#garfield Logs

Jun 26 2021

12:42 AM rue_shop3: hahaha
12:49 AM rue_shop3: I
12:49 AM rue_shop3: *sigh*
12:49 AM rue_shop3: dont have a resistor the right size to regulate the current on the new motor
01:16 AM rue_mohr: ok I found some to common up
01:16 AM rue_mohr: thank gosh for my brute-force solvers
02:30 AM rue_shop3: ok all sorts of isues
02:30 AM rue_shop3: the drivers seem to saturate about 3A
02:31 AM rue_shop3: so it threw off the ballast calculatons
03:47 AM polprog: aandrew: looks good :D
10:25 AM Tom_L: ok i picked up one of those step drills. maybe that will work
03:25 PM rue_shop3: just in time to hide from the heat?
03:27 PM rue_shop3: 560 ohm resistors
03:32 PM rue_mohr: ordered
03:32 PM rue_mohr: bit of $6 for 1000
03:43 PM rue_mohr: the vga to hdmi converter arrived
03:43 PM rue_mohr: now I can do vga->hdmi->capture and record me oscilloscope screen
04:06 PM aandrew: rue_mohr: the photodiode is to measure the dye absorbence (or rather what it lets through) of a small readout well on a polycarbonate disc as it spins around at around 3000rpm
04:06 PM aandrew: polprog: yeah I found some amazing resources on analog.com and played around
04:07 PM aandrew: it still amazes me that the photodiode's 140pF is NOT the issue, it was the feedback capacitor which was rolling things off waaaaaaaay too soon
04:07 PM aandrew: also, I thought a transimpedance amplifier was a specific "design" of op-amp, not a design of an op-amp *circuit*
04:08 PM aandrew: however TIAs usually *use* special op-amps where the special bits relate to low noise and input offset
05:36 PM Tom_L: no luck today
05:52 PM Tom_L: you would think by swinging the column it would eventually become parallel to Y
05:53 PM rue_mohr: ?
05:53 PM Tom_L: didn't appear to affect it acording to the dial indicator
05:53 PM Tom_L: i made damn sure it was turned too by pushing the head with the X axis
05:54 PM Tom_L: then tightening things up
05:54 PM Tom_L: should act like 2 hands on a clock. eventually they will be parallel
05:55 PM rue_mohr: did it get closer?
05:55 PM Tom_L: didn't seem to
06:25 PM Tom_L: i should do a cad model of it to see how bit the holes need to be to move enough
06:50 PM Tom_L: i'll put a dial on the table later but i'm not gonna tear that setup off just to do that
08:50 PM Tom_L: rue_mohr, tell me you accomplished something today...
08:51 PM Tom_L: i'm a bit pissed and dissappointed at the same time
09:13 PM Tom_L: it absolutely doesn't make sense
09:50 PM Tom_L: ok rue_mohr this may not make sense to you but i drew a diagram of the error and possible correction for the error: http://tom-itx.no-ip.biz:81/~webpage/rue/tramming/XY_error1.jpg
09:51 PM Tom_L: a layout of the mill and bolt pattern for the column
09:51 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/rue/tramming/XY_error2.jpg
09:51 PM Tom_L: the left line is the distance from the column to the vise i was measuring the error
09:52 PM Tom_L: the right line is the end of the vise measurment
09:52 PM Tom_L: the green line is the base line, white represents the error and yellow the ammount of correction i should have
09:52 PM Tom_L: based on the size of holes i drilled
09:53 PM Tom_L: there should be ample adjustment for that minimal error
09:53 PM Tom_L: it's just not showing up and i dunno what i'm not doing right
09:54 PM Tom_L: it should be an accurate representation of the distances and error
10:55 PM Tom_L: :/
10:55 PM Tom_L: ok one last time i went and checked but i used 2 different vise edges and got it within .001" over 6" which i can live with
10:56 PM Tom_L: aparently the vise edge i was using was crooked