# DIY servo tester



## tstraub (Feb 26, 2012)

I found a need for a tool that could output servo protocol at any pulse with I choose so I could move a servo threw its range of motion and find the pulse with required for any position the servo is capable of. I came up with a circuit that uses a PIC16F688 micro a 16x2 LCD, 4 tact switches and a few other parts. It runs from 3xAA batteries. Firmware was written in Great Cow Graphical BASIC. It can run up to 2 servos at the same time. Frame rate is 20 ms and pulse width is .5 ms to 2.5 ms in 10 us increments Cost to build is about $10.

Here is a short video of the working prototype in action.






And a screenshot of the proposed production board. 









Home etch files and firmware are available on request. I will male a post in the vendors section when production PCBs are ready for sale. Technical questions, comments, and suggestions are all welcome in this thread. Any questions directly related to sales should wait for the post in the vendors area.

Tyler


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## Jack Is Back (Jun 21, 2011)

I would definitely be interested and can't wait for availability. I've been wanting a servo tester for a long time but have never found one that does exactly what you've designed here. I was going to try and prototype something by my electronics skills are very sketchy.


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## niblique71 (Dec 2, 2009)

Hi Tyler, did you ever make a run of these boards?? If so do you have any more available?? And as always do you sell them with the components as a DIY kit, or just the board and a flashed picaxe chip? I will be placing an order to tayda soon, so a parts list (if needed) would be great


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## tstraub (Feb 26, 2012)

Yes I did do a small run over at the Christmas site I a member of but I never updated this thread. I have a dozen or so PCBs left over. We are in the Technological Terror forum so shoot me a PM for the ordering info.


```
Tayda pars list

SKU#	DESCRIPTION	PRICE	QNT	SUBTOTAL
	
A-1748	LCD Display 16 x 2 Blue Character with Backlight	$5.90	1 		$5.90	
A-2507	15K OHM Trimpot Variable Resistor 6mm			$0.06	1 		$0.06
A-214	0.1uF 50V Multilayer Ceramic Capacitor			$0.06	1 		$0.06	
A-5129	Tact Switch 6*6mm 7mm Through Hole SPST-NO		$0.04	4		$0.16	
A-2123	1K OHM 1/4W 5% Carbon Film Resistor			$0.01	10		$0.10
A-2115	10K OHM 1/4W 5% Carbon Film Resistor			$0.01	10		$0.10	
A-004	14 pin DIP IC Socket Adaptor Solder Type		$0.05	1		$0.05
A-196	40 Pin 2.54 mm Single Row Female Pin Header		$0.24	1		$0.24	
A-197	40 Pin 2.54 mm Single Row Pin Header Strip		$0.15	1		$0.15	
A-289	PIC16F688 8 bit Microcontroller IC			$1.90	1		$1.90	
A-199	40 Pin 2.54 mm Angle Single Row Pin Header		$0.17	1		$0.17	
A-4528	100UF 6.3V 105C RADIAL ELECTROLYTIC CAPACITOR 6X6MM	$0.02	1		$0.02
TOTAL 											$8.91
```
You will also need a 3 AA battery holder with a switch. Tayda has battery holders but none with a switch. There is no power switch on the PCB so if you use a Tayda battery holder you will need to remove the batteries when not in use.

You can find lots more info and pictures of the PCB over at diychristmas.org direct link to the thread here


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## Factrat (Apr 27, 2014)

*purchase a board ready for parts, or the complete servo tester?*

Is it possible to purchase a board ready for parts, or the complete servo tester? Thank you!

Factrat


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## toozie21 (Aug 23, 2012)

With Tyler's blessing, I had a few PCBs fabbed and am selling them at cost over in the For Sale area.


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