bad_ideas_in_action

maryland mountain hard money/black line

bad_ideas_in_action — Mon, 16 Oct 2023 04:59:42 GMT

really chunky. There's a big exposed rock 23 seconds into this that I haaaaaate, but it doesn't look so bad in the shade in this video

IONX0004

bad_ideas_in_action — Mon, 16 Oct 2023 04:46:26 GMT

maryland mountain black line fast chunky and scary

antelope_rocky_turn

bad_ideas_in_action — Thu, 28 Sep 2023 03:50:22 GMT

A difficult rocky climbing turn that we only sometimes manage to climb without touching the ground

upper_antelope_descent

bad_ideas_in_action — Thu, 28 Sep 2023 03:44:02 GMT

nice fast rocky descent

trestle_with_s

bad_ideas_in_action — Mon, 18 Sep 2023 04:04:14 GMT

part of a descent with a coworker

Old aviation gauges can be spicy

bad_ideas_in_action — Tue, 05 Sep 2023 00:42:28 GMT

We were given some old aircraft flap indicator gauges and a friend suggested, when I posted a pic on mastodon, that I might want to run them past a Geiger counter.

Closed loop fan speed controller

bad_ideas_in_action — Fri, 03 Mar 2023 06:10:42 GMT

Arduino fan speed controller using magnetic rotary encoder for rpm sensing. Controller takes text rpm command and varies pwm output to match the setpoint.

Unmolding_lathe_carriage_clamp

bad_ideas_in_action — Fri, 29 Apr 2022 04:21:51 GMT

Breaking the finished aluminum casting out of the plaster of paris mold

alumium_casting_day

bad_ideas_in_action — Fri, 29 Apr 2022 03:44:39 GMT

This is the casting section of my 3d print-invest-burnout-cast process. I'm casting with aluminum from broken up engine blocks, using greensand moldmaking strategies (pouring cup, sprue, bottom-fill mold, expansion risers) with some investment/burnout strategies (copious venting to allow the melted PLA to pour out during burnout.) There are two castings here, one being a carriage way stop for my lathe, that was formed with an adjustable investment enclosure so I can minimize the investment used, the other being an intake manifold for a Datsun engine, that was formed by shell investment, where I painted the investment on. The poured investment worked very well. The shell casting did not.

Speeduino sim hardware demo, with less audio glitches than my last attempt

bad_ideas_in_action — Sun, 13 Mar 2022 04:47:11 GMT

Demo of sim hardware to provide correct inputs to a Speeduino ECU and measurement of the Speeduino PWM output to the fuel injectors. This includes a simple potentiometer simulating the throttle plate position, a potentiometer (poorly) simulating the thermistor used for measuring intake air temperature, and another arduino bitbanging a 35:1 crank RPM and position indicator, and showing the input signal and resulting output signals on my scope.
I previously uploaded a video with similar content but it had weird glitches (maybe from recording, maybe from re-encoding when I spliced two segments together.)

speeduino ECU simulation

bad_ideas_in_action — Sat, 12 Mar 2022 21:26:13 GMT

Simulating inputs from a 35:1 missing tooth crank wheel, throttle position indicator, and coolant temperature for a Speeduino board and measuring the resulting pulse width/duty cycle for a two fuel injector output.

repairing worn out encoder knob on HP/Agilent E36xx power supplies: speedrun

bad_ideas_in_action — Thu, 29 Apr 2021 13:04:52 GMT

Repairing the worn out knob on a 30 year old HP E3648 power supply. This procedure and part works for any E36xx series. The mechanical encoder costs under $2USD from digikey and only takes a few minutes to replace. The power supply case design is excellent and easy to work on.

hot glass calligraphy

bad_ideas_in_action — Wed, 03 Mar 2021 06:47:38 GMT

First attempt to draw kanji using glass stringer on a glass bead, using my nortel oxypropane torch. I make a bead, flatten it with a carbon paddle to provide a flat surface, draw out glass stringer, reduce the flame size appropriate with the stringer, and draw the kanji on the bead surface. Then I melt it in to form a more or less flat surface with the drawing on it. The stringer I'm using is still too broad so it spreads out too much; I'll make some roughly 0.5mm stringer and try again later. But it was still relatively successful.

Arduino drawing on scope xy mode: why filtered pwm is rubbish

bad_ideas_in_action — Sun, 14 Feb 2021 22:46:25 GMT

I'm using an rc filter on pwm to make a dac and draw pics. This is written in assembly for speed, with no divider for the pwm frequency. At 0 and 100% duty cycle the rectangle is excellent but as I draw smaller rectangles by moving the duty cycle of the four points closer to 50%, the lines turn into disasters coz the rc ripple dominates. So I need a better dac if I want scope calligraphy.

Solenoid timer

bad_ideas_in_action — Sat, 19 Dec 2020 05:37:20 GMT

This was commissioned by a friend who is riveting the skins on an aircraft. He needs precise dimples and rivet setting. I built a timer using an atmega328's timer0 driving a lowside fet to sink 12v from the coil, with a button trigger and a turn/push user interface for the LCD. This implementation times 10-2200mS to sub microsecond repeatability. The air valve is rated to 100psi/6bar but leaks slightly at 3/4 that so I need to find a better one.