Ukusebenzisana
UBUCIKO
UBUHLE NEMPILO
UBUCIKO BEZANDLA
AMASIKO NOMLANDO
EZOKUZIJABULISA
IMVELO
UKUDLA NEZIPHUZO
REVERSE ENGINEERING
IZAYENSI
EZEMIDLALO
UBUCHWEPHESHE
IZINTO EZIGQOKWAYO
Digital Tachometer: Hand-Held Contact Type That Holds Its Reading (Sugiyama, Shimpo, US 4,000,465, 1976)
A hand-held digital tachometer. You press the contact head on its shaft against the end of a turning shaft and push the thumb button; a slotted disk inside chops a light beam into pulses, and the pulses counted in a fixed time, set by a quartz clock, appear in the window as the speed. A latch holds the reading after you take the tachometer away, so you can read it even where you could not see the window while measuring.
Result: a contact tachometer that shows revolutions per unit time and keeps the last reading.
Source: Y. Sugiyama (Shimpo Kogyo), US 4,000,465 (1976). Unknown: the number of holes, the clock, the gate time and the circuit details. Picture: the patent drawing.
Osezingeni eliphezulu
Unknown
Imiyalelo
1
1
Make the housing and measuring shaft
Make the housing and measuring shaft
Make a cylindrical housing to hold in one hand, with a window in its side for the reading and a push button for the power switch where the thumb falls. Run a measuring shaft out of the front end in bearings and fit a contact head on its tip to press against the shaft being measured. Not given: materials, sizes. Ours: aluminium tube, a ball bearing.
Izinto zokwakha zalesi sinyathelo:
Ipayipi le-aluminium1 housing
Insimbi engaziwa1 measuring shaft
I-Bearing Yamabhola1 ucezu
Okokwakha okungaziwa1 contact headAmathuluzi adingekayo:
Umshini Wokuphendula Insimbi
Ibhola lesandla
Izilinganiso ezingaziwa2
2
Make the pulse generator
Make the pulse generator
Fix a disk on the measuring shaft with a ring of small holes evenly spaced near its edge. Put a light source on one side of the disk and a photodetector on the other: each hole passing makes one pulse. Shape and amplify the pulses. Not given: the number of holes. Ours: an LED and a photodiode.
Izinto zokwakha zalesi sinyathelo:
Okokwakha okungaziwa1 slotted disk
Inhlanganisela yama-LED1 light source
I-Photodiode (BPW34)1 photodetector
Ukumelana nogesi1 isethiAmathuluzi adingekayo:
Ibhola lesandla3
3
Build the counting circuit
Build the counting circuit
Divide a quartz oscillator's clock down to gate pulses one unit of time long. Pass the measurement pulses through an AND gate during each gate pulse into a counter. At the start of each gate pulse a reset pulse clears the counter. After the gate pulse ends, the first measurement pulse that arrives triggers a latch pulse that loads the new count into the display. If the head has been taken off the shaft, no pulse arrives, no latch pulse is made, and the display keeps the last reading until the next measurement or until the power is switched off. Not given: the clock frequency and gate time. Ours: logic ICs and a seven-segment display.
Izinto zokwakha zalesi sinyathelo:
Ipuleti le-PCB1 ucezu
Ikristalu ye-quartz1 ucezu
Inhlanganisela yama-IC e-logic1 divider, AND gate, counter, latch, reset
Umshayeli Wesibonisi Esinezingxenye Eziyisikhombisa1 ucezu
Isibonisi Samadijithi Amane Esinezingxenye Eziyisikhombisa1 ucezu
Ucingo Lwesoda1 as neededAmathuluzi adingekayo:
Insimbi yokushisela4
4
Power it and measure
Power it and measure
Fit the battery and the thumb button as the power switch. Press the contact head against the end of the turning shaft so it turns with it, push the button, and read the revolutions in the window, now or after you take the tachometer away.
Izinto zokwakha zalesi sinyathelo:
Ibhethri1 ucezu
Inkinobho yokucindezela1 ucezuAmathuluzi adingekayo:
Insimbi yokushiselaIzinto
15- 1 housingIsibambeli
- 1 measuring shaftIsibambeli
- Isibambeli
- 1 slotted diskIsibambeli
- 1 light sourceIsibambeli
- 1 photodetectorIsibambeli
- 1 isethiIsibambeli
- 1 ucezuIsibambeli
- 1 ucezuIsibambeli
- 1 divider, AND gate, counter, latch, resetIsibambeli
- Isibambeli
- Isibambeli
- 1 as neededIsibambeli
- 1 ucezuIsibambeli
- Isibambeli
Amathuluzi Adingekayo
4- Isibambeli
- Isibambeli
- Isibambeli
- 2 vendors sell this, none ship to you yetIsibambeli
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