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八兆天空 发表于 2017-2-8 16:39:05

转载----用指针式电压表制作超 · 极客时钟！《无线电》杂志公众号

本帖最后由八兆天空于 2017-2-8 16:41 编辑

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无线电杂志微信号 radiomagazine

看到标题，可能很多朋友已经按捺不住自己了！没错！就是这种非常硬核的极客风格，今天来学习一下如何使用指针式的电压表来作为指针，显示当前的时间和温度吧！

实际上，这个设计原理非常好懂：单片机使用PWM并通过电阻分压来得到0~2V的电压值，而这个电压则是表头的满偏电压，而将其分成60份后，就可以用来指示60分钟或60秒的示数了。时间采用实时时钟DC1307来保存，而温度则通过读写单线温度传感器DS18B20得到。整个设计的主控单片机使用Picaxe 14M2单片机。不过说实话，这个单片机使用什么都无所谓，只要能够有三路PWM输出（或软或硬）即可。

原理非常简单，可能最难的地方在于如何分出适当的电压值。将2V分成60份，每份电压值为0.033V，因此表盘的设计和电压的输出就全都要参照这个电压值来设计。每增加一个分度，PWM都要相应地增加0.033V的电压值，而这又要考虑到PWM的精度和外部的低通滤波电路。因此这个设计还需要一定的思考才行！

其他的诸如操作DC1307和DS18B20的程序我想大家已经非常熟悉了，此处不再赘述。如果想要借鉴源程序的话欢迎在公众号的对话中回复“电压表时钟”以取得源程序哦！

本文为无线电杂志微信公众平台原创文章。详细内容及高清大图请查阅《无线电》杂志。版权所有，欢迎个人转发至朋友圈。公众号、报刊等转载请给本公众号后台留言获得授权。
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八兆天空 发表于 2017-2-8 16:39:42

电压表时钟 · 源程序
2017-01-16 WTH 无线电杂志

电压表时钟的正文，请看一楼

;源程序由WTH编写，运行于PicAxe

14M2上，阅读程序可以让你了解思

路。
; Project Name: 3 Panel Meter Clock
; REV: FIN (everything works fine with

clock and temp)
;
; Start Date:Feb 12, 2012
;
; Program Rev History/Ideas:
; - to set clock push M or H button
; - push main button to display temp

F, C, and K
; - Routine to drive 3 meters to full

scale when main button AND (M OR

H)
; is pressed.This is to allow

adjustment of trimmers to full scale.
; Adjustment to zero scale should be

done first with power off.
;
; *******************************
; PICAXE PE Rev: MacAXEPad 1.3.2
;
#picaxe14m2
'define memory locations as symbols
symbol hour_meter = c.0 'LEG 7
symbol minute_meter = c.2 'LEG 5
symbol second_meter = b.2 ' LEG 11
symbol temp_switch = pinc.4 ' LEG3
symbol temp_sensor = b.5 'LEG8
symbol hour_set = pinc.3 'LEG3
symbol minute_set = pinc.1 'LEG6
symbol CthermoValue = b10
symbol FthermoValue = b11
symbol KthermoValue = w6 'b12 and

b13
symbol seconds = b0
symbol minutes = b1
symbol hours = b2
symbol day = b3
symbol date = b4
symbol month = b5
symbol year = b6
symbol blinky = b7
symbol Tens_Digi = b8 ;Used to get

the Tens Digit from the $HEX RTC

value
symbol Ones_Digi = b9 ;Used to get

the Ones Digit from the $HEX RTC

value
' w7 (b14 and b15) is used to control

the PCM to the meters
' Set the time on the DS1307 RTC
i2cslave %11010000, i2cslow, i2cbyte ;

set PICAXE as master and DS1307

slave address
pause 50
'Set all meters to full scale with 100%

duty cycle
pwmout hour_meter,99,400
pwmout minute_meter,99,400
pwmout second_meter,99,400
'\/ \/ \/ \/ Un_REM THESE LINES

(BELOW) IF SETTING UP A NEW RTC\/

\/ \/ \/
#rem
' Set the RTC chip time
;write time and date e.g. to 11:59:00

on Thurs 25/12/03
'; would be "writei2c 0,($00, $59, $11,

$03, $25, $12, $03, 010000)"
' readi2c 0, (b0,b1,b2,b3,b4,b5,b6,b7)

reads back the data
let seconds = $00 ; 00-59 Note all

BCD format
let minutes = $00 ; 00-59 Note all

BCD format
let hours = $01 ; 01-12 Note all BCD

format
let day = $03 ; program does not

use date, date, month, year
let date = $22
let month = $03
let year = $12
let blinky = 000000 ; 010000 would

Enable output at 1Hz blink rate.

000000 is no blink
writei2c 0,(seconds, minutes, hours,

day, date, month, year, blinky)
pause 50
#endrem
'/\ /\ /\ /\ Un_REM THESE LINES

(ABOVE) IF SETTING UP A NEW RTC/\

/\ /\ /\
; POWER ON SELF TEST.Send all three

meters to FULL Scale and back to 0
'NOTE:pwmduty hour_meter, w7

---->> w7 ranges from 0 to 400 to

move meter from 0VDC to 2VDC
for w7 = 400 to 0 step -1' pwmduty

needs a (W)ord var, not a (B)yte var
pwmduty hour_meter, w7 'adjust

PWM Duty from 100% to 0%
pwmduty minute_meter, w7
pwmduty second_meter, w7
next w7
main:
if temp_switch = 1 then
do ' while hour_set = 1 or minute_set

= 1 then 'if main buttom and H or M

set button pushed then
pwmduty hour_meter, 400 ' move all

meters to full scale to allow trimmer

adjust.Do 0 meter adjust1st with

power off.
pwmduty minute_meter, 400
pwmduty second_meter, 400
loop while hour_set = 1 or minute_set

= 1
end if ' temp_switch = 1
if temp_switch = 1 and hour_set = 0

and minute_set = 0 then
do 'while temp_switch is pressed
gosub DisplayTemp
loop while temp_switch = 1 and

hour_set = 0 and minute_set = 0
end if
'read the RTC and display the time
readi2c 0, (seconds, minutes, hours,

day, date, month, year, blinky)
pause 10
'\/ \/ \/ \/ \/ SECONDS SECONDS

SECONDS \/ \/ \/ \/ \/
;Convert the Seconds from the RTC to

Base10 and update the meter
if temp_switch = 0 and minute_set =

1 and hour_set = 1 then 'all pressed.

Seconds to $00
gosub Seconds_set
end if
Ones_digi = seconds & 0x0F ' zero

out the top four bits
Tens_Digi = seconds & 0xF0 ' zero

out the lower four bits
Tens_Digi = Tens_Digi / 2 ' each

divide by 2 shifts the
Tens_Digi = Tens_Digi / 2 ' bits LEFT.

Four shift get
Tens_Digi = Tens_Digi / 2 ' them all to

the lower four bits
Tens_Digi = Tens_Digi / 2
Tens_Digi = Tens_Digi * 10 'Now shift

the Base10 value to Tens place
seconds = Tens_Digi + Ones_Digi

'complete. Now $ss is ss (in Base10)
' Update the seconds meter with a

w9 value of 0 to 400
w7 =seconds * 677 / 100;

(400/59=6.77) scale 0-59 seconds to

0-400 for PWM
pwmduty second_meter, w7
'/\ /\ /\ /\ SECONDS END /\ /\ /\ /\

/\ /\ /\
'\/ \/ \/ \/ MINUTES MINUTES

MINUTES \/ \/ \/ \/ \/
if temp_switch = 0 and minute_set =

1 and hour_set = 0 then 'if

temp_switch and M is pressed then

add on minute
gosub Minutes_set
end if
;Convert the Minutes from the RTC to

Base10 and update the meter
Ones_digi = minutes & 0x0F ' zero

out the top four bits
Tens_digi = minutes & 0xF0 ' zero

out the lower four bits
Tens_Digi = Tens_Digi / 2 ' each

divide by 2 shifts the
Tens_Digi = Tens_Digi / 2 ' bits LEFT.

Four shift get
Tens_Digi = Tens_Digi / 2 ' them all to

the lower four bits
Tens_Digi = Tens_Digi / 2
Tens_Digi = Tens_Digi * 10 'Now shift

the Base10 value to Tens place
minutes = Tens_Digi + Ones_Digi

'complete. Now $mm is mm (in

Base10)
'Update the minutes meter with a w9

value of 0 to 400
If minute_set = 0 then 'dont update if

we are setting the minutes.Should

correct this in Minutes_set routine
w7 = minutes * 677 / 100 ;

(400/59=6.77) scale 0-59 minutes to

0-400 for PWM
pwmduty minute_meter, w7
end if
'/\ /\ /\ /\ /\ MINUTES END /\ /\ /\ /\

/\
'\/ \/ \/ \/ \/ HOURS HOURS HOURS

\/ \/ \/ \/
if temp_switch = 0 and minute_set =

0 and hour_set = 1 then 'if

temp_switch and M is pressed then

add on minute
gosub Hours_set
end if
;Convert the Hours from the RTC to

Base10 and update the meter
Ones_digi = hours & 0x0F ' zero out

the top four bits
Tens_digi = hours & 0xF0 ' zero out

the lower four bits
Tens_Digi = Tens_Digi / 2 ' each

divide by 2 shifts the
Tens_Digi = Tens_Digi / 2 ' bits LEFT.

Four shift get
Tens_Digi = Tens_Digi / 2 ' them all to

the lower four bits
Tens_Digi = Tens_Digi / 2
Tens_Digi = Tens_Digi * 10 'Now shift

the Base10 value to Tens place
hours = Tens_Digi + Ones_Digi

'complete. Now $hh is hh (in Base10)
if hours > 12 then
hours = hours - 12
end if
if hours = 0 then
hours = 12
end if
' Update the hours meter with a w9

value of 0 to 400
w7 = hours * 3636; (400/11 = 36.36)

scale 1 to 12 hours to 0-400 for PWM
w7 = w7 - 3636 'subtracty interceot

to start PCM at 0 to 1 o'clock.
w7 = w7 / 100 'scale 1 to 12 hours to

0-400 for PWM
pwmduty hour_meter, w7
'/\ /\ /\ /\ /\ HOURS END /\ /\ /\ /\

/\
goto main
DisplayTemp:
readtemp temp_sensor,

CthermoValue
w7 = CthermoValue * 677 / 100

'(400/59=6.77) scale C to 0-400 for

PWM
pwmduty minute_meter, w7 'C (raw)

in the minutes meter)
'Convert C to F
FthermoValue = 9 * CthermoValue / 5

+ 32
w7 = FthermoValue * 364; (400/11 =

36.36)scale 10 to 120Fto 0-400 for

PWM
w7 = w7 - 3636 'subtracty interceot

to start PCM at 0 to 10F
w7 = w7 / 100 'scale 0-400 for PWM
pwmduty hour_meter, w7 '(F (x10) on

the hours meter
'Convert C to K
KthermoValue = CthermoValue + 273
w7 = KthermoValue / 10
w7 = w7 * 677 / 100
pwmduty second_meter, w7 'Kelvin

*100 on the seconds meter
return 'DisplayTemp
Seconds_Set:
seconds = $00
writei2c 0,(seconds, minutes, hours,

day, date, month, year, blinky)
pause 50
w7 =seconds * 677 / 100;

(400/59=6.77) scale 0-59 seconds to

0-400 for PWM
pwmduty second_meter, w7
return 'Seconds_set
Minutes_Set:
readi2c 0, (seconds, minutes, hours,

day, date, month, year, blinky)
;Convert the Minutes from the RTC to

Base10 and update the meter
Ones_digi = minutes & 0x0F ' zero

out the top four bits
Tens_digi = minutes & 0xF0 ' zero

out the lower four bits
Tens_Digi = Tens_Digi / 2 ' each

divide by 2 shifts the
Tens_Digi = Tens_Digi / 2 ' bits LEFT.

Four shift get
Tens_Digi = Tens_Digi / 2 ' them all to

the lower four bits
Tens_Digi = Tens_Digi / 2
Tens_Digi = Tens_Digi * 10 'Now shift

the Base10 value to Tens place
minutes = Tens_Digi + Ones_Digi

'complete. Now $mm is mm (in

Base10)
minutes = minutes + 1
if minutes > 59 then
minutes = 0
end if
'convert base10 minutes to BCD here

then write new minute value to RTC
Ones_Digi = minutes // 10
Tens_Digi = minutes - Ones_Digi
Tens_Digi = Tens_Digi / 10
Tens_Digi = Tens_Digi * 2' shift the

lower right bits
Tens_Digi = Tens_Digi * 2' to the

upper left.
Tens_Digi = Tens_Digi * 2
Tens_Digi = Tens_Digi * 2
Tens_Digi = Tens_Digi OR Ones_Digi

'OR function on the two values to get

8 bit BDC
'Now Ten_digi = minutes in packed

BCD.Just using Tens_Digi as a temp

var
writei2c 0,(seconds, Tens_Digi, hours,

day, date, month, year, blinky)
pause 50
'Update the minutes meter with a w9

value of 0 to 400
w7 = minutes * 677 / 100 ;

(400/59=6.77) scale 0-59 minutes to

0-400 for PWM
pwmduty minute_meter, w7
pause 500
return ' Minutes_Set
Hours_Set: 'HOURS SET WORKS

PERFECT
readi2c 0, (seconds, minutes, hours,

day, date, month, year, blinky)
;Convert the Hours from the RTC to

Base10 and update the meter
Ones_digi = hours & 0x0F ' zero out

the top four bits
Tens_digi = hours & 0xF0 ' zero out

the lower four bits
Tens_Digi = Tens_Digi / 2 ' each

divide by 2 shifts the
Tens_Digi = Tens_Digi / 2 ' bits LEFT.

Four shift get
Tens_Digi = Tens_Digi / 2 ' them all to

the lower four bits
Tens_Digi = Tens_Digi / 2
Tens_Digi = Tens_Digi * 10 'Now shift

the Base10 value to Tens place
hours = Tens_Digi + Ones_Digi

'complete. Now $hh is hh (in Base10)
hours = hours + 1
if hours > 12 then
hours = hours - 12
end if
if hours = 0 then
hours = 12
end if
if hours > 9 then
if hours = 10 then
hours = $10
end if
if hours = 11 then
hours = $11
end if
if hours = 12 then
hours = $12
end if
end if
writei2c 0,(seconds, minutes, hours,

day, date, month, year, blinky)
pause 50
;Convert the Hours from the RTC to

Base10 and update the meter
Ones_digi = hours & 0x0F ' zero out

the top four bits
Tens_digi = hours & 0xF0 ' zero out

the lower four bits
Tens_Digi = Tens_Digi / 2 ' each

divide by 2 shifts the
Tens_Digi = Tens_Digi / 2 ' bits LEFT.

Four shift get
Tens_Digi = Tens_Digi / 2 ' them all to

the lower four bits
Tens_Digi = Tens_Digi / 2
Tens_Digi = Tens_Digi * 10 'Now shift

the Base10 value to Tens place
hours = Tens_Digi + Ones_Digi

'complete. Now $hh is hh (in Base10)
' Update the hours meter with a w9

value of 0 to 400
w7 = hours * 3636; (400/11 = 36.36)

scale 1 to 12 hours to 0-400 for PWM
w7 = w7 - 3636 'subtracty interceot

to start PCM at 0 to 1 o'clock.
w7 = w7 / 100 'scale 1 to 12 hours to

0-400 for PWM
pwmduty hour_meter, w7
pause 1000

return ' Hours_Set

眉间尺 发表于 2017-2-8 17:17:53

好思路.
用4个或者5个表头, 每个表头只要能显示0-9这几个数值, 就可以让指针万用表具备与4位或者5位数码管显示的万用表相同的分辨率了.

yxlin000 发表于 2017-2-15 21:51:20

作者大才小用能有这样的技术我就去做表头和家用定时器不过作者可能是都会了才做些与众不同的东西:lol

hlw2957 发表于 2017-2-19 22:49:37

52jsj 发表于 2017-3-16 17:41:43

这是就是炫一下，没有什么实际效用，首先就是读数不明显

老柳发表于 2017-3-22 13:33:51

眉间尺发表于 2017-2-8 17:17
好思路.
用4个或者5个表头, 每个表头只要能显示0-9这几个数值, 就可以让指针万用表具备与4位或者5位数码 ...

每个表盘100刻度，视觉可直读两位数。两个表盘四位数，最大是9999，比三位半还强。
不过看完第一表盘，记住读数，再看第二表盘的读数，合拢起来才是结果，会很不方便，怪怪的，拿来玩可以。

w6955 发表于 2017-3-22 14:33:51

没有数码管的时代，就是用这个办法显示数字电路的输出的，按数字电路的权值取电阻就可以显示一位数字信息。

眉间尺 发表于 2017-3-22 17:01:56

老柳发表于 2017-3-22 13:33
每个表盘100刻度，视觉可直读两位数。两个表盘四位数，最大是9999，比三位半还强。
不过看完第一表盘， ...

看数码管如果看了个位忘了十位或者百位也不行啊.:lol

DIYYER 发表于 2017-3-22 20:48:55

学习看看听很高级

爱你矿坛 发表于 2017-3-22 20:49:16

不错的作品！
单片机，不懂。想学，老了，太迟了。

壹法拉 发表于 2017-3-26 13:38:03

不知道源程序是用什么语言写的。

ZJHFY 发表于 2017-3-30 19:49:04

独特风格学习一下

snb 发表于 2017-4-5 07:45:36

换三个猫头表加黄色背光更赞

岑蓉络阳 发表于 2017-4-5 09:44:22

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转载----用指针式电压表制作超 · 极客时钟！《无线电》杂志 公众号

转载----用指针式电压表制作超 · 极客时钟！《无线电》杂志公众号