Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

failure with project!

Status
Not open for further replies.
Sure, buy a Smartkit, I think from Greece. They are sold here too.
 
Answers to questions:
1) An opamp has an internal gain of about 300,000. A piece of wire about 1" long will pickup mains hum and all kinds of other interference and if it is at pin 2 of the opamp it is amplified about 300,000 times.
Therefore breadboards cause problems with circuits having high gain and a pcb should be used instead.

2) I don't know why you are using Eagle software for this simple project. The article has its schematic and a Veroboard or RadioShack board layout.
I don't use Eagle, I use Microsoft Paint to make schematics.

3) The multimeter by Smartkit is very old. Your pic shows an IC that was made in 1990. The Smartkit is a project at www.electronics-lab.com and causes people many problems as discussed in the forum. It wastes a lot of power lighting LEDs, most multimeters today use a low current LCD display.
 
audioguru said:
The multimeter by Smartkit is very old. Your pic shows an IC that was made in 1990. The Smartkit is a project at www.electronics-lab.com and causes people many problems as discussed in the forum. It wastes a lot of power lighting LEDs, most multimeters today use a low current LCD display.

ok, you're right! but what about ADC, can i connect LCD display directly as it is voltage value so analog (not digital)..what would you advise me to use for that purpose( showing the result digitally) so that in not expensive way and practical also...

I want to ask you curious question, how can you do schemaics without using software like eagle or similiar to it...this is difficult for me... please help me on doing schematic , if you don't mind and you haven't got bored of me :?

best regards!
 
The fairly old ICL7106 is designed to be an ADC voltmeter operating from a little 9V battery and driving a LCD display. You can make one if you can get the parts.
In Europe and North America, LCD voltmeter modules are common and much cheaper to buy assembled than it would cost for us to make one.
 
This is the schematic of my project (figure7)....but I don't know how to add display (ICL7107) using eagle, and how to power display .. how to connect the output voltage of stage2(second opamp) to the display? :shock:

**broken link removed**

anyway , take a look at this attachment!

best regards!
 
I don't know about Eagle.
You already posted a power supply for the LED digital voltmeter. This voltmeter's current is so high that little 9V batteries won't last very long. The 9V battery in my LCD multimeter lasts for years.
The linear output of your project connects to a voltage divider which feeds the input of the voltmeter so it that it scales from 0V to 200mV.
 
sorry

sorry, here it is
 

Attachments

  • light_sensity_meter.jpg
    light_sensity_meter.jpg
    32.3 KB · Views: 725
audioguru said:
I don't know about Eagle.
You already posted a power supply for the LED digital voltmeter. This voltmeter's current is so high that little 9V batteries won't last very long. The 9V battery in my LCD multimeter lasts for years.
The linear output of your project connects to a voltage divider which feeds the input of the voltmeter so it that it scales from 0V to 200mV.

You mean that i have to add voltage divider to the linear output of my project, how can i do that , what are the resistor values to suit that purpose?!
 
4electros said:
You mean that i have to add voltage divider to the linear output of my project, how can i do that , what are the resistor values to suit that purpose?!
If you can't figure out how to make a simple voltage divider then you could use trial and error until it works.
 
I've asked about IC7107CPL in electronic markets but they told me that it's available as ADC converter only.and i have to add display and other components that i need by myself .I shocked to hear that cause I thought that this IC contains ADC and display and many features also...
anyway i don't know what to say more but i really need your suggestions my friends :)

thanks in advance!
 
Didn't you look at its datasheet? **broken link removed**

Of course the ICL7107 is just a controller IC for making a digital panel meter with a separate LED display. Also, it needs a dual supply.

If you want an assembled meter, then buy one. LED meters are rare nowadays, most use an LCD display for low current from a 9V battery. Maybe you can steal one from an old multimeter.
 

Attachments

  • icl7107.png
    icl7107.png
    36.7 KB · Views: 838
Just a question about ICL7107 , Do I have to add the capacitors and resistors (as in the image above) externally to the IC ...I want to add LCD display as an output of ICL7107 instead of seven segment LEDS in order not to consume high current so that 9v battery won't last very long..

any suggestion will be appreciated !

thanks in advance!
 
4electros said:
Just a question about ICL7107 , Do I have to add the capacitors and resistors (as in the image above) externally to the IC ...I want to add LCD display as an output of ICL7107 instead of seven segment LEDS in order not to consume high current so that 9v battery won't last very long..

any suggestion will be appreciated !

You can't just replace LED's with LCD, they are completely different things, and driven in totally different ways. IC's were available to drive LCD displays, but would probably be difficult to find these days? - far easier to buy an LCD meter module (as Audioguru suggested) these are freely available at moderate cost, and include the LCD and driver IC joined together - they do everything you want!.

Have a look at for examples from one manufacturer.
 
If you want to drive an LCD display, have a look at the ICL7106. That is designed to drive an LCD rather than LEDs.

JimB
 
4electros said:
Just a question about ICL7107 , Do I have to add the capacitors and resistors (as in the image above) externally to the IC?
Of course the parts must be used.

I want to add LCD display as an output of ICL7107 instead of seven segment LEDS in order not to consume high current so that 9v battery won't last very long.
Don't you have the datasheet?
Don't you think you should use the right IC?
 

Attachments

  • icl7106.png
    icl7106.png
    30.1 KB · Views: 275
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top