Working with my good friend Daniel McLaren on a cool interactive
art project, I designed a board around the ATtiny841,
which is a nifty new entry to the AVR portfolio. Unfortunately when intial power up of the
board was successful, I found I was totally unable to write code to the device with
avrdude as I normally would; the chip is unsupported in even the
latest version. I found a helpful post
on AVRFreaks with a code listing for avrdude.conf that was purported to work, but I found it
produced verfication errors (and a non-working chip) every time.
After much mucking around and recreating the part in avrdude a dozen times, I got it to work.
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Prompted by user Skimask over on the eevblog forums, I undertook some performance testing of an AD9850 module, readily available from eBay (search 'AD9850 DDS') for under $10 shipped. These are advertised as 0-40MHz devices, and appear to include the datasheet-recommended 5-pole output filter and a 125MHz canned oscillator. Measured distortion and spurious performance is excellent, especially for the bargain-basement price.
Skimask was curious about the performance at audio frequencies, so I undertook some measurements at 1KHz and 5V.
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I've ordered myself an EA3GCY ILER-20 kit, and being a single-band QRP hand-tuned radio, I want a convenient counter. I'm going to be using this in the field on battery power, so it's got to sip the juice and be small (tiny!) and light. The design should be suitable for any small HF rig (and maybe 6 metres) with an easily accessible point to measure the VFO.
I put together a design and just ordered PCBs.
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I did a short YouTube video on some Pomona 5519a test leads I picked up to replace the really cheap ones I was using. See the video:
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Having ordered a used mobile radio from eBay, I felt that I needed a dummy load for tuning and testing. While I was at it I figured I'd add a peak detector to get a reasonably accurate power measurement at the same time.
I pulled two bits of heatsink that came from an old PC power supply, an AC filter capacitor and a couple of signal diodes from the junk bin.
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A while back I spent some time building a stratum 1 NTP time server based on a Motorola Oncore UT+ GPS receiver and an old (decommissioned and free) PC Engines WRAP.1E-1 board. I was inspired by N8UR's (John Ackermann) essay on using the Soekris net4501 single-board computers as high-accuracy time servers, which I don't have - but I thought I'd do what I could with the WRAP. I rigged up a level converter and hooked the Oncore up to the WRAP's serial port, installed FreeBSD and got it up and running keeping good time.
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