Friday, November 21, 2008
Verkkokauppa.com:s 199 euro offer for a 2-year-old refurbished Thinkpad T40p proved irresistible, and I was lucky to pick one up after queuing outside for 35 minutes. The place opens at 9, I arrived around 8:55, but some people had apparently been outside the doors waiting already at 7:30! The 19 euro mobile phones sold out [...]
I used this Sallen-Key design to build an 8-channel 4th order low-pass anti-alias filter for a 16-bit 200 kS/s +/- 10 V AD-Converter. I calculated the components for the 60 kHz low-pass Butterworth design with this on-line calculator. Previously I've used the MAX274, but that component is limited to +/- 5 V signals. Here I [...]
This is the E-stop circuit I am going to use when upgrading the cnc-mill to servo control. The idea is to use a wire-OR circuit (series connection of NC switches) for things that cause an E-stop followed by a wire-AND circuit (parallel connection of relays) for things I want to happen at E-stop. The E-stop [...]
Saturday, November 17, 2007
By popular demand, some notes on how I've placed the antenna of my Spektrum DX6 transmitter inside the case. I've been using the radio like this ever since I got it and provided that you hold up the radio more or less vertically and not hide behind large metal constructions or things like that the [...]
Spektrum recently introduced an updated version of the DX6: the DX6i. Horizon Hobby also has an article on the new radio. This one uses 'DSM2' technology which is described as giving 'full range'. Not sure what that means, but range should be better than with the first generation of 2.4 GHz radios, which at times [...]
Friday, September 21, 2007
I reluctantly sold a 20" 1600x1200 Viewsonic with the desktop machine when I switched to my current T60 laptop (14" 1400x1050) about a year ago. The screen is not the strongest point of the T60, and that feeling has just been reinforced by looking at some 22" Samsungs at work. Now prices have plummeted again [...]
There was something strange going on when I measured the transformer last time, and since that I've gotten a few pointers from visitors to the blog and the CAD_CAM_EDM_DRO list. I now did a test without the inrush current-limiter, and it does make a difference. It is rated for 8 A continuous current, but apparently [...]
I've put together a simple unregulated power-supply for use with the DC servos that are going on the cnc-mill in the near future. The design is as simple as it gets: 230 VAC input, fuse, 2-pole switch, inrush-current limiter, 1.8 kVA toroidal transformer with twin 30 V secondaries in series, diode bridge, and finally four [...]
A friend at work showed me this combination of an N95 and a folding bluetooth keyboard! With 3G/WiFi/GPRS connectivity you can read email and surf the net almost from anywhere. The only thing holding me back is the 690 euro price tag...
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Thursday, November 9, 2006
Rob Guyatt, designer and builder of RMG winches has answered to the challenge from the super-quick arm-winch camp by sourcing a new motor for the RMG280D (the most popular model for an IOM). The motor is about 15% faster than the previous model, while torque is about the same or slightly less. Couple the new [...]
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