting on a live Ubuntu/lubuntu CD or stick. Then try running 'Simple Scan'.



2017-10-07

My serial port PIC programmer doesn't work!

It seems that the 'issue' that plagued us when NT4 came out is still with us. At least for 'newbies' or others like me who was given a serial/RS232 PIC programmer. 

The other 'issue' is that most new hardware, laptops and desktops, don't have serial ports. So the 'user' is forced to use a USB to RS232 adapter. This 'adapter' does not have the correct RS232 voltages on its pins... So any circuit connected to it does not get the correct voltage [higher than 5 Volts]. For example: Several packet modems would not function with the later models [9 pin] interfaces. These modems were [correctly] designed to connect to a 'real' RS232 interface. Which goes negative with respect to the ground [0V] pin. The interface circuit required the pins to go below -3 Volts for correct switching. This is to improve the noise immunity of the circuit.

With the PIC programmers, it is a case of cheap [sorry cost effective] design. So that the programming voltage of 12V plus a bit was derived from a charge pump, which was fed from 5 Volts [either RS232 or USB]. This did not work as the designer[?] thought you would connect it to an RS232 port with +/- 15 Volts on its pins.

A lot of the software was developed in the 90's. When Windows 98se was 'the thing' to have. So the developer could access the hardware ports without asking the 'boss'. When XP came along and replaced Windows NT and 98, suddenly the software wasn't allowed to access the hardware. And stopped working.

So two 'issues' affect any hardware interfacing software from last century. No access to ports and the original RS232 specification.

So when you try Linux with your 'veteran' PIC programmer, the situation get worse. You are NOT the 'superuser', so you cannot DO THAT! [It will be reported to Santa before Christmas] Any hardware accessing MUST be done by the superuser. So get used to running the software as SU or SUDO.

Then the software has to be run in "compatibility mode"  - hmm, Windows 7-10 has this but I don't believe it allows access to the hardware. OK, try a virtual machine? No dice there either. Restrictions usually apply...

How about finding an old laptop with serial ports? Or buying a recent DELL laptop with serial and parallel ports? If you can find one it is probably running XP. So the software won't be allowed to access the ports. But you can probably boot the laptop on another disk or CD. This disk can be made from your current PC/laptop to boot FreeDOS or even Windows 98's DOS. In the case of the DELL laptop, you will probably be able to boot a stick/thumb drive.

How do you get the right programming voltage?

Some of the PIC programmers have an external power connector. This allows you to plug in a "wall wart" power source. Usually a 12 Volt power supply for an external hard disk will do the job.

There is more to come ...





2017-06-26

Some things will never work!

A circuit that I found the other day...















Having shorted out the crystal, I doubt the circuit will oscillate. But you never know for sure. Maybe at VHF?

Another circuit I found recently was a sound card interface for a transceiver. It uses an opto-coupler to isolate the PC's serial port from the radio...

Apart from the fact that in general there should be no need for isolation, the person who put this circuit together, forgot the RS232 specification...










So put a diode across pins 1 and 2 in the opposite polarity. Just to protect the opto-coupler.


Ham-Comp

Our recent Ham-Comp session, had more people visiting the club. More interested parties and some lessons learned. 

WSPR for the Raspberry Pi


The GitHub links:-

https://github.com/JamesP6000/WsprryPi

https://github.com/threeme3/WsprryPi