Nuts & Volts - May 2007

>>>READER-TO-READER QUESTIONS AND ANSWERS

one in my barn with a four line x 40 or 80 character monochrome LCD display and a membrane type QWERTY keyboard. I work in Rochester and would be willing to give it to you if you contact me at: 300 Meridian Centre Blvd., Suite 100, Rochester, NY 14618. I can also provide you with the dates and locations of upcoming hamfests in your area.

3) Celery LLC (1-866-692-3537) may have just the ticket for your email using fax. Celery looks like ordinary fax machine, but it does something that most fax machines don’t — it sends and receives email. To send an email, you handwrite a note and feed it into the fax machine. The recipient then receives your note as an attachment. As for incoming emails, they come through like ordinary faxes. One year of Celery’s black & white service retails for $219 with the device, or $259 for the device and one year of color service. I haven't contacted them but they may have a plan that would work with your existing fax machine at a lower cost.

Other possible options are the "Mailbug" from Landel that uses an integrated keyboard and monochrome LSC display which connects directly to the phone line. Main: (408) 360-0480; Customer Support: (408) 360-0490; Fax: (408) 360-0499.

Finally, Presto is a new online printing service that presents an innovative solution: The service allows you to send email, including photo attach-

ments, to a Presto email address. There, the service converts the email and any attached photos into cus-tomizable layouts ready to print out on a $150 HP A10 Printing Mailbox (currently the only Presto-enabled device). The printer receives and prints information automatically. Because the Printing Mailbox connects to the phone line, it doesn't require an Internet connection or a computer to automatically check for and print content — which it does at intervals that you schedule during setup. The Presto Service costs $10 per month, or $100 annually. Phone: 800-919-3199.

John Jones Rochester, NY

#2 1) In the old days, you programmed your processor from the front panel. Switches and paper tape were the way things were done. For a while, many microcontroller programmers were done using identical microcontrollers to program the other one. It can be done; a boot strap approach would be the best. Start with maybe something like the 1802 based ELF that was featured recently in Nuts & Volts. Build a small controller board from that to load your microcontroller code into. Then, using a serial or parallel programmable part (PIC, AVR, Freescale, etc.), the elf could do the programming. Once the microcontrollers can be programmed, build an easier programmer for them, maybe including an assembler/debugger.

2) I think I have an old Televideo terminal in unknown state in my storage room. I used the heck out of it on CP/M machines, 15 years ago. Recently (last couple years or so), I remember seeing RS-232 based terminals using a PIC chip and an LCD display. The TI Silent 700 was a thermal printer terminal, sort of like an old teletype; no video display, that sometimes had an acoustic coupler on it. I think its max speed was 300 baud, but could have been faster. The ones I used were always connected to the modem.

3) Most PCs can configure their modem to fax mode, and some software can be used to have the fax modem work as a printer device. There are fax services that will send a received fax as an email attachment. Yes, it is theoretically possible to use the fax as a way to send and receive email, and not too cumbersome.

Tom Brusehaver Bloomington, MN

[#2072 - February 2007]

I'm looking for a circuit diagram that will let me know the status of a fuse in a 12 VDC circuit and 120 VAC circuit. It must light an LED to show that the fuse has blown. It would be used to monitor automotive fuses and the fuses for an amateur radio station.