Dave Brown playing for a while:)
Project intended to progress sometime in the future
|Reconfigurable sailing proa||mostly inactive, built small bits||Rob Denny at http://www.harryproa.com has some interesting things to say about Proas and how they could be the basis for a cheap, high performance, spacious sailing cruising boat. Perhaps the ideal cruising boat :). I want to explore the sailing characteristics in a model.|
|LED lights and lenses for my bike||active|| http://pilom.com/BicycleElectronics/DynamoCircuits.htm explains the matching of LEDs to bike generators. I plan to have several strings of LEDs with different beam angles and aiming points - and the appropriate string of LEDs turned on for the current bike speed.
|Visible surge arrestor||project||I want to know when power surges happen, and if possible stop them cheaply and quickly. Project:Surge Arrestor|
|Low viscosity blood||thoughts||I have some more reading to do; but am intrigued by http://customers.hbci.com/~wenonah/new/mcdaniel.htm and http://en.wikipedia.org/wiki/Integrated_Pulmonary_Index|
|Quiet boxed PCs||project||I want to run more than one PC, and the droning gets to me :( Project: Quiet Boxed PCs|
|Power efficient raid||idea|| Data needs to be written to multiple drives; so a single head-crash does not wipe it out. However, it could be staged to disks sequentially, remaining in memory until it has been written on the 2nd (or n'th) drive. The drives could be spun up more rarely, to simply update the file-store.
Perhaps it can be done using two or more file systems and unionfs; with the data eventually residing on a spinning disk, but initially being saved on ssd. The spinning disk using btrfs to make a sequence of stable snapshots from changes preserved on the ssd. Maybe btrfs offers this sort of thing directly?
|Make solar cell?||idea||Link http://www.freewebs.com/acselectronics/TiO2solar.html|
|Safe by design nuclear||meme||2 hour promo|
|bike trailer||sketches on envelopes|| to carry standard building 2.44 x 1.22 M sheets, 2up kayak, etc. Considering
|tricycle||just a thought||Means of getting around...|
|hack caliphers||seen in sparkfun comments|| Member #333257
If you measure current, you will see that the power off state draws 90% of the current of the power on state. For some reason, all electronic calipers seem to be this way- power off is actually display (only) off. THIS is why the batteries go bad quickly.
I just open the caliper case, cut the battery trace (which one doesn’t matter), drill two holes to allow the fine (wire wrap) wire to come out the top to a micro-miniature slide switch glued to the top. I always turn the switch off, rather than press some caliper “off” button, and find that a button cell lasts for many years. I would attach a picture if Sparkfun allowed, but it doesn’t. Caliper thickness is unchanged, and the outline is very nearly unchanged.
|temperature controller||plan|| to control cooker for soldering SMD.
|Infer unit-testcases from a functions code||thought|| Summary: Use the parse tree for a function as input to heuristically apply symbolic logic that aims to build information about the values of parameters required to invoke particular functionality with-in the function.
So for example given a function "uint32_t f(uint32_t i, std::string s)", it starts with a range of possible inputs of (i in [0,2^32-1] x (s.size() in [0,2^32]) x [set-of-possible-values-of-actual-length]) , which is nearly infinite. Then from the parse tree, derive the possible effects of the code, and the sub-ranges of the inputs that are required to have these effects.
|prime number generator||thought|| Invert the sieve of Aristophanes, so the data structure holds primes and the next multiple of each prime. Keep the data-structure sorted by the next multiple. When a gap occurs between the current nearest multiple and the next nearest the gap contains prime number(s).
The algorithm requires sorting subsequent multiples into place. If N is the number of discovered primes N, and the size of the primes is S; then the memory used is O(N*S) and the CPU time used is O(S*N*N).
|factorisation||thought||By trial division using list of known primes; is exceedingly slow for large numbers; the number of potential factors is O(sqrt(N)) - if N is more than 100 bits that is a big number. However, can knowledge of the factors be used to restrict the search space usefully? What are the constraints on the factors imposed by PGP for example|
|mirrored coils||reinventing the wheel; already exists as a Common mode choke|| wind two coils on the same core, one left hand the other right hand and link them together. I think they should act as a filter of some sort, because the emf generated by the first travels faster than the electrons and reinforces the current in the other coil, smoothing out the edges of each pulse. The filter frequency being related to the speed of light and electrons in copper and the coil winding length. Maybe there would be less energy lost in the filter?
I need to learn some maths so I can understand the wiki explanation.
|Lowered Desk||complete||Comfort requires a good desk:). Project:Lowered Desk|
GDT 420v surge arrestor for 240v (if my calculations are right)
wire to board screw connectors 300V 20A
Electrolytic Cap 50v, 2200uF, 8k hours lifetime, 3A ripple current, 23mOhm inductance, ?ESR.