[DIY Bubble Etch Tank]

Hi all!

Today I built myself a simple bubble etch tank out of an aquarium pump, a plastic container and some tubing. I wrote up a tutorial on building the tank in case anyone is interested. You can download it in PDF format here.

I would like to perhaps publish this on other electronics websites. Any suggestions?

--Amr

[Helm PCB - PCB Manufacture for HOBBYISTS]

Hi all!

Helm PCB provides a PCB manufacturing service geared towards hobbysists. Unlike many large PCB houses, we do not impose a minimum size restriction on your PCBs or a minimum number of PCBs to order. You'll find our prices very competitive.

Visit us at www.helmpcb.com

[Led display Digital Voltmeter question]

Good news! I've just rebuilt the circuit using the Texas Instruments chip and breadboard and it works perfect! What's more, I replaced the TI chip for the Intersil one and it works just as well! I must have made some mistake in my PCB the first time. Anyway, I'm glad that's all sussed.

Thanks for all the comments and help everyone!

--Amr

[Led display Digital Voltmeter question]

I'm using the ICL7107CPL from Intersil. Incidently, I bought a Texas Instruments version today and plugged it in and the same thing happened. I think what will be best is if I scrap my old circuit and build another one from scratch. I find that sometimes helps to get kinks out that I miss. I'm still willing to hear any advice on the subject!

--Amr

[Led display Digital Voltmeter question]

I haven't used any kits. I came across the chip in a book and used the datasheet to design my circuit. When the circuit refused to work properly, I searched on the net for a solution and found this site.

I will try the bypass caps and see how it goes.

Thanks form the help so far!

--Amr

[Led display Digital Voltmeter question]

The circuit is powered by a regulated and smoothed dc power supply. Is this not good enough?

--Amr

[Led display Digital Voltmeter question]

I have the same problem as bassemessan. The meter readings are extremely unstable. The datasheet does specify that the oscillator capacitor should be ceramic, the integrator should be polypropylene and the reference and auto-zero should be Mylar or polystyrene. I have done so in my circuit and it's still just as unstable as ever. The meter is configured for 2V fullscale. I have fixed a 1M-100k potential divider so that I can input a maximum of 20V. I've attached my circuit diagram and PCb layout. Any help is greatly appreciated.

--Amr